neural control and coordination - 1 file download

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SECTION - A

Objective Type Questions

(Neuron, Nerve impulse and synapse)

1. Pseudounipolar neurons occur in

(1) Pyramidal cells of cerebral cortex (2) Retina of eye

(3) Schneiderian membrane (4) Cells of dorsal root ganglion

Sol. Answer (4)

Pseudounipolar neurons occur in the dorsal root ganglion of the spinal cord.

2. Which of the following act is responsible for the depolarisation of the neuron?

(1) Opening of voltage gated K+ channel (2) Opening of voltage gated Na+ channel

(3) Closure of voltage gated K+ channel (4) Closure of voltage gated Na+ channel

Sol. Answer (2)

The depolarisation of the neuron is due to the opening of voltage gated Na+ channels.

3. If the inside of neural membrane becomes more negative than – 70 mV it leads to

(1) Depolarisation (2) Repolarisation (3) Hyperpolarisation (4) Polarisation

Sol. Answer (3)

Due to opening of K+ channels for more time, increased K+ outflux occure leading to more negative potential

value than –70 mV inside membrane.

4. Suppose the terminal ends of axon are in contact with dendrites of four adjacent neurons, the nerve impulse

of the axon will

(1) Travel in all the four neurons

(2) Get distributed in all the four neurons resulting in a weak impulse

(3) Travel only in one neuron which is in closest contact and with the same intensity

(4) Travel in none of the neurons because the impulse travels from dendrites of one neuron into the axon of

another neuron

Sol. Answer (1)

Axon endings in the synapse release neurotransmitters which bind to the post-synaptic membrane, leading

to the transfer of either excitatory on inhibiting signals. So, when the neurotransmitter released by one

presynaptic neuron, strikes on the post–synaptic membrane next to it, nerve impulse will be generated

Chapter 8

Neural Control and Coordination

Solutions

Level - II

60 Neural Control and Coordination Solutions of Assignment (Level-II)


5. Axon endings release from its synaptic vesicles, a neuro-transmitter substance known as

(1) Acetylcholine (2) Acetylcholinesterases

(3) Inositol-3 phosphate (4) Diacylglycerol

Sol. Answer (1)

Acetylcholine is the neurotransmitter that is released from the synaptic vesicles.

(Central Neural System)

6. Which part are involved in movement of head to locate and detect the source of a sound?

(1) Superior colliculi (2) Inferior colliculi (3) Pons (4) Medulla oblongata

Sol. Answer (2)

Inferior colliculi is present inside the dorsal wall of the midbrain as the lower two round swellings. They receive

impulse from ears and the muscles of head and control the auditory reflexes.

7. Which part of the brain is like a defense castle controlling moods and plays an important role in emotional

behaviour, such as aggression and remembering fear?

(1) Hippocampus (2) Amygdala (3) Limbic system (4) Thalamus

Sol. Answer (2)

The emotional reaction such as aggression and fear is controlled by amygdala of the limbic system

Limbic system

Hippocampus(Controls signals of

smell and memories)

Amygdala(Controls anger and rage)

8. The link between paracoel and diocoel is through

(1) Foramina Luschka (2) Foramina Magendie (3) Foramen of Monro (4) Aqueduct of Sylvius

Sol. Answer (3)

Link between paracoel (cerebral hemispheres) and diacoel (diencephalon) is known as Foramen of Monro or

Interventicular foramen.

9. The function of choroid plexus is

(1) To produce lymph (2) To produce blood

(3) To produce cerebrospinal fluid (4) To produce endolymph

Sol. Answer (3)

The function of choroid plexus is to produce cerebrospinal fluid present inside the ventricles of brain and the

central canal of spinal cord.

61Solutions of Assignment (Level-II) Neural Control and Coordination


10. Branched tree like structure present in cerebellum is

(1) Arborial (2) Areole

(3) Arbor vitae (4) Archenteron

Sol. Answer (3)

Branched tree like, structures that is present in the cerebellum is known as Arbor vitae, which is formed by

white and grey matter.

11. The vomiting centre is situated in

(1) Cerebrum (2) Cerebellum

(3) Medulla (4) Hypothalamus

Sol. Answer (3)

Vomiting centre is located in the medulla oblongata.

