Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Bio Zoology Guide Pdf Chapter 10 Neural Control and Coordination Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

11th Bio Zoology Guide Neural Control and Coordination Text Book Back Questions and Answers

 

Part -I.

I. Choose The Best Options

Question 1.
Which structure in the ear converts pressure waves to action potentials?
a) Tympanic membrane
b) Organ of Corti
c) Oval window
d) Semicircular canal
Answer:
b) Organ of Corti

Question 2.
Which of the following pairings is correct
a) Sensory nerve – afferent
b) Motor nerve – afferent
c) Sensory nerve – ventral
d) Motor nerve – dorsal
Answer:
a) Sensory nerve – afferent

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 3.
During synaptic transmission of nerve impulse, neurotransmitter (P) is released from synaptic vesicles by the action of ions
(Q). Choose the correct P and Q.
a) P = Acetylcholine, Q = Ca++
b) P = Acetylcholine, Q = Na+
c) P = GABA, Q = Na+
d) P = Cholinesterase, Q = Ca++
Answer:
a) P = Acetylcholine, Q = Ca++

Question 4.
Examine the diagram of the two cell types A and B given below and select the correct option.
a) Cell – A is the rod cell found evenly all over retina
b) Cell – A is the cone cell more concentrated in the fovea centralis
c) Cell – B is concerned with colour vision in bright light
d) Cell – A is sensitive to bright light intensities
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 1
Answer:
c) Cell – B is concerned with colour vision in bright light

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 5.
Assertion- The imbalance in concentration of Na+, K+ and proteins generates action potential.
Reason: To maintain the unequal distribution of Na+ and K+ , the neurons use electrical energy.
a) Both Assertion and Reason are true and Reason is the correct explanation of the Assertion.
b) Both Assertion and Reason are true but the Reason is not the correct explanations of Assertion.
c) Assertion is true, but Reason is false.
d) Both Assertion and Reason are false.
Answer:
a) Both Assertion and Reason are true and Reason is the correct explanation of the Assertion.

Question 6.
Which part of the human brain is concerned with the regulation of body temperature?
a) Cerebellum
b) Cerebrum
c) Medulla oblongata
d) Hypothalamus
Answer:
d) Hypothalamus

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 7.
The respiratory centre is present in the
a) Medulla oblongata
b) Hypothalamus
c) Cerebellum
d) Thalamus
Answer:
a) Medulla oblongata

Question 8.
Match the following human spinal nerves in column I with their respective number in column II and choose the correct option
Column I Column 11
(P) Cervical nerves
(Q) Thoracic nerve
(R) Lumbar nerve
(S) Coccygeal nerve
(i) 5 pairs
(ii) 1 pair
(iii) 12 pairs
(iv) 8 pairs
a) (P-iv), (Q-iii), (R-i), (S-ii)
b) (P-iii), (Q-i), (R-ii), (S-iv)
c) (P-iv), (Q-i), (R-ii), (S-iii)
d) (P-ii), (Q-iv), (R-i), (S-iii)
Answer:
a) (P-iv), (Q-iii), (R-i), (S-ii)

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 9.
Which of the following cranial nerve controls the movement of eye ball?
a) Trochlear nerve
b) Optic nerve
c) Olfactory nerve
d) Vagus nerve
Answer:
a) Trochlear nerve

Question 10.
The abundant intracellular cation is
a) H+
b) K+
c) Na+
d) Ca++
Answer:
b) K+

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 11.
Which of the following statements is wrong regarding conduction of nerve impulse.
a) In a resting neuron, the axonal membrane is more permeable to K+ ions and nearly impermeable to Na+ ions.
b) Fluid outside the axon has a high concentration of Na+ ions and low concentration of K+, in a resting neuron.
c) Ionic gradient s are maintained by Na+ K+ pumps across the resting membrane, which transport 3 Na ions outwards for 2K+ into the cell.
d) A neuron is polarized only when the outer surface of the axonal membrane possess a negative charge and its inner surface is positively charged.
Answer:
b) Fluid outside the axon has a high concentration of Na+ ions and low concentration of K+, in a resting neuron.

Question 12.
All of the following are associated with the myeline sheath except
a) Faster conduction of nerve impulses
b) Nodes of Ranvier forming gaps along the axon
c) Increased energy output for nerve impulse conduction
d) Saltatory conduction of action potential
Answer:
c) Increased energy output for nerve impulse conduction

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 13.
Several statements are given here in reference to cone cells which of the following option indicates all correct statements for cone cells? Statements
(i) Cone cells are less sensitive in bright light than Rod cells
(ii) They are responsible for colour vision
(iii) Erythropsin is a photo pigment which is sensitive to red colour light
(iv) They are present in fovea of retina
a) (iii), (ii) and (i)
b) (ii), (iii) and (iv)
c) (i), (iii) and (iv)
d) (i), (ii) and (iv)
Answer:
c) (i), (iii) and (iv)

Question 14.
Which of the following statement concerning the somatic division of the peripheral neural system is incorrect?
a) Its pathways innervate skeletal muscles
b) Its pathways are usually voluntary
c) Some of its pathways are referred to as reflex arcs
d) Its pathways always involve four neurons
Answer:
d) Its pathways always involve four neurons

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 15.
When the potential across the axon membrane is more negative than the normal resting potential, the neuron is said to be in a state of
a) Depolarization
b)FIyperpo1ariation
c) Repolarization
d) Hypopolaiization
Answer:
c) Repolarization

Question 16.
Why is the blind spot called so?
Answer:
Slightly below the posterior pole of the eye, the optic nerve and the retinal blood vessels enter the eye. This region is devoid of rods and cones. Hence, this region is called blind spot.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 17.
Sam’s optometrist tells him that his intraocular pressure is high. What is this condition called and which fluid does it involve?
Answer:

  • The increase in intraocular pressure leads to the disease called Glaucoma.
  • Any block in the canal of Schlemm increases the intraocular pressure of aqueous humor and leads to ‘Glaucoma’ where the optic nerve and the retina are compressed due to pressure.

Question 18.
The action potential occurs in response to a threshold stimulus: but not at sub-threshold stimuli. what is the name of the principle involved?
Answer:
When we cry, the tears come out of the tear glands under the eyelids and drain through the tear duct that empties into the nose. It mixes with mucus there and the nose runs.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 19.
Pleasant smell of food urged Ravi to rush into the Kitchen. Name the parts of the brain involved in the identification of food and emotional responses to odour
Answer:
The hypothalamus contains a pair of small rounded body called mamillary bodies that are involved in olfactory reflexes and emotional responses to odour
This is also act as centre for appetite thirst and heat regulation.

Question 20.
Cornea transplant in humans is almost never rejected State the reason.
Answer:
The cornea does not have blood vessels. Hence there is no possibility of rejection when the cornea is transplanted from one person to another person.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 21.
At the end of repolarisation, the nerve membrane gets hyperpolarized Why?
Answer:
If repolarization becomes more negative than the resting potential – 70mV to about – 90mV it is called hyperpolarization.

Question 22.
Label the parts of the neuron.
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 2
A- Nucleus with nucleolus
B- Axolemma
C- Dendrites
D- Myelin sheath, Nucleus
E- Axon (Direction of signal transmission)
F- Node of Ranvier.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 23.
The choroid plexus secretes cerebral spinal fluid List the function it.
Answer:
Cerebrospinal fluid provides buoyancy to the central nervous system.

  1. It acts as a shock absorber for the brain and spinal cord.
  2. It nourishes the brain cells by transporting food and oxygen.
  3. It carries harmful metabolic wastes from the brain to the blood.
  4. It maintains constant pressure inside the cranial vessels.

Question 24.
What is the ANS controlling center? Name the parts that are supplied by the ANS?
Answer:
Controlling center – autonomic neural system. Controlling organs.

  1. Eyes
  2. Salivary Glands
  3. Heart
  4. Lungs
  5. Stomach
  6. Liver
  7. Kidney
  8. Intestines
  9. Bladder

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 25.
Why the limbic system is called the emotional brain. Name the parts of it?
Answer:
The limbic system is a set of components located on both sides of the thalamus present in the inner part of the cerebral hemisphere. It includes the olfactory bulbs, cingulate gyrus, mammillary body, amygdala, hippocampus and hypothalamus. The limbic system plays a primary role in the regulation of pleasure, pain, anger, fear, sexual feeling, affection and memory. Hence it is called the emotional brain.

Question 26.
Classify receptors based on the type of stimuli.
Answer:

Receptors Stimulus Effector organs
Mechano receptors Pressure and vibration Mechano receptors are present in the cochlea of the inner ear and the semicircular canal and utriculus
Chemoreceptors Chemicals Taste buds in the tongue and nasal epithelium
Thermo receptors Temperature Skin
Photoreceptors Light Rod and cone cells of the retina in the eye.

Question 27.
Name the first five cranial nerves, their nature and their functions
Answer:

Cranial nerves Nature of nerve Function
I. Olfactory nerve Sensory Sense of smell
II.Optic nerves Sensory Sense of sight
III. Oculo motor nerves Motor Movement of the eye
IV. Trochlear nerve Motor Rotation of the eyeball
V.Trigeminal nerve Sensory and motor mixed The functioning of face ball

Question 28.
The sense of taste is considered to be the most pleasurable of all senses. Describe the structure of the receptor involved with a diagram.
Answer:

  • The sense of taste is considered to be the most pleasurable of all senses.
  • The tongue is provided with many small projections called papillae.
  • Taste buds are located mainly on the papillae.
  • Taste buds are flask-shaped.

There are two major types.