12. End of spinal cord is

(1) Cauda equina (2) Conus terminalis (3) Filum terminalis (4) Funiculus

Sol. Answer (2)

End of the spinal cord is the conus terminalis.

Filum terminale = Fibrous tissue derived from piamater.

Cauda equina = Number of parallel spinal nerves in hinder part of spinal cord.

(Human Neural System)

13. The activity of which cranial nerve can protect us by warning about harmful chemicals in the air?

(1) V (2) IX (3) VI (4) X

Sol. Answer (1)

V. Trigeminal nerve – Smell (associated with nose)

IX. Glossopharyngeal – Taste and touch movements of Pharynx

VI. Abducens – Rotation of eyeball

X. Vagus nerve – Swallowing

Thus, activity of trigeminal nerve protects us by warning about harmful chemicals in the air

14. Paralysis of jaw muscles is due to loss of function of which cranial nerve?

(1) III (2) V (3) VII (4) X

Sol. Answer (2)

The trigeminal nerve (Vth nerve) controls the movement of jaw muscles. Loss of function of this nerve leads

to paralysis of the former muscles.

15. Which of the following cranial nerves in man is both sensory and motor?

(1) Optic (2) Olfactory (3) Trigeminal (4) Auditory

Sol. Answer (3)

Cranial nerves (12 pairs)

Motor nervesIII, IV, VI, XI, XII

Sensory nervesI, II, VIII

Mixed nerves(both sensory and motor)

V, VII, IX, X



16. Which of the following cranial nerves are linked with taste buds?

(1) VII & III (2) IX & II (3) IV & VIII (4) VII & IX

Sol. Answer (4)

Facial (VII) nerve and glossopharyngeal (IX) nerve are associated with the taste buds.

17. Smallest cranial nerve of the body is

(1) Trigemminal (2) Abducens (3) Opthalmic (4) Trochlear

Sol. Answer (4)

Trochlear (IV) nerve is the smallest cranial nerve while vagus (X) nerve is the largest cranial nerve.

18. The fourth cranial nerve of man is

(1) Abducens (2) Trochlear (3) Auditory (4) Oculomotor

Sol. Answer (2)

Abducens – VIth cranial nerve

Trochlear – IVth cranial nerve

Auditory – VIIIth cranial nerve

Oculomotor – IIIrd cranial nerve

19. The number of spinal nerves in man is

(1) 31 (2) 62 (3) 12 (4) 24

Sol. Answer (2)

There are 31 pairs (62) of cranial nerves

(Classification of sense organs and Taste Receptors)

20. The corpuscles lying deep in dermis and responsible for deep pressure are known as

(1) Pacinian corpuscles (2) Meissner’s corpuscles (3) Merkel’s discs (4) Ruffini’s endings

Sol. Answer (1)

Pacinian corpuscles are present deep in the dermis and responsible for deep pressure.

Meissner's corpuscles – Gentle pressure

Merkel's discs – Touch

Ruffini's endings – Heat

21. A molecule cannot be tasted or smelled until it has been

(1) Converted into protein (2) Converted into transmitter

(3) Grouped into multimolecular complex (4) Dissolved in a liquid

Sol. Answer (4)

A molecule cannot be tasted or smelled unless it is dissolved in the fluid because the dissolved chemical

comes in contact with the gustato receptors or olfactory receptors to initiate the depolarisation wave which

sends the impulse to the brain for interpretation of the taste sensation. The cilia, hair like receptors that extend

from cells inside the nose, are covered with thin, clear mucus that dissolves odor molecules not already in

vapour form.

22. Total number of taste buds in the human tongue is approximately

(1) 1000 (2) 10,000 (3) 1,00,000 (4) 50,000

Sol. Answer (2)

Total member of tastebuds in human tongue is approximately 10,000



(Eye)

23. When the object is at a distance of more than 6 metres, at that time

(1) Ciliary muscles are fully contracted (2) Convexity of lens is maximum

(3) Eyes are fully relaxed (4) All of these

Sol. Answer (3)

When object is at a distance of more than 6 metres i.e, have to see the distant object, ciliary muscles are

relaxed and suspensory ligaments are contracted leading to decrease in the convexity of lens while the eyes

are relaxing.