  • Gustatory epithelial cells or taste cells.
  • Basal epithelial cells or repairing cells.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 3

  • Long microvilli called gustatory hairs project from the tip of the gustatory cells and extend through a taste pore to the surface of the epithelium.
  • Gustatory hairs are the sensitive portion of the gustatory cells and they have sensory dendrites which send the signal to the brain.
  • The basal cells that act as stem cells divide and differentiate into new gustatory cells.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 29.
Describe the structures of olfactory receptors?
Answer:
The smell receptors are excited by air-borne chemicals that dissolve in fluids. The yellow coloured patches of olfactory epithelium form the olfactory organs that are located on the roof of the nasal cavity.

The olfactory epithelium is covered by a thin coat of mucus layer below and olfactory glands bounded connective tissues, above. It contains three types of cells: supporting cells, Basal cells and millions of pin-shaped olfactory receptor cells (which are unusual bipolar cells).

The olfactory glands and the supporting cells secrete the mucus. The unmyelinated axons of the olfactory receptor cells are gathered to form the filaments of olfactory nerve [cranial nerve-I] which synapse with cells of olfactory bulb.

The impulse, through the olfactory nerves, is transmitted to the frontal lobe of the brain for identification of smell and the limbic system for the emotional responses to odour.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 4

Part-II.

11th Bio Zoology Guide Neural Control and Coordination Additional Important Questions and Answers

I. Choose The Correct Answer

Question 1.
What is the functional unit of the nervous system?
a) Neuroglial cells
b) Neuron
c) Nephron
d) Axon
Answer:
b) Neuron

Question 2.
Name the nutritive cells of neuron.
a) Axon
b) Neuroglia
c) Schwann’s cell
d) Epithelial cells.
Answer:
b) Neuroglia

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 3.
Name the cell organelle which is not seen in the nerve cell.
a) Mitochondria
b) Golgi apparatus
c) Centrioles
d) Nucleus
Answer:
c) Centrioles

Question 4.
Name the plasma membrane which surrounds the neurons?
a) Neurilemma
b) Axolemma
c) Myalin membrane
d) Sarcolemma
Answer:
a) Neurilemma

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 5.
Name the plasma membrane surrounds the axon?
a) Neurilemma
b) Myalin membrane
c) Sarcolemma
d) Axolemma
Answer:
d) Axolemma

Question 6.
Where is Nissl’s bodies seen in the nerve cell?
a) Cell body and dendrites
b) Cell body and axon
c) Cell body and myalin sheath
d) Cell body and end plate of axon.
Answer:
a) Cell body and dendrites

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 7.
Name the cell organell which is not seen in the axons.
a) Mitochondria
b) Golgi apparatus
c) Centriole
d) Endoplasmic reticulum
Answer:
b) Golgi apparatus

Question 8.
Cell forms the myalin sheath ……………..
a) Schwaan’s cell
b) Neuroglial cells
c) Nephron
d) Epithelial cells
Answer:
a) Schwaan’s cell

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 9.
Which part of the nerve cells do not contain myalin sheath.
a) Axon
b) Cell body
c) Dentrites
d) Axon end plate
Answer:
c) Dentrites

Question 10.
Which of the following does the work of phagocytosis of microbes during the infection of the brain
a) Schwann cells
b) Node of Ranvier
c) Neuroglial cells
d) Neurilemma
Answer:
c) Neuroglial cells

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 11.
Find out the correct statement
a) The short nerve fibres are called as dentrites.
b) The membrane surrounds the neuron is axolemma.
c) The longest sciatic nerve runs from the base of the spine to the big toe of each foot
d) Schwann cell’s do not synthesize myalin sheath
Answer:
c) The longest sciatic nerve runs from the base of the spine to the big toe of each foot

Question 12.
Find out the wrong pair
a) Multi polar neuron: One axon and two or more dentrites.
b) Bi polar neurons: One axon and more than two dentrites.
c) Uni polar neurons: Short process axon.
d) Synaptic Knob: Neurotransmitters
Answer:
b) Bi polar neurons: One axon and more than two dentrites.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 13.
This substance is more in the tissue fluid of cytoplasm of axolemma?
a) Sodium chloride and bicarbonates.
b) Nutritious substances and oxygen.
c) Potassium and magnesium phosphate.
d) All the above.
Answer:
c) Potassium and magnesium phosphate.

Question 14.
Match the following and find the answer.

1. Leakage channels a. Opens through the sensation of touch and pressure.
2. Ligand-gated channels b. They are stable.
3. Voltage gated channels c. Opens through chemical stimulation.
4. Charged particles d. Ionic channels are always open.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 5
Answer:
c) i- B,ii – D,iii – C,iv – A

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 15.
Name the gaps in the myelin sheath between adjacent Schwann.
a) Nodes of Ranvier
b) Nodes of axon
c) Nodes of cyton
d) Nodes of dentrites
Answer:
a) Nodes of Ranvier

Question 16.
Where are bipolar neurons situated?
a) Cranial nerves
b) Olfactory lobes of brain
c) Spinal nerves
d) Skin
Answer:
b) Olfactory lobes of brain

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 17.
Where are Bipolar neurons situated?
a) Spinal cord
b) Retina
c) Inner ear
d) Brain.
Answer:
a) Spinal cord

Question 18.
Find out the odd one.
a) Schwann cell – Myalin sheath
b) Synaptic knob – Synaptic vesicles
c) Bipolar neuron – Cranial nerves
d) Multipolar neuron – Spinal nerves.
Answer:
c) Bipolar neuron – Cranial nerves

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 19.
Where is Bipolar neurons meet?
a) Synapses
b) Synaptic cleft
c) Synaptic vesicle
d) Synaptic Knob
Answer:
a) Synapses

Question 20.
Match and find the correct sequence.

I. Neuro junction a. Neuron which receives a stimulus
II. Presynaptic neurons b. Synaptic vesicles
III. Synaptic cleft c. Synapses
IV. Neurotransmitter d. Pre and post neuron junction

a) I-d II-a ¡II-c IV-d
b) I-a II-c III-d IV-b
c) I-a II-b III-c IV-d
d) I-c II-a III-d IV-b
Answer:
d) I-c II-a III-d IV-b

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 21.
Central nervous system forms from this layer during embryonic development.
a) Endoderm
b) Ectoderm
c) Mesoderm
d) Middle layer.
Answer:
b) Ectoderm

Question 22.
Find out whether the following statements are true or false. Find out the correct sequence.
i. The thick outer covering of the brain is dura matter
ii. The space between pia matter and dura matter is subarachnoid space.
iii. The membrane that surrounds the brain is piamalter
iv. The space between arachnoid and pia mater is subarachnoid space
a) I – False; II – False; III – True; IV – True
b) I-True; II-False; III-True; IV-True
c) I – True; II – False; III – False; IV – True
d) I-True; II-False; III-True; IV-False
Answer:
b) I-True; II-False; III-True; IV-True

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 23.
Which is considered as the seat of intelligence.
a) Cerebellum
b) Cerebrum
c) Medulla oblongata
d) Pons.
Answer:
b) Cerebrum

Question 24.
Find out whether the following statements are true or false.
a) At resting membrane potential the efflux of potassium is more than the influx of sodium from the outer surface of the neurilemma.
b) When the stimulus is sent from the cell body to the axon there is no creation of action potential.
c) The spike potential is +45mV.
d) The threshold potential is +55mV.
i) a) True b) True c) False d) False
ii) a) False b) True c) True d) True
iii) a) True b) False c) True d) True
iv) a) True b) False c) True d) False
Answer:
iv) a) True b) False c) True d) False

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 25.
Find out the wrong pair
a) Synapses – The junction of two neurons
b) Neurotransmitter – Postsynaptic neuron
c) Synaptic vesicles – A small bag filled with chemicals
d) Piamatter – Membrane which closely adheres to the brain.
Answer:
b) Neurotransmitter – Postsynaptic neuron

Question 26.
………………. is the part of the fore-brain.
a) Cerebrum – Mesencephalon
b) Cerebrum – Prosencephalon
c) Cerebrum – Diencephalon
d) Cerebrum – Parietal lobe.
Answer:
c) Cerebrum – Diencephalon

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 27.
…………………….. is useful in diagnosis of neurological and sleep disorders.
a) PET
b) CT
c) X – rays
d) EEG
Answer:
d) EEG

Question 28.
Name the structure which connects cerebral hemisphere
a) Choroid tissue
b) Corpus callosum
c) Neuroglia tissue
d) Pineal body
Answer:
b) Corpus callosum

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 29.
Match and find out the correct sequence.

I. Frontal lobe a. Reading
II. Parietal lobe b. Hearing
III. Temporal lobe c. Vision
IV. Occipital lobe d. Memory

a) I-d II-a III-c IV-b
b) I-a II-c III-d IV-b
c) I-a II-b III-c IV-d
d) I-d II-a III-b IV-c
Answer:
d) I-d II-a III-b IV-c

Question 30.
Assertion: Statement A- The cortex of cerebrum consists of grey matter.
Statement B- The reason for the grey matter is due to the presence of non – myelinated sheath.
a) Statement A- True, Statement B – False
b) Statement A and B are true
c) Statement A- False the statement B- True.
d) Statement A and B are false.
Answer:
b) Statement A and B are true

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 31.
Match and find the correct answer.
1. Broca area a. Perception of taste.
2. The pre-central gyrus b. Voluntary movements
3. The postcentral gyrus c. Aggression
4. Amygdala d. Speech function
a) I-a II-b III-c IV-d
b) I-d II-b III-c IV-a
c) I-d II-b Ill-a IV-c
d) I-a II-b III-c IV-d
Answer:
c) I-d II-b III-a IV-c

Question 32.
Assertion: Statement S – Brain controls emotions and feelings.
Statement T – There are no sensory neurons in the brain. Hence it cannot sense the pain.
a) Statement – S – True. Statement T – False
b) Statement – S – True Statement T – True
c) Statement – S – False Statement T – False
d) Statement S – False Statement T – True
Answer:
b) Statement – S – True Statement T – True

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 33.
Which is considered as the relay centre for impulses
a) Medulla oblongata
b) Cerebrum
c) Hypothalamus
d) Thalamus
Answer:
d) Thalamus

Question 34.
Which indicates A, B, C and D in the following diagram
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 6
(a)
a) Temporal lobe
b) Frontal lobe
c) Parietal lobe
d) Cerebellum
(b)
a) Cerebellum
b) Parietal lobe
c) Temporal lobe
d) Frontal lobe
(c)
a) Cerebellum
b) Frontal lobe
c) Temporal lobe
d) Parietal lobe
(d)
a) Parietal lobe
b) Cerebellum
c) Frontal lobe
d) Temporal lobe
Answer:
(b)
a) Cerebellum
b) Parietal lobe
c) Temporal lobe
d) Frontal lobe

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 35.
Find out the wrong statement.
a) The pre-central gyrus is called a motor strip.
b) The post-central gyrus is called a sensory strip.
c) The medulla oblongata controls respiration.
d) Wernicke area of the brain involved in the comprehension of speech.
Answer:
d) Wernicke area of the brain involved in the comprehension of speech.

Question 36.
The melatonin hormone which controls the sleep-wake cycle is secreted by
a) Pineal body
b) Thalamus
c) Hypothalamus
d) Medulla oblongata
Answer:
a) Pineal body

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 37.
The lower portion of the midbrain consists of a pair of longitudinal nervous bands called
a) Emotional brain
b) Cerebral peduncles
c) Pons
d) Vermis
Answer:
b) Cerebral peduncles

Question 38.
The cauda equina presents in
a) Cerebrum
b) Thalamus
c) Hippo cambus
d) Spinal cord
Answer:
d) Spinal cord

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 39.
Match and find the correct answer.
i) Thalamus – A) Respiration Gastric Pits.
ii) Hypothalamus – B) Vision Hearing
iii) Mid brain – C) Satiety centre
iv) Medulla oblongata – D) Learning memory
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 7
Answer:
a) i- D,ii – C,iii – B,iv – A

Question 40.
The cluster of nerve tissue in the cell body of neurons are called as
a) Gyri
b) Sulci
c) Vermis
d) Nerve ganglion.
Answer:
d) Nerve ganglion.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 41.
Find out the wrong pair
a) Cervical nerve – 8 pairs
b) Thoracic nerve – 12 pairs
c) Sacrum nerve – 4 pairs
d) Coccyx nerve – 1 pair
Answer:
c) Sacrum nerve – 4 pairs

Question 42.
What is the amount of cerebrospinal fluid secreted in an adult?
a) 500 ml
b) 150 ml
c) 400 ml
d) 250 ml
Answer:
b) 150 ml

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 43.
The dissolved nicotene and alcohol in …………………… and ………………… minutes reach the brain.
a) 7 and 8 minutes
b) 6 and 7 minutes
c) 7 seconds and 6 minutes
d) 7 and 5 minutes.
Answer:
c) 7 seconds and 6 minutes

Question 44.
Name the structure that regulates homeostasis.
a) Mammillary body
b) Pineal body
c) Hypothalamus
d) Pituitary.
Answer:
a) Mammillary body

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 45.
What is brain stem.
a) The structure seen in between spinal cord and cerebellum.
b) The region between Diencephalon and spinal cord
c) The region between medulla oblongata and cerebrum.
d) The region between medulla oblongata and mid-brain.
Answer:
b) The region between Diencephalon and spinal cord

Question 46.
What is the function of corpora quadri gemina?
a) Vision and hearing
b) Vision and homeostasis
c) Hearing and sense of touch
d) Hearing and vomiting.
Answer:
a) Vision and hearing

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 47.
The region seen in the mid of cerebellum.
a) Corpus callosum
b) Pineal body
c) Pituitary
d) Vermis.
Answer:
d) Vermis.

Question 48.
What is the function of the interneuron?
a) Impulses from afferent and efferent neurons.
b) Impulses transmitted from efferent neurons to afferent neurons.
c) Impulses transmitted from central nervous system to receptor organs
d) From nerve transmitters to the spinal cord
Answer:
a) Impulses from afferent and efferent neurons.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 49.
Which part of the brain controls the unconditioned reflux?
a) The cortex of cerebrum
b) The medulla of brain
c) Cerebellum
d) pons.
Answer:
a) The cortex of cerebrum

Question 50.
……………………..pair of nerves from cranium and
…………………….. pair of nerves from spinal cord
a) 10 and 31
b) 12 and 31
c) 31 and 12
d) 31 and 10.
Answer:
b) 12 and 31

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 51.
How much cerebrospinal fluid is synthesized in adults?
a) 200ml
b) 300ml
c) 150ml
d) 100ml.
Answer:
c) 150ml

Question 52.
What is the function of vagus nerve?
a) It regulates the function of abdominal structure
b) It regulates the speech and swallowing
c) It regulates the homeostasis of the body
d) Taste perception
Answer:
a) It regulates the function of abdominal structure

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 53.
Name the neural system which is auto functioning and self-governed.
a) Somatic neural system
b) Automatic neural system
c) Peripheral neural system
d) Limbic system.
Answer:
b) Automatic neural system

Question 54.
Name the structure that regulates the autonomic neural system.
a) Cerebrum
b) Cerebellum
c) Hypothalamus
d) Pons.
Answer:
c) Hypothalamus

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 55.
Name the lubricating fluid which is secreted from the gland present at the base of the eyelashes.
a) Lacrymal gland
b) Cerebro-spinal fluid
c) Thymus gland
d) Sebaceous glands.
Answer:
d) Sebaceous glands.

Question 56.
Find the ABC and D in the diagram
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 8
a) a) Tear duct b) Sciera c) Iris d) Tear gland
b) a) Sciera b) Iris c) Tear gland d)Tear duct
c) a) Tear duct b) Iris c) Sclerad d)lTear duct
d) a) Tear gland b) Sclera c) Tear duct d) Iris.
Answer:
d) a) Tear gland b) Sclera c) Tear duct d) Iris.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 57.
Name the tissue which forms the non-vascular transparent coat cornea
a) Stratified squamous epithelium
b) Squamous epithelium
c) Canal of schlemm
d) All the above.
Answer:
a) Stratified squamous epithelium

Question 58.
Assertion: In bright light the circular muscle in the iris contract so that the size of the pupil decreases and the light enter is regulated Reason: In dim light, the radial muscle contract the pupil size increases and less light enters the eye.
a) The assertion true: but reason wrong
b) The assertion and reason are true
c) The assertion is true but reason does not explain the assertion
d) The assertion and reason are wrong.
Answer:
a) The assertion true: but reason wrong

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 59.
Name the yellow flat spot at the centre of the posterior region of the retina.
a) Blind spot
b) Scelera
c) Iris
d) Maculalutea
Answer:
d) Maculalutea

Question 60.
Which colour is perceived through chloropsin is sensitive to the medium wavelength of 530 mm
a) Red cones
b) Green cones
c) Blue cones
d) Red cells.
Answer:
b) Green cones

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 61.
Name the glands that secrete tear.
a) Lacrymal gland
b) Sebaceous gland
c) Mandibular gland
d) Choroid plexues
Answer:
a) Lacrymal gland

Question 62.
…………………… enzyme is present in the tear.
a) Ptyalin
b) Lysozyme
c) Lipase
d) Erypsin.
Answer:
b) Lysozyme

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 63.
Name the structure where more cones present.
a) Foveacenlralis
b) Maculalutea
c) Retina
d) Blind spot.
Answer:
a) Foveacenlralis

Question 64.
……………………………….. people can see the nearby object but cannot see the distant object.
a) Astigmatism
b) Presbiopia
c) Hypermetropia
d) Myopia
Answer:
d) Myopia

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 65.
The concave lens helps in correct ………………. defect
a) Myopia
b) Hyper metropia
c) Astigmatism
d) Presbiopia
Answer:
a) Myopia

Question 66.
Which of the defect is depicted in the following diagram:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 9
a) Emmetropia
b) Myopia
c) Hypermetropia
d) Astigmatism.
Answer:
b) Myopia

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 67.
Match and find the correct sequence.

I. Concave Surgery
II. Convex Hypermetropia
III. Cataract Astigmatism
IV. Cylindrical lens Myopia

a) 1 -a 2-b 3-c 4-c
b) 1 -d 2-b 3-a 4-c
c) 1-d 2-a 3-a 4-b
d) 1-d 2-c 3-b 4-c
Answer:
b) 1 -d 2-b 3-a 4-c

Question 68.
Name the organ which regulates vision perception and homeostasis.
a) Ear
b) Eye
c) Cerebrum
d) Cerebellum.
Answer:
a) Ear

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 69.
Find out the wrong pair.
a) Pinna – Eardrum
b) Oval window – Round window
c) Cochlea – Malleus
d) Perilymph – Endolymph
Answer:
c) Cochlea – Malleus

Question 70.
Indicate ABC and D in the Diagram.
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 10
a)
a) lncus
b) Eardrum
c) Organ of Corti
d) Tactoreal membrane.
b)
a) Organ of cortri
b) Incus
c) Tectoreal membrane
d)Eardrum
c)
a) Eardrum
b) Incus
c) Organ of Corti
d) Tectoreal membrane
d)
a) Eardrum
b) Incus
c) Tectoreal membrane
d) Organ of Corti
Answer:
d)
a) Eardrum
b) Incus
c) Tectoreal membrane
d) Organ of Corti

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 71.
Find out the wrong statement.
a) The equilibrium receptor regions called maculae are involved in detecting the linear movement of the head.
b) The otoliths are made up of calcium
c) The crista ampullaris is to detect rotational movement of the head
d) Severe hearing loss occurs with frequent exposure to sound with intensities greater than50db.
(The 90db will affect the hearing).
Answer:
d) Severe hearing loss occurs with frequent exposure to sound with intensities greater than50db.