24. In old age when the vision of eye becomes dim due to deposits on lens, the condition is called

(1) Myopia (2) Hypermetropia

(3) Cataract (4) Astigmatism

Sol. Answer (3)

Cataract is a condition, more prevalent in old ages which is due to increase in the opacity of the lenses

Myopia : Eyeball is anterio-posteriorly elongated (Short sightedness)

Hypermetropia : Eyeball is anterio-posteriorly shortened (Farsighted)

Astigmatism : This disorder is due to rough curvature of cornea or lens

Cataract is the most common cause of vision loss in people over age 40 and is a principal cause of blindness

in the world.

25. In hypermetropia, the image is formed

(1) Before retina and is corrected by convex lens

(2) Behind retina and is corrected by convex lens

(3) Before retina and is corrected by concave lens

(4) Behind retina and is corrected by concave lens

Sol. Answer (2)

In hypermetropia, eyeball is anterio-posteriorly shortened, image is formed behind the retina and is corrected

by convex lens (Converging lens).

(A) Normal eye

Light focussedon retinaNear

object

(B) Hypermetropic eye

Light focussedbehind the retina

Nearobject



26. In Presbyopia

(1) The eye ball becomes short

(2) The lens become opaque

(3) The retina gets damaged

(4) Diminution of accommodation of lens due to loss of elasticity

Sol. Answer (4)

Presbyopia is a defect in the eyes of old age people due to loss of elasticity of lens and reduced power of

accommodation. Age related changes occur within the protein in the lens, making the lens harder and less

elastic over time. Age related changes also taken place in the muscle fibres surrounding the lens.

27. In myopia, light rays from far off objects converge

(1) Behind the retina (2) In front of the retina

(3) On the retina (4) In the retina

Sol. Answer (2)

Myopia : is a defect in which person is able to see the near object while is unable to see the far object. It

is corrected by concave lens (diverging lens) as it is due to elongation of anterio-posterior axis.

(A) Normal eye

far objectlight is focussed

on retina

(B) Myopic eye

far objectlight is focussedin front of retina

28. Overproduction of aqueous humour can result in

(1) Astigmatism (2) Fovea centralis

(3) Macula lutea or yellow spot (4) Glaucoma

Sol. Answer (4)

Glaucoma is caused by increased intraocular pressure (IOP) either due to increased secretion of aqueous humor

or blockage of the drainage canal which causes damage to the optic nerve.

29. Short sightedness or myopic vision is corrected by wearing

(1) Convex lenses

(2) Concave lenses

(3) Convex mirrors

(4) Concave mirrors

Sol. Answer (2)

Short sightedness or myopia in which the image is formed in front of the retina is corrected by wearing the

diverging on concave lenses



SECTION - B

Previous Years Questions

1. Which part of the brain is responsible for thermoregulation? [NEET-2019]

(1) Cerebrum (2) Hypothalamus (3) Corpus callosum (4) Medulla oblongata

Sol. Answer (2)

Hypothalamus in the thermoregulatory centre of our brain. It is responsible for maintaining constant body

temperature.

2. Which of the following statements is correct? [NEET-2019]

(1) Cornea is an external, transparent and protective proteinacious covering of the eye-ball.

(2) Cornea consists of dense connective tissue of elastin and can repair itself.

(3) Cornea is convex, transparent layer which is highly vascularised.

(4) Cornea consists of dense matrix of collagen and is the most sensitive portion the eye.

Sol. Answer (4)

Cornea consists of dense matrix of collagen and corneal epithelium. It is the most sensitive part of eye.

3. Which of the following structures or regions is incorrectly paired with its functions? [NEET-2018]

(1) Medulla oblongata : controls respiration and cardiovascular reflexes.

(2) Limbic system : consists of fibre tracts that interconnect different regions of brain; controls

movement.

(3) Corpus callosum : band of fibers connecting left and right cerebral hemispheres.

(4) Hypothalamus : production of releasing hormones and regulation of temperature, hunger and thirst.

Sol. Answer (2)

Limbic system is emotional brain. It controls all emotions in our body but not movements.