Question 72.
A person on his way to a village in a car for weekend holidays after finishing the office work. As he is very tired he begins to feel drowsy. He turns up the car stereo volume opens the car window and has sips ice-cold water.
How do these actions keep him awake? The increase in the number of sensory stimuli he received is relayed to the cerebral cortex which gets activated and prevents sleeping,
a) Spinal cord
b) Cerebrum
c) Medulla oblongata
d) Cerebellum.
Answer:
c) Medulla oblongata

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 73.
Name the structure that connects the middle ear and pharynx.
a) Eustachian tube
b) Middle ear
c) Oval window
d) Organ of the cortii.
Answer:
a) Eustachian tube

Question 74.
Which part of the ear have bony labyrinth and membranous labyrinth?
a) External ear
b) Inner ear
c) Middle ear
d) None of the above.
Answer:
b) Inner ear

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 75.
Name the structure present in the bony labyrinth.
a) Cochlea, vestibule, maleus
b) Cochlea, vestibule Incus
c) Cochlea semicircular canals, stapes
d) Cochlea, vestibule semicircular canals.
Answer:
d) Cochlea, vestibule semicircular canals.

Question 76.
Where is the stereo cilia cells present in the ear?
a) Scala media
b) Scala vestibuli
c) Scala tymnani
d) Middle ear.
Answer:
a) Scala media

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 77.
Match and find the correct sequence.

I. Meissner’s corpuscles a) continuous pressure
II. Pacinian corpuscles b) hardness, pain
III. Ruffini endings c) temperature
IV. Krause and bulbs d) light pressure

a) I-d, II-a, III-c, IV-d
b) I-d, II-b, III-c, V-a
c) I-d, II-b, Ill-a, IV-c
d) I-a, II-b, III-c, IV-d
Answer:
c) I-d, II-b, Ill-a, IV-c

Question 78.
When a cockroach tries to enter into the ear of a sleeping person, which one of the following process will start?
a) Unconditioned reflex
b) Neuro muscular fatigue
c) Stimulation of negative feedback mechanism
d) conditioned reflex
Answer:
a) Unconditioned reflex

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 79.
What is the number of nerve cells present in the brain
a) 90 million
b) 100 billion
c) 90 billion
d) 100 million
Answer:
b) 100 billion

(2 Marks)

II. Write Very Short Answer

Question 1.
What are the two branches of human nervous system?
Answer:

  1. Central nervous system
  2. Peripheral nervous system

Question 2.
What is meant by Neuroglia? What are its functions?
Answer:
The non-nervous special cells called neuroglia from the supporting cells of the nervous tissue.

  1. Providing nourishment to the neurons
  2. Repairing the injured tissues
  3. It helps in dividing and regeneration
  4. Acting as phagocyte cells to engulf the foreign particles at the time of any injury to the brain.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 3.
Differentiate the functions of myelinated and non-myelinated neurons.
Answer:

Myelinated neuron Non-myelinated neuron
They conduct impulses rapidly Conduct impulse slowly
Present in the medulla Seen in the cortex of the cerebrum.

Question 4.
Give notes on (a) Synaptic Knob (b) Neurotransmitters (c) Inter neural space.
Answer:

  • Synaptic Knob: Distant end of the axon terminates into a bulb
  • Synaptic vesicles: Vesicles filled with neurotransmitters
  • Inter neural space – The space between presynaptic and postsynaptic neurons.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 5.
What is meant by nerve impulses?
Answer:
A nerve impulse is a series of electrical impulses which travel along with the nerve fibre.

Question 6.
What is meant by resting potential?
Answer:
The electrical potential difference across the plasma membrane of a resting neuron is called the resting potential.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 7.
What is meant by threshold potential?
Answer:
During depolarization when enough Na+ ions enter the cell the action potential reaches a certain level called threshold potential. (-55 mV)

Question 8.
What is threshold stimulus?
Answer:
The particular stimulus which is able to bring the membrane potential to the threshold is called the threshold stimulus.

Question 9.
What is meant by all or none principle?
Answer:
The action potential occurs in response to a threshold stimulus but does not occur at sub-threshold stimuli. This is called the all or none principle.

Question 10.
What is the cause of brain tumours?
Answer:

  • Glial cells: Nerve cells do not divide but glial cells do not lose the ability to undergo cell division.
  • So most brain tumours of neural origin consist of glial cells.

Question 11.
What are meninges?
Answer:
The brain is covered by outer Duramater, the median Arachnoid mater and the inner Piamater. These membranes are called meninges.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 12.
What is meant by lazy gate?
Answer:
During hyper polarization the K+ion gates are more permeable to K+ even after reaching threshold level it closes slowly hence called lazy gates.

Question 13.
What is spike potential?
Answer:
Due to the rapid influx of Na+ ions the membrane potential shoots rapidly up +45 mV which is called the spike potential.

Question 14.
What is meant by repolarisation?
Answer:
When the membrane reaches the spike potential the potassium ions K+ efflux from the axolemma and hence form negative potential. This is called repolarisation.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 15.
What is Hyper polarisation?
Answer:
If repolarisation becomes more negative than the resting potential -70 mV to about -90 mV it is called hyper polarisation.

Question 16.
Which decides the speed of the conduction of a nerve impulse?
Answer:

  • The conduction speed of a nerve impulse depends on the diameter of axon.
  • The greater the axon’s diameter the faster is the conduction.

Question 17.
What is septum pellucidum?
Answer:
A thin membrane which separates the lateral ventricles I and II is called the septum pellucidSamacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 18.
What is the difference between sub durai space and sub arachnoid space
Answer:

Sub durai space Sub arachnoid space
A narrow sub dural space present in between arachnoid and durameter The space between arachnoid membrane and piameter.

Question 19.
What is meant by sulcus and gyrus? What is its functions.
Answer:

  • Gyri – The convolution seen in the cerebrum.
  • Sulci – The shallow grooves increase the surface area of the cerebral cortex.

Question 20.
Name the lobes of cerebrum?
Answer:

  1. Pair of frontal
  2. Pair of parietal
  3. Pair of temporal
  4. Occipital

Question 21.
What is the function of proca?
Answer:
It involves in speech function.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 22.
What is meant by a blood brain barrier.
Answer:
It protects the brain by preventing many foreign substances in our vascular system from reaching the brain.

Question 23.
Which part of the cerebrum is called as sheet of emotions?
Answer:
The cortex of parietal occipital and temporal.

Question 24.
What is meant by motor area?
Answer:

  • The area which controls the voluntary muscular movements lies in the posterior part of the frontal lobes.
  • Functions They receive and interpret the sensory impulses.

Question 25.
What is the function of association area?
Answer:
They deal with memory communications learning and reasoning.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 26.
Where is pineal body situated? What is its functions?
Answer:

It is situated behind the choroid plexus the epithalamus forms short stalk
Functions
The melotoxin secreted by the pineal body regulates sleep wake cycle.

Question 27.
For a man to live all parts of the brain is important. How is brain divided into?
Answer:

  • Cerebrum
  • Thalamus
  • Hypothalamus
  • Pons
  • Cerebellum
  • Medulla oblongata

Question 28.
What is meant by corpus callosum?
Answer:
The two hemispheres of cerebrum is connected with the nerve band known as corpus callosum.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 29.
What is meant by brain stem? What are its parts?
Answer:
The region between spinal cord and diencephalon.

  1. Mid-brain
  2. Pons varoli
  3. Medulla oblongata

Question 30.
What is meant by corpora quadri gemina? What are its functions.
Answer:

  • The four papillae seen on the dorsal side of mid brain.
  • Perception of vision and hearing

Question 31.
What is meant by reflex arc?
Answer:

  • It is a fast involuntary unplanned sequence of actions that occurs in response to a particular stimulus.
  • The nervous elements that involved in carrying out reflex action constitute reflex arc.

Question 32.
What are the functions of cerebellum?
Answer:
The cerebellum controls and co-ordinates muscular movements and body equilibrium.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 33.
What is meant by receptors?
Answer:
The organ which made us aware of changes occur in our surrounding is called receptors.

Question 34.
What is meant by voluntary neural system?
Answer:
It is the part of the peripheral neural system associated with the voluntary control of body movements via skeletal muscles

Question 35.
Name the bacteriocidal substance present in the tears? Where is it seen? Name its secretion?
Answer:

  • Lysosome enzyme
  • Seen in tears.
  • Lacrymal glands. 1ml is secreted in a day.

Question 36.
What are mammillary bodies? What are its functions?
Answer:

  • The hypothalamus contains a pair of small rounded body called mammillary bodies.
  • Functions: It is involved in olfactory reflexes and emotional responses to odour.

Question 37.
What are cerebral peduncles?
Answer:
The region between diencephalon and the pons is called midbrain. It consists of a pair of longitudinal bands of nervous tissue called cerebral peduncles.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 38.
What is brain stem? What are its parts?
Answer:
It is the part of the brain between the spinal cord and the diencephalon.
Organs: Mid-brain, Pons, Medulla oblongata

Question 39.
What is caudo equina?
Answer:

  • After the 2nd lumbar vertebra the spinal nerves are greatly elongated
  • The thick bundle of elongated nerve roots appears as a horse’s tail called as cauda equina.

Question 40.
Where is enlargement region seen in the spinal cord?
Answer:

  • Cervical enlargement
  • Lumbar enlargement.

Question 41.
What is meant by reflex action?
Answer:

  • When a very quick response is needed the spinal cord can effect motor initiation as the brain and brings about an effect.
  • This rapid action by spinal cord is called reflex action.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 42.
What is meant by peripheral nervous system?
Answer:
All nervous tissue outside the CNS is the nervous system.

Question 43.
What is meant by mixed nerve?
Answer:
Each spinal nerve is a mixed nerve containing both afferent (sensory) and efferent (motor) fibers.

Question 44.
What is meant by pre ganglionic neuron?
Answer:
Its cell body is in the brain or spinal card. Its myelinated axon exits the CNS as part of cranial or spinal nerve and end in an autonomic ganglion.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 45.
What is autonomic ganglion?
Answer:
The axons of pre ganglionic neuron and cell bodies of post ganglionic neuron includes autonomic ganglion.

Question 46.
What is post ganglionic neuron?
Answer:
It conveys nerve impulses from autonomic ganglia to visceral effector organs.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 47.
What are the two branches of autonomous nervous system?
Answer:

  1. Sympathetic neural system
  2. Parasympathetic neural system.
  3. varying distances is called accommodation.

Question 48.
Give short notes on Lacrymal glands?
Answer:

  • The tear secreting glands are known as Lacrymal glands.
  • 1ml of tear is secreted in a day.
  • Tear salts, mucous and lysozyme enzyme to destroy bacteria.

Question 49.
What is conjunctiva?
Answer:
It is a thin protective mucous membrane found lining the outer surface of the eye ball.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 50.
Dilation and congestion of the blood vessels due to local irritation or infections. What is the disease? When will it occur?
Answer:

  • Conjunctivitis or madras eye.
  • Irritation or infection are the cause of blood shot eye.

Question 51.
What is sty?
Answer:
Infection of ciliary glands by bacteria causes a painful pus filled swelling called a sty.

Question 52.
What are the three types of cell present on the neural retina?
Answer:

  • Photo receptor cell
  • Cones
  • Rods
  • Bipolar and ganglion cells.

Question 53.
What is cataract?
Answer:
Due to the changes in nature of protein the lens become opaque called cataract.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 54.
What is aqueous humour and vitreous humour
Answer:

  • Aqueous humour – The fluid filled in between the cornea and iris.
  • Vitreous humour – Fluid filled in between lens and retina.

Question 55.
Give notes on lens fibres?
Answer:
Eye lens is transparent and biconvex made up of long columnar epithelial cells called lens fibre, these cells are formed of crystalline protein.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 56.
What are the three layers of eye ball?
Answer:

  1. Sclera – Outer coat
  2. Choroid – Pigmented middle layer
  3. Retina – Inner most layer

Question 58.
What is meant by maculae lutea?
Answer:
The yellow flat spot at the centre of the posterior region of the retina is called macula lutea. It is responsible for sharp detailed vision.

Question 59.
What is fovea centralis?
Answer:
A small depression present in the centre of the yellow spot is called fovea centralis which contains only cones.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 60.
What is blind spot?
Answer:
The optic nerves and the retinal blood vessels enter the eye slightly below the posterior pole whichis devoid of photoreceptors is called blind spot.

Question 61.
Why there is no cornea rejection during cornea transplantation?
Answer:

  • There is little or no possibility of cornea rejection.
  • This is because cornea does not have blood vessels.

Question 62.
What are the three ear ossicles?
Answer:

  1. Malleus – hammer bone
  2. Incus – anvil bone
  3. Stapes – stirrup bone

Question 63.
What are the three chambers of cochlea?
Answer:

  1. Scala vestibule
  2. Scala tympani
  3. Scala media

Question 64.
What is tectorial membrane?
Answer:
A roof like structure over hanging the organ of corti through out its length with the stiff gel membrane called tectorial membrane.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 65.
Name the receptors which are excited by airborne chemicals that dissolve in fluids?
Answer:
The receptors for taste and smell are the chemo receptors

Question 66.
What is tactile merkel disc?
Answer:
It is the light touch receptor lying in the deeper layer of epidermis.

Question 67.
What are the structures present in the membranous labyrinth?
Answer:

  • Cochlea
  • Vestibule
  • Semi circular canals

Question 68.
What are the three chambers of cochlea? Name the membrane which separates these chambers?
Answer:

  1. Scala vestibuli
  2. Scala tympanii
  3. Scala media

Separating membranes
Reisner’s membrane. It separates scala vestibuli from scala media
Basilar membrane. It separates scala media from scala tympani.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 69.
What is meant by stereo cilia?
Answer:

  • The organ of corti contains numerous hair cells on the basilar membrane.
  • Protruding from the apical part of each hair cell is hair like structures called stereo cilia.

Question 70.
What is proprioception?
Answer:
The ability to provide information about position and movements of the body is proprioception.

Question 71.
What is meant by vestibular system?
Answer:
This is the organ of balance this system is composed of fluid filled sacs and tubules.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 72.
Give notes on utriculus and sacculus?
Answer:
The utricle and saccule contain equilibrium receptor regions called maculae that are involved in detecting the linear movement of the head.

Question 73.
What is otolith?
Answer:

  • Maculae contains hair cells. These hair cells contain calcareous particles called otoliths.
  • It increases the inertia.

Question 74.
What are ampullae?
Answer:
At one end of each semicircular canal at its lower end has a swollen area called ampulla Each ampulla has sensory hair cells and supporting cells called crista ampullaris. The function is to detect rotational movement of the head.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 75.
Give the name of balancing structures which perform the following action.
a) Linear movement of the head
b) Changes occurring in body position.
c) Rotational movement of the head
Answer:

  • Maculae
  • Vestibular system
  • Crista ampularis

Question 76.
What is the unit of sound? Give notes on our ability of sound perception?
Answer:

  • The intensity of sound is measured in decibels. (dB)
  • 0-50 dB is the threshold of hearing for normal ear.
  • Prolonged exposure to sound with intensities greater than 90dB causes hearing loss.

Question 77.
What are chemo receptors?
Answer:

  • The receptors for taste and smell are the chemo receptors
  • The smell receptors are excited by air borne chemicals that dissolve in fluids.

Question 78.
What are olfactory organs? Where are they situated?
Answer:

  • The yellow coloured patches of olfactory epithelium form the olfactory organs.
  • They are located on the roof of the nasal cavity.

Question 79.
What are papillae?
Answer:
The tongue is provided with many small projection called papillae which is responsible for taste.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 80.
Give notes on taste buds.
Answer:

  • The taste bud cells are subjected to huge amounts of friction because of their location and are routinely burned by hot foods.
  • These are the most dynamic cells in the body and replaced every seven to ten days.

 

(3 Marks)

III. Short Answers

Question 1.
What are the three main functions of nervous system.
Answer:

  • Sensory functions: It receives sensory input from internal and external environment.
    Motor functions: It transmits motor commands from the brain to the skeletal and muscular system.
  • Autonomic functions: Reflex actions.

Question 2.
How do we classify neurons on the basis of its functions.
Answer:

  • Afferent neurons – That take sensory impulses to the central nervous system from the sensory organs.
  • Efferent neurons – That carry motor impulses from CNS to the effector organ.
  • Inter neurons – That lie entirely within the CNS between the afferent and efferent neurons.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 3.
What is meant by depolarisation?
Answer:

  • The inside of the axolemma becomes positively charged and negatively charged outside.
    This reversal of electrical charge is called depolarisation.

Question 4.
How is nerve impulses transmitted?
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 11

  • Inner to the axolemma the cytoplasm contains the infra cellular fluid with large amounts of potassium and magnesium phosphate with negatively charged proteins and other organic molecules.
  • Outside the axolemma contains large amounts of sodium chloride bicarbonates CO2 andmetabolic wastes
  • Due to the charged particles present in the inner and outside of the axolemma are responsible for the conduction of nervous impulses.

Question 5.
What is meant by repolarisation?
Answer:

  • When the axolemma reaches the spike potential the sodium voltage – gate closes and potassium – voltage gate opens.
  • It checks influx of Na+ ions and initiation the efflux of K ions which lowers the number of positive ions within the cell. Thus the potential falls back towards the resting potential.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 12

  • The reversal of membrane potential inside the axolemma to negative occurs clue to efflux of K+ ions. This is called repolarisation.

Question 6.
What is meant by hyper polarisation.
Answer:

  • If repolarisation becomes more negative than the resting potential -70 mV to about -90 mV.
    • It is called hyper polarisation. During this K+ ion gate are more permeable to K+ even after reaching the threshold level as it closes slowly hence called lazy gates.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 13

  • The membrane potential return to its original resting state when K+ ion channel close completely.
  • During hyper polarization the Na+ voltage gate remains closed.

Question 7.
Give an account of the conduction speed of a nerve impulse.
Answer:

  • If the axon’s diameter is greater the conduction will be faster.
  • The myelinated axon conducts the impulse faster than the non – myelinated axon.

Question 8.
What is meant by saltatory conduction?
Answer:
The myelinated axon conduction the impulse faster than the non – myelinated axon.
The voltage gated Na+ and K+ channels are concentrated at the nodes of Ranvier as a result the impulse jumps node to node. This is called saltatory conduction.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 9.
Give an account of the membranes (meninges) of brain?
Answer:
Brain is covered by three cranial meninges.

  1. The outer thicker layer is duramater which lines the inner surface of the cranial cavity.
  2. The inner most layer which is adhered to the brain is piameter.
  3. The median thin layer is arachnoid mater by a narrow subdural space.
  4. The piameter is separated from the arachnoid mater by the subarachnoid space.

Question 10.
List out the functions of brain lobes?
Answer:

Structure Function
Frontal Behaviour intelligence memory movement
Parietal Language reading sensation
Temporal Speech hearing memory
Occipital Visual processing

Question 11.
Why is thalamus considered as a important relay centre for impulse?
Answer:

  • It serves as a relay centre for impulses between the spinal and brain and cerebrum.
  • Information is sorted and edited.
  • It plays a key role in learning and memory.
  • It is a co-ordinating centre for sensory and motor signaling.