4. The transparent lens in the human eye is held in its place by [NEET-2018]

(1) ligaments attached to the ciliary body (2) ligaments attached to the iris

(3) smooth muscles attached to the ciliary body (4) smooth muscles attached to the iris

Sol. Answer (1)

Lens in the human eye is held in its place by suspensory ligaments attached to the ciliary body.

5. Myelin sheath is produced by [NEET-2017]

(1) Schwann Cells and Oligodendrocytes (2) Astrocytes and Schwann Cells

(3) Oligodendrocytes and Osteoclasts (4) Osteoclasts and Astrocytes

Sol. Answer (1)

Oligodendrocytes are neuroglial cells which produce myelin sheath in central nervous system while Schwann

cell produces myelin sheath in peripheral nervous system.

6. Receptor sites for neurotransmitters are present on [NEET-2017]

(1) Membranes of synaptic vesicles (2) Pre-synaptic membrane

(3) Tips of axons (4) Post-synaptic membrane

Sol. Answer (4)

Pre-synaptic membrane is involved in the release of neurotransmitter in the chemical synapse. The receptors

sites for neurotransmitters are present on post-synaptic membrane.



7. Good vision depends on adequate intake of carotene rich food. Select the best option from the following

statements [NEET-2017]

(a) Vitamin A derivatives are formed from carotene

(b) The photopigments are embedded in the membrane discs of the inner segment

(c) Retinal is a derivative of vitamin A

(d) Retinal is a light absorbing part of all the visual photopigments

(1) (a) & (b) (2) (a), (c) & (d) (3) (a) & (c) (d) (b), (c) & (d)

Sol. Answer (2)

Carotene is the source of retinal which is involved in formation of rhodopsin of rod cells. Retinal, a derivative of

vitamin A, is the light-absorbing part of all visual photopigments.

8. Choose the correct statements. [NEET (Phase-2)-2016]

(1) Nociceptors respond to changes in pressure

(2) Meissner's corpuscles are thermoreceptors

(3) Photoreceptors in the human eye are depolarised during darkness and become hyperpolarized in response

to the light stimulus

(4) Receptors do not produce graded potentials

Sol. Answer (3)

Photoreceptors (Rod cells) in human eye are depolarised during darkness and become hyperpolarised in

response to the light stimulus.

9. Photosensitive compound in human eye is made up of [NEET-2016]

(1) Transducin and Retinene (2) Guanosine and Retinol

(3) Opsin and Retinal (4) Opsin and Retinol

Sol. Answer (3)

Rhodopsin is made up of Retinal and opsin.

10. In mammalian eye, the 'fovea' is the center of the visual field, where [Re-AIPMT-2015]

(1) More rods than cones are found (2) High density of cones occur, but has no rods

(3) The optic nerve leaves the eye (4) Only rods are present

Sol. Answer (2)

11. Destruction of the anterior horn cells of the spinal cord would result in loss of [Re-AIPMT-2015]

(1) Integrating impulses (2) Sensory impulses

(3) Voluntary motor impulses (4) Commissural impulses

Sol. Answer (3)

12. A gymnast is able to balance his body upside down even in the total darkness because of [AIPMT-2015]

(1) Organ of corti (2) Cochlea (3) Vestibular apparatus (4) Tectorial membrane

Sol. Answer (3)

Vestibular apparatus is concerned with the maintenance of body balance. Both static as well as the dynamic

balance are maintained by vestibular apparatus.



13. Which of the following regions of the brain is incorrectly paired with its function? [AIPMT-2015]

(1) Cerebrum-calculation and contemplation

(2) Medulla oblongata-homeostatic control

(3) Cerebellum-language comprehension

(4) Corpus callosum-communication between the left and the right cerebral cortices

Sol. Answer (3)

The most important function of cerebellum seems to be coordinating locomotor actvity in the body.

14. Injury localized to the hypothalamus would most likely disrupt [AIPMT-2014]

(1) Short-term memory

(2) Co-ordination during locomotion

(3) Executive functions, such as decision making

(4) Regulation of body temperature

Sol. Answer (4)

Hypothalamus keeps the body temperature at roughly 37°C by means of a complex thermostat system.