Question 12.
Why there may be a death due to the affectation of medulla oblongata?
Answer:

  • Medulla controls cardio-vascular reflexes respiration and gastric secretions.
  • If medulla is getting affected the circulation and respiration is affected.
  • That may cause a death of a person.

Question 13.
Give notes on mid brain?
Answer:

  • The midbrain is located between the diencephalon and the pons.
  • The lower portion of the mid-brain consists of a pair of longitudinal bands of nervous tissue called cerebral peduncles.
  • This relay impulses back and forth between cerebrum cerebellum pons and medulla.
  • The dorsal position of the mid Brain consist of four rounded bodies called corpora quadrigemina which acts as a reflex center for vision and hearing.

Question 14.
What are the features we develop when there is a functional deficiency of serotonin and nor epinephrine?
Answer:
Features:

  • negative mood
  • loss of interest
  • an in ability to experience pleasure
  • suicidal tendencies.

Drugs:
Anti depressant drug can treat all this features.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 15.
Give notes on cerebro spinal fluid?
Answer:

  • 150ml of cerebro spinal fluid is secreted in an adult.
  • 500ml of cerebro spinal fluid is secreted in a day.
  • Every 8 hours this fluid is rejuvenated.
  • Choroid plexux carries harmful metabolic wastes from the brain to the blood.

Question 16.
Based on their position how the receptors are classified?
Answer:
1. Exteroceptors – They are located at the surface of the body.
These senses the hearing vision touch taste and smell.

2. Introceptors: They are located in the visceral organs and blood vessels.
They are sensitive to internal stimuli.

3. Prerprioceptors:
They provide information about position and movements of the body.

Question 17.
Your friend is returning home after his visit to USA. All at home are waiting for his arrival.
How would you feel? State the division of ANS that predominates and mention few changes take place in your body?
Answer:

  • The sympathetic and parasympathetic neural system are is mainly involved.
  • On seeing his friend out of the happiness his autonomic nervous system is stimulated and he gets tears in his eyes.
  • After sometime the parasympathetic stops the secretion of tears.

Question 18.
What is meant by depression? What are its symptoms?
Answer:

  • Depression is a functional deficiency of serotonin and nor epinephrine.
  • This disorder is characterized by a pervasive negative mood, loss of interest an inability to experience pleasure and suicidal tendencies.

Question 19.
When dust falls on our eyes like eyelids close immediately not waiting for our willingness, on touching a hot pan the hand is with drawn rapidly. Do you know how this happens?
Answer:
Reflex axon.
When a very quick response is needed the spinal cord can effect motor initiation as the brain and brings about an effect it is due to fast action of spinal cord.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 20.
What are the differences between conditioned and unconditioned reflex.
Answer:

Unconditioned reflex Conditioned reflex
In born reflex for an unconditioned stimulus. It’s response to a stimulus acquired by learning.
It does not need any past experience or training Does not naturally exists in animals.
Eg: Blinking of an eye when a dust particle about to fall in it Eg: Excitement of salivary gland on seeing a food

Question 21.
What is the difference between exteroceptors and interoceptors.
Answer:

Exteroceptors Interoceptors
Located at or near the surface of the body They are located in the visceral organs and blood vessels.
These receive impulses from hearing vision touch taste and smell. They are sensitive to internal stimuli.

Question 22.
Where are lens fiber seen? What is the substance that fills it?
Answer:

  • The lens is a transparent biconvex structure made up of slender columnar epithelial cells.
  • These cells are called as lens fibre.
  • These cells are formed of crystaline protein.

Question 23.
What is meant by accommodation of eye? List the structures that are involved in this process?
Answer:

  • The ability of the eyes to focus objects at varying distances is called accommodation.
  • This is achieved by suspensory ligament ciliary muscle and ciliary body

Question 24.
Name the structures that helps in fixing eyes in the eye ball?
Answer:
Eye is held in its position with the help of six extrinsic muscles.
They are
Superior
Interior
Lateral
Median rectus muscle
Superior oblique
Inferior oblique

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 25.
Name the accessory structure which protects eye?
Answer:

  • Eye lashes and the eye brows
  • They help to protect the eyeballs from foreign objects, perspiration and from direct sunrays.
  • Sebaceous glands or ciliary glands.
  • They secrete a lubricating fluid.
  • Lacrymal glands.
  • Secrete tears.
  • Tears contain salts mucus and lysozyme enzyme to destroy bacteria.

Question 26.
Give an account of aqueous humour?
Answer:

  • It supplies nutrients and oxygen to the lens cornea and retinal cells.
  • It is produced and drained at same rate.
  • It maintains a constant infra ocular pressure of about 16 mmHg.

Question 27.
Give short notes on glaucoma.
Answer:
Any block in the canal of Schlemm increases the intra ocular pressure of aqueous humour and leads to “glaucoma when the optic nerve and the retina are compressed due to pressure.

Question 28.
Name the detects of detraction.
Answer:

  • Myopia
  • Hyper metropia
  • Astigmatism
  • Cataract

Question 29.
Give notes on pigments of colour vision
Answer:

  • Redcones. It contains visual pigment erythropsin which is sensitive to long wavelength close to 560 nm.
  • Green cones – It has a pigment chloropsin which is sensitive to medium wavelength of 530 nm.
  • Blue cones – It has a pigment which is sensitive to short wavelength of 420 nm.

Question 30.
What is the difference between conducting hearing loss and neuro sensory hearing loss.
Answer:

Conducting Hearing loss Neuro sensory
This defect is due to the blockage of ear canal with ear wax The defect may be in the organ of cortii
Rupture of ear The auditory nerve
Middle ear infection with fluid accumulation restriction of ossicular movement In the ascending auditory pathways or auditory cortex

Question 31.
Give short notes on melanin.
Answer:

  • Melanocytes synthesize melanin.
  • It gives colour to skin and protects it from the sun.
  • Vitiligo is a condition in which the melanin pigment is lost from the areas of the skin causing white patches.
  • The leukoderma appears when melanocytes fails to synthesis melanin pigment.

Question 32.
What is meant by the proprioception?
Answer:

  • Balance is part of a sense called proprioception.
  • It is the ability to sense the position orientation and movement of the body.

Question 33.
Which is the fastest renewable cells in the body? How is it affected?
Answer:
Taste buds

  • Taste buds are subjected to huge amounts of friction because of their location and are routinely burned by hot foods.
  • These cells are replaced every 7-10 days.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 34.
Name the disease which can affect people of any age gender or ethnic group. This is not the contagious disease?
Answer:
Leucoderma is a condition in which the melanin pigment is lost from areas of the skin causing white patches.

Question 35.
What are meissner’s corpuscles?
Answer:

  • These are small light pressure receptors found just beneath the epidermis in the dermal papillae.
  • They are numerous in hairless skin areas such as finger tips and soles of the feat.

(5 Marks)

IV. Brief Answers

Question 1.
Describe structure of a neuron.
Answer:
Neuron is composed of three region.

  1. Cell body
  2. Dendrites
  3. axon.

Cell body:
The cell body is spherical. There is no centriole.
The plasma membrane covering the neuron is called neurilemma and axon is axolemma.

Dendrites:
The repeatedly branched short fibres coming out of the cell bod dendrites which transmit impulses towards the cell body in it’s cytoplasm Nissl’s granules are present.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 14
Axon:
It is a long fibre that arises from a cone shaped area of the cell body. There is no golgi bodies and Nissis granules in its cytoplasm.
The axon of peripheral nerves is surrounded by Schwann’s cells to form myelin sheath. The myelin sheath is not continuous. There are gaps in the myelin sheath between an adjacent Schwann cells called nodes of Ranvier.
Each branch at the distal end of the axon terminates into a knob like structure called synaptic knob which possesses synaptic vesicles filled with transmitters. The axon transmits nerve impulses away from the body to neuro muscular junction. The myelinated nerve cell transmits impulses faster than non – myelinated nerve cells.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 2.
Describe about the different types of neuron with diagram?
Answer:
1. Multi polar neurons:
They have many processes with one axon and two or more dendrites.

2. Bipolar neurons:
They have two processes with one axon and one dendrites.
These are found in the retina of the eye, inner ear and the olfactory area of the brain.

3. Unipolar neurons:
They have a single short process and one axon.
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 15

Question 3.
Give an account of Ionic channels in the axolemma?
Answer:
Ionic channels:

  1. Leakage channels
  2.  Ligand – gated channels
  3. Voltage-gated channels.

1. Leakage channels:

    • These channels are always remain open.
    • K+ leakage channels are more in number than the Na+ leakage channels.
    • Sarco lemma has greater permeability to k+ icons than Na+ icons
    • These icons keep moving continuously to maintain the potential continuously to maintain the
    • potential difference across the axo lemma.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 16

2. Ligand – gated channels:
These are chemic called gated channels which open or close in response to a chemical stimuli.
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 17

  • They are located between the pre synaptic membrane of the first axon and post synaptic membrane of the second.
  • The neurotransmitter acetylcholine opens ligand channels that allow Na+ and Ca++ ions diffuse inward and K+ icon diffuse outward.

Voltage-gated channels:
Answer:
This channels open in response to a physical stimulus in the form of vibration such as touch and pressure.

  • Sodium Voltage gated channels.
  • Potassium Voltage gated channels.

Question 4.
Give an account of resting potential?
Answer:

  • The electrical potential difference across the plasma membrane of a resting neuron is called the resting potential.
  • More potassium is getting out of the neurilemma rather than sodium which is getting into.
  • Hence the interior of the cell becomes negative.
  • In resting condition the axon membrane is more permeable to K+ and less permeable to Na+ cons whereas it remains impermeable to negatively charged protein icons.
  • In the outer side of axon there is low concentration of K+ and high concentration of Na+ ions.
  • This difference can be maintained by ATP – driven sodium – potassium pump. This exchange 3 Na+ outwards for 2K+ in the cells.
  • In neuron the resting membrane potential ranges from 40mv to 90mv.
  • And its normal value is 70mv.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 5.
a) What is meant by action – membrane potential?
b) What is Depolarisation?
Answer:
a) An action potential occurs when a neuron sends information down an axon away from the cell body.
b) When a nerve fibre is stimulated sodium voltage gate opens and makes the axo lemma permeable to Na++ and the potassium voltage gate closes and potassium is getting out of the axo lemma. The concentration reduces
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 18

  • The axo lemma becomes positively charged inside and negatively charged outside.
  • This reversal of electrical charge is called depolarisation potential reaches level called threshold potential (-55mV)
  • The stimulus which bring this threshold potential is called threshold stimulus.
  • The action potential occur in response to a threshold stimulus but does not occur at subthreshold stimuli. This is called all or none principle.
  • Due to the rapid influx of Na+ ions the membrane potential shoots rapidly up to +45mV which is called the spike potential.

Question 6.
What is synapsis?
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 19

  • The junction between two neurons is called a synapses through which a nerve impulse is transmitted,
  • The first neuron involved in the synapse forms the pre synaptic neuron and the second neuron is the post – synaptic neuron
  • A small gap between the two neuron is synaptic cleft.
  • The axon terminals contain synaptic vesicles filled with neurotransmitters.
  • When an impulse arrives at the axon terminals it depolorizes the pre – synaptic membrane opening the voltage gated calcium channels.
  • Influx of calcium ions stimulates the synaptic vesicles toward the pre – synaptic membrane and fuse with it.
  • In the neurilemma the vesicles release their neurotransmitters into the synaptic cleft by exocytosis.
  • The released neurotransmitters bind to their specific receptors.
  • The entry of the ions can generate a new potential in the post synaptic neuron.
  • This excitatory post – synaptic potential causes depolarisation and in inhibitory post – synaptic potential causes hyperpolarisation.

Question 7.
In the following diagram indicate
Answer:
(A) – Frontal
(B) – parietal
(C) – occipital
(D) – temporal lobe
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 20

Question 8.
Describe the structure of human brain with a diagram?
Answer:

  • The brain is located in the cranial cavity and it is covered by three cranial membranes.
  • The outer layer — durameter the inner most layer piameter and the median thin layer arachnoid. The brain is divided into three major regions. Fore brain, Mid-brain, Hind

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 21

  • It comprises of cerebrum and diencephalon.
  • Tire cerebral cortex is composed of grey and unmyelinated nerve cells.
  • The medulla is composed of white mater.
  • The surface of the cerebrum shows many convolutions and grooves. The folds are called gyri and the shallow groove is sulci.

There are eight lobes in cerebrum.
A pair of frontals, parietals temporals and occipital lobes.
The longitudinal fissure divides the cerebrum | longitudinally into two hemispheres The hemispheres are connected by a tract of nerve fibres called corpus callosum.
Cerebral cortex has three functional areas

Sensory areas :
It occurs in the parietal temporal and occipital lobes of the cortex.

Motor areas :
This controls voluntary muscular movement which lies in the posterior part of the frontal iobes.

Association area :
It lies in between cortex and diencephalan This involves in memory communication learning and reasoning.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 9.
Describe the structure of hind brain?
Answer:
Rhombencephalon forms the hind brain.
It comprises of cerebellum pons varolii and medulla oblongata.

Cerebellum:
It is the second largest part of the brain. It consists of two cerebellar hemisphere and central worm shaped part the vermis.

Function:
It controls and coordinates muscular movements and body equilibrium.
Any damage to cerebellum results in unco-ordinated voluntary muscle movements.

Pons varoli:
It lies in between the midbrain and the medulla oblongata.
This form a bridge between the two cerebellar hemisphere and connect the medulla oblongata with the other region of the brain.

Medulla oblongata:
This forms the posterior most part of the brain. It connects the spinal cord with various parts of the brain.
It receives and integrates signals from spinal cord and sends it to the cerebellum and thalamus.

Function:
It controls cardiovascular reflexes respiration and gastric secretions.

Question 10.
Describe the structures of diencephalon?
Answer:
Epithalamus

  • It is a non – nervous tissue.
  • The anterior part of epithalamus is vascular and folded to form the anterior choroid plexus.
  • The epithalamus forms a short stalk which ends in a rounded body called pineal body.
  • This secretes the hormone melotonin which regulates sleep and wake cycle.

Thalamus

  • It is formed of grey matter
  • It serves as a relay centre for impulses between the spinal cord brain stem and cerebrum.
  • It plays a key role in learning and memory.
  • It is a major co-ordinating centre for sensory and motor signalling.

Hypothalamus

  • It forms the floor of the diencephalon.
  • It has a pair of small rounded body called mammillary bodies
  • It involves in olfactory reflexes and emotional responses to odour.
  • It maintains homeostasis.
  • It controls the body temperature.
  • Urge for eating and drinking.
  • It also contains a group of neuro secretory cells which secrete the hypothalamic hormones.
  • It also acts as the satiety centre.

Question 11.
Give an account of ventricles of the brain.
Answer:

  • The brain has four hollow fluid filled spaces.
  • The c – shaped space found inside each cerebral hemisphere forms the lateral ventricles I and II which are separated by a thin membrane called the septum pellucidum. Each lateral ventricle communicates with the III ventricle through opening called foramen of mortro.
  • The III ventricle opens in to the IV th ventricle through a canal called aqueduct of sylvius. Choroid plexus is a network of blood capillaries found in the root of the ventricles and forms cerebro spinal fluid.

Functions

  • CSF provides buoyancy to the CNS.
  • It acts as a shock absorber.
  • It nourishes the brain by supplying food and oxygen.
  • It carries harmful metabolic wastes from the brain to the blood.
  • It maintains a constant pressure inside the cranial vessels

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 12.
Differentiate the conditioned stimulus from unconditioned stimulus.
Answer:

Conditioned Unconditioned
1. Not through learning Acquired by learning
2. In born reflex It is not an in born reflex
3. It does not need any past experience Experience makes it a part of the behaviour
4. Eg: Blinking of an eye when a dust fall in to it. Eg: Secretion of salivary gland on seeing the food

Question 13.
Tabulate the nerves and functions and its nature of 6-12th cranial nerves.
Answer:

Cranial nerves Nature of nerve Function
I Olfactory nerve Sensory Sense of smell
II Optic nerve Sensory Sense of sight
III Oculomotor nerve Motor Movement of the eye
IV Trochlear nerve Motor Rotation of the eye ball
V Trigeminal nerve Sensory and motor (mixed) Functioning of facial parts
VI Abducens nerve Motor Rotation of the eye ball
VII Facial nerve Mixed Functioning of facial parts
VIII Auditory/ Vestibulocochlear nerve Sensory Maintains the equilibrium of the body/ Auditory function
IX Glossopharyngeal nerve Mixed Taste and touch
X Vagus Mixed Regulation of the visceral organs
XI Spinal accessory Motor Muscular movement of pharynx, larynx, neck and shoulder
XII Hypoglossal Motor Speech and swallowing

Question 14.
Tabulate the functions of sympathetic and para sympathetic nerve.
Answer:

Sympathetic nervous system Para sympathetic nervous system
1. It dialates pupil It constricts pupil of the eye
2. It inhibits the secretion of saliva It stimulates saliva secretion
3. It increases the heart beat It reduces the heart beat
4. It dialates bronches It constricts the bronchus
5. It inhibits digestion It stimulates digestion
6. It increases the glucose release It stimulates bile release
7. Stimulates epinephrine and nor epinephrine release It reduces the epinephrine and nor epinephrine release
8. Inhibits peristalsis and secretion Stimulates peristalsis and secretion
9. Reflexes bladder Contracts bladder

Question 15.
Describe the structure of cross section of spinal cord.
Answer:

  • There are two indentations the posterior median sulcus and the anterior median fissure.
  • In the spinal cord the grey matter forms an inner butterfly shaped region surrounded by the outer white matter.
  • The grey matter consists of dendrites inter neurons and guai cells.
  • White matter consists of bundles of nerve fibres.
  • Each half of the grey matter is divided into a
  • Dorsal horn – Cell bodies of inter neurons.
  • Ventral horn – Efferent motor neurons supplying the skeletal muscle.
  • Lateral horn – Nerves supply to heart smooth muscles exocrine glands. Originate from the cell bodies.
  • Ascending tract – This carry sensory impulses to the brain.
  • Descending tract – This carry motor impulses to brain.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 22

Question 16.
Give an account of the functional components of a reflex arc.
Answer:
Sensory receptor – It is a sensory structure that responds to specific stimulus.
Sensory neuron – This neuron takes the sensory impulse to the grey (afferent) matter of the
spinal cord through the dorsal root of the spinal cord.
Inter neuron – It may serve to transmit the impulses from the sensory neuron to the motor neuron.
Motor neuron – It transmits impulse from CNS to the effector organ
Effector neuron – It may be a muscle or gland which responds to the impulse received.
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 23

  • Lacrymal glands located in the upper lateral region of each orbit secrete tears.
  • Tears are secreted at the rate of 1 ml/day.
  • Tears contain salt mucus and lysozyme enzyme to destroy bacteria.
  • The protective mucus membrane present in the outer surface of the eye ball.
  • The eye has two compartments anterior and posterior compartments filled with aqueous humour and vitreous humour respectively.
  • The eye ball is consists of three layers sclera, vascular choroid and sensory retina.

Sclera

  • It consists of anterior cornea and the posterior sclera.
  • Cornea is composed of stratified squamous epithelium. Sclera forms the white of the eye and protects the eyeball.
  • At the junction of the sclera and the cornea is a channel called canal of schlemm which continuously drains out the excess of aqueous humour.