15. Which one of the following statements is not correct? [AIPMT-2014]

(1) Retinal is the light absorbing portion of visual photo pigments

(2) In retina the rods have the photopigment rhodopsin while cones have three different photopigments

(3) Retinal is a derivative of Vitamin C

(4) Rhodopsin is the purplish red protein present in rods only

Sol. Answer (3)

Retinal is an aldehyde of vitamin A.

16. Parts A, B, C and D of the human eye are shown in the diagram. Select the option which gives correct

identification along with its functions/characteristics:

Lens

Iris

B

D

A

C

[NEET-2013]

(1) B – Blind spot – has only a few rods and cones.

(2) C – Aqueous chamber – reflects the light which does not pass through the lens.

(3) D – Choroid – its anterior part forms ciliary body.

(4) A – Retina – contains photo receptors – rods and cones.

Sol. Answer (4)



17. A diagram showing axon terminal and synapse is given. Identify correctly at least two of A-D.

A

B

C

D

[NEET-2013]

(1) B - Synaptic connection, D - K+ (2) A - Neurotransmitter, B - Synaptic cleft

(3) C - Neurotransmitter, D - Ca++ (4) A - Receptor, C - Synaptic vesicles

Sol. Answer (4)

18. The human hind brain comprises three parts, one of which is [AIPMT (Prelims)-2012]

(1) Cerebellum (2) Hypothalamus (3) Spinal cord (4) Corpus callosum

Sol. Answer (1)

The human brain has following different parts :

(a) ForebrainThalamus, hypothalamus

Cortex corpus striatum, limbic system

(b) Midbrain - Corpora quadrigemina

(c) Hindbrain - Pons, medulla, cerebellum

19. Which part of the human ear plays no role in hearing as such but is otherwise very much required?

[AIPMT (Prelims)-2012]

(1) Ear ossicles (2) Eustachian tube (3) Organ of Corti (4) Vestibular apparatus

Sol. Answer (4)

Vestibular apparatus is concerned with the balancing and equilibrium of the body.

20. A person entering an empty room suddenly finds a snake right in front on opening the door. Which one of the

following is likely to happen in his neuro-hormonal control system? [AIPMT (Prelims)-2012]

(1) Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal cortex

(2) Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal medulla

(3) Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse

(4) Hypothalamus activates the parasympathetic division of brain

Sol. Answer (2)

One seeing a snake, sympathetic nervous system releasing epinephrine and norepinephrine from adrenal

medulla cells of the adrenal gland.

21. The purplish red pigment rhodopsin contained in the rods type of photoreceptor cells of the human eye, is a

derivative of [AIPMT (Prelims)-2011]

(1) Vitamin A (2) Vitamin B1

(3) Vitamin C (4) Vitamin D

Sol. Answer (1)



22. When a neuron is in resting state i.e., not conducting any impulse, the axonal membrane is


(1) Comparatively more permeable to K+ ions and nearly impermeable to Na+ ions.

(2) Comparatively more permeable to Na+ ions and nearly impermeable to K+ ions

(3) Equally permeable to both Na+ and K+ ions

(4) Impermeable to both Na+ and K+ ions

Sol. Answer (1)

When neuronal membrane is at resting state it is more permeable to K+ ions while nearly impermeable to Na+

ions making the inside of the neuronal membrane more –ve than outside (+ve) outside.

At resting state : Na+ gated channels are in resting state and K+ gated channels are closed

23. The nerve centres which control the body temperature and the urge for eating are contained in


(1) Thalamus

(2) Hypothalamus

(3) Pons

(4) Cerebellum

Sol. Answer (2)

Hypothalamus controls the body temperature and urge for eating.

24. Select the answer with correct matching of the structure, its location and function. [AIPMT(Mains)-2010]

Structure Location Function

Equalizes air pressure sides of tympanic membrane

on either

Controls respiration ecretions

and gastrics

Controls body for eating and drinking

temperature, urge

Rods and cones are inactive here

present but

Anterior part of internal ear

Mid brain

Fore brain

Near the place nerve leaves the eye

where optic

(1) Eustachian tube

(2) Cerebellum

(3) Hypothalamus

(4) Blind spot

Sol. Answer (3)



25. Which part of human brain is concerned with the regulation of body temperature? [AIPMT (Prelims)-2009]

(1) Cerebellum (2) Cerebrum (3) Hypothalamus (4) Medulla Oblongata

Sol. Answer (3)

Hypothalamus :-

(a) Regulation of body temperature

(b) Hunger and thirst

(c) Secretion of hormones e.g., oxytocin, ADH etc.

26. Given below is a diagrammatic cross-section of a single loop of human cochlea. Which one of the following

options correctly represents the names of three different parts? [AIPMT (Prelims)-2008]

(1) A – Perilymph, B – Tectorial membrane, C – Endolymph

(2) B – Tectorial membrane, C – Perilymph, D – Secretory cells

(3) C – Endolymph, D – Sensory hair cells, A – Serum

(4) D – Sensory hair cells, A – Endolymph, B – Tectorial membrane

Sol. Answer (1)

(a) Perilymph (b) Tectoral membrane

(c) Endolymph (d) Sensory hair cells on basilar membrane

27. During the propagation of a nerve impulse, the action potential results from the movement of


(1) Na+ ions from extracellular fluid to intracellular fluid

(2) K+ ions from extracellular fluid to intracellular fluid

(3) Na+ ions from intracellular fluid to extracellular fluid

(4) K+ ions from intracellular fluid to extracellular fluid

Sol. Answer (1)

During depolarisation/propagation of nerve impulse results from movement of Na+ ions from extracellular fluid

to inside the axolemma



28. Which one of the following pairs of structures distinguishes a nerve cell from other types of cell?


(1) Nucleus and mitochondria (2) Perikaryon and dendrites

(3) Vacuoles and fibers (4) Flagellum and medullary sheath

Sol. Answer (2)

29. During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma

membrane has which type of electric charge? [AIPMT (Prelims)-2007]

(1) First positive, then negative and again back to positive

(2) First negative, then positive and again back to negative

(3) First positive, then negative and continue to be negative

(4) First negative, then positive and continue to be positive.

Sol. Answer (2)

During resting state the potential of the inner side of the axolemma is negative which during depolarisation

turned +ve due to influx of Na+ ions and during repolarisation turns again –ve due to opening of K+ channels.

30. Which one of the following is an example of negative feed back loop in humans?


(1) Secretion of sweat glands and constriction of skin blood vessels when it is too hot.

(2) Constriction of skin blood vessels and contraction of skeletal muscles when it is too cold.

(3) Secretion of tears after falling of sand particles in to the eye

(4) Salivation of mouth at the sight of delicious food.

Sol. Answer (2)

31. Bowman’s glands are located in the [AIPMT (Prelims)-2007]

(1) Olfactory epithelium of our nose (2) Proximal end of uriniferous tubules

(3) Anterior pituitary (4) Female reproductive system of cockroach

Sol. Answer (1)

32. Which one of the following statements is correct? [AIPMT (Prelims)-2006]

(1) Neurons regulate endocrine activity, but not vice versa

(2) Endocrine glands regulate neural activity and nervous system regulates endocrine glands

(3) Neither hormones control neural activity nor the neurons control endocrine activity

(4) Endocrine glands regulate neural activity, but not vice versa

Sol. Answer (2)

33. Which one of the following not act as a neurotransmitter? [AIPMT (Prelims)-2006]

(1) Acetylcholine (2) Epinephrine (3) Nor epinephrine (4) Cortisone

Sol. Answer (4)

Cortisone is not secreted by neurosecretory cells; it is secreted by cells of adrenal gland hence they are

hormonal secretions, not neurotransmitters. Acetylcholine, norepinephrine and epinephrine are secreted by the

cyton of neuron and deposited in synaptic vesicles in the synaptic knob to act as neurotransmitter



34. Bowman’s glands are found in [AIPMT (Prelims)-2006]

(1) Olfactory epithelium (2) External auditory canal

(3) Cortical nephrons only (4) Juxtamedullary nephrons

Sol. Answer (1)

35. In a man, abducens nerve is injured. Which one of the following functions will be affected?


(1) Movement of the eye ball (2) Swallowing

(3) Movement of the tongue (4) Movement of the neck

Sol. Answer (1)

Abducens (VIth cranial) nerve innervates external rectus muscles of eye, rotation of eyeball