Choroid layer
It is highly vascularised pigmented layer.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 17.
Tabulate the differences between sympathetic and parasympathetic neural system.
Answer:

Sympathetic Neural System (SNS) Parasympathetic Neural System (PNS)
SNS originates in the thoracic and lumbar region of the spinal cord. PNS originates in the cranial region of the brain and the sacral region of the spinal cord.
Sympathetic ganglia are linked up to form a chain. Its ganglia remain isolated
Preganglionic fibres are short and the postganglionic fibres are long. Preganglionic fibres are long and the postganglionic fibres are short.
Noradrenaline is produced at the terminal ends of the postganglionic fibres at the effector organs. Hence the system is adrenergic. Acetylcholine is produced at the terminal ends of the postganglionic fibres at the effector organs. Hence the system is cholinergic.
Active during stressful conditions preparing the body to face them. Active during relaxing times restoring normal activity after a stress.
The overall effect is excitatory and stimulating. The overall effect is inhibitory.
It is considered as the flight or fight system. It is considered as “The rest and Digest System” or “The Feed and Breed System”.

Question 18.
Give an account of peripheral nervous system.
Answer:

  • All nervous tissue outside the central nervous system is the peripheral neural system.
  • It includes nerves ganglia enteric plexuses and sensory receptors.
  • Ganglia are sinai! masses of nervous tissue.
  • The neurons of these plexuses help in regulating the digestive system.
  • The specialised structure that helps to respond to changes in the environment are called sensory receptor.
  • This triggers nerve impulses along the afferent fibres to CNS.
  • PNS comprises of 12 pairs of cranial nerves and 31 pairs of spinal nerve.
  • The neural retina layer consists of cones and rods.
  • The yellow flat spot at the centre of the posterior region of the retina is called macula lutea.
  • A small depression present in the centre of the

Question 19.
Describe the structure of an eye.
Answer:

  • Eye is located in the orbit of the skull and held in its position with the help of six-extrinsic muscles.
  • Eye lashes and the eye brows help to protect the eyeballs.
  • Anteriorly the choroid thickens to form the ciliary body and coloured portion of the iris.
  • The aperture at the centre of the iris is the pupil through which the light enters.
  • The ability of the eyes to focus objects at varying distances is called accommodation which is achieved by suspensory ligament ciliary muscle and ciliary body.

Retina

  • It contains two region.
  • A sheet of non visual pigmented part neural visual region.
  • yellow spot is called fovea centralis which contains only cones.
  • The optic nerves and the retinal blood vessels enter the eye slightly below the posterior pole which is devoid of photo receptors called blind spot.

Question 20.
Draw the diagram of cross section of the eye.
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 24

Question 21.
Describe about the mechanism of vision.
Answer:

  • When light enters the eye it gets refracted by the cornea, aqueous humor and lens and it is focused on the retina and excites the rod and cone cells.
  • The rods and cones contain the retinal a derivative of vitamin A and the photo pigment opsin.
  • Light induces dissociation of retinal from opsin and causes the structural changes in opsin.
  • This generates an action potential in the photo receptor cells.
  • It is transmitted by the optic nerves to the visual cortex of the brain via the optic nerves for the perception of vision.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 25

Question 22.
List the refractive errors of eye.
Answer:
Myopia

  • The affected person cannot see distant objects.
  • As the eyeball is elongated or thickened lens the image of distant object is formed in front of the yellow spot.
  • This error can be corrected using concave lens.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 26

Hyper metropia

  • Affected person cannot see the nearby objects.
  • This is due to a shortened eyeball and thin lens. So the image of closest object is converged behind the retina.
  • This defect can be corrected by using convex lens.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 27

Presbyopia

  • Due to aging the lens loses elasticity and power of accommodation.
  • Convex lenses are used to correct this defect.

Astigmatism

  • It is due to the rough curvature of cornea or lens.
  • Cylindrical glasses are used to correct this error.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 23.
Describe the structure of an ear?
Answer:
Anatomically the ear is divided into three regions external ear middle ear and inner ear.
External ear:-

  • It consists of pinna external auditory meatus and ear drum.
  • The pinna collects the sound waves.
  • The external auditory meatus extends up to the tympanic membrane.
  • The tympanic membrane is covered with skin outside and with mucus membrane inside.

Middle ea:-

  • It is a air filled cavity in the temporal bone.
  • The middle ear contains three ossicles malleus incus and stapes.
  • The malleus is attached to the tympanic membrane and its head articulates with the incus.
  • The stapes is attached to the oval window in the inner ear.
  • The Eustachian tube connects the middle ear cavity with the pharynx

Inner ear:-

  • It is the fluid filled cavity consisting of two parts the bony labyrinth and the membranous labyrinths.
  • The bony labyrinth consists of three areas, cochlea, vestibule and semicircular canals.

a Cochlea is a coiled portion consist of 3 chambers namely.

  1. Scala vestibule
  2. Scala media
  3. Scala tympanii.

Scala vestibule and scala tympani are filled with peri lymph.
The scala media is filled with endo lymph.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 28

Question 24.
Describe the structure and functions of organ of cortii.
Answer:

  • Organ of corti is a sensory ridge located on the top of the basilar membrane.
  • Basilar membrane contains numerous hair cells that are arranged in four rows.
  • Protruding from the apical part of each hair cell is hair like structures known as stereocilia.
  • On the organ of cortii a stiff gel membrane called tectorial membrane is situated.
  • During the conduction of sound wave sterocilia makes contact with tectorial membrane.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 29

Question 25.
Give an account of mechanism of sound?
Answer:

  • Sound waves entering the external auditory meatus fall on the tympanic membrane and gets vibrated.
  • These vibrations are transmitted to the oval window through the three ear ossicles.
  • Since tympani membrane is 17-20 times larger than the oval windows. This pressure exerted on the oval window is about 20 times more than that on the tympanic membrane.
  • This pressure causes the round window to alternately bulge outward and inward mean while the basilar membrane along with the organ of corti move up and down.
  • These movements of hair alternately open and close the mechanically gated ion channel causes action potential.
  • This is propagated to the brain as sound sensation through cochlear nerve.

Question 26.
Differentiate the rods from cones.
Answer:

Rods Cones
1. Helps in seeing in dim light Colour perception in bright light
2. Contains Rhodopsin pigment Contains photopsin
3. The protein retinol and vitamins aldehyde combine to form scotoptin called Rhodopsin The protein opsin and retinol combines to form photopsin.
4. There are 120 million rods are seen on the retina 6-7 million cone cells are seen on the retina
5. Rods are seen richly over the surface of the foveal region. Cones are richly present on the foveal region.

Question 27.
A man is chating with his family in this time a house fly sits on his back at once he lifts the hand and strikes the fly. How can he know that? What are the structures involved in this perception?
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 30

  • The skin senses this skin is the largest sense organ.
  • All over the skin sensory receptors of pressure heat cold and pain.
  • Following are the sensory receptors of skin.

Tactile merkel disc

  • It is a light touch receptor lying in the deeper layer of epdidermis.
  • Hair follicle receptors. These are light touch receptors lying around the hair follicles.

Meissner’s corpuscles

  • These are small light pressure receptors found just beneath the epidermis in the dermal papillae.
  • They are numerous in hair less skin areas such as finger tips and soles of the feet.

Pacinian corpuscles

  • These are the large egg shaped receptors found scattered in the dermis.
  • It detects different textures temperature hardness and pain.

Ruffini endings
This lie in the dermis responds to continuous pressure Krause end bulbs are thermo receptors that sense temperature.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 28.
Give notes on Defects of ear.
Answer:

  • Deafness may be temporary or permanent
  • Conductive deafness
  • Possible causes
  • The blockage of ear canal with ear wax.
  • Rupture of ear drum.
  • Middle ear infection with fluid accumulation,
  • Restriction of ossicular movement.
  • Sensory-neural deafness
  • The defect may be in the organ of cortii or the auditory nerve or in the ascending auditory pathways or auditory cortex.

Question 29.
a) What is meant by proprioception?
b) Give an account of organs of equilibrium?
Answer:
The ability to sense the position orientation and movement of the body is called proprioception.
1. Vestibular system: This is the organ of balance.
It is composed of a series of fluid filled sacs contain endolymph and are kept in the surrounding peri lymph.

Semicircular canals

  • The canals that lie posterior and lateral to the vestibule are semi circular canals.
  • At each end of semi circular canal has a swollen area called ampulla.
  • Each ampulla has a sensory area known as crista ampullaris.
  • It detects the rotational movement of the head.

Question 30.
Give notes on Gustatory receptors?
Answer:

  • The sense of taste is considered to be the most pleasurable of all senses.
  • The tongue is provided with many small projections called papillae which gives the tongue an abrasive feel.
  • Most taste buds are located on the tongue few are scattered on the soft palate inner surface of the cheeks.

Structure
Taste buds are flask shaped and consists of 50 -100 epithelial cells of two major types.

  1. ustatory epithelial cells: Taste cells.
  2. Basal epithelial cells

Gustatory epithelial cells:

  • Long gustatory hairs project from the tip of the gustatory cells and extends through a taste pore senses the taste.
  • The sensory dendrites send signal to the brain and senses the taste.
  • The basal cells differentiates in to new gustatory cells.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination

Question 31.
Describe the structure of the receptor involved with a diagram.
Answer:

  • Taste buds are flask shaped. There are two major types.
  • Gustatory epithelial cells or taste cells.
  • Basal epithelial cells or repairing cells.
  • Long micro villi called gustatory hairs project from the tip of the gustatory cells and extends through a taste pore to the surface of the epithelium.
  • Gustatory hairs are tire sensitive portion of the gustatory cells and they have sensory dendrites which send the signal to the brain.
  • The basal cells that act as stem cells divide and differentiate into new gustatory cells.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 10 Neural Control and Coordination 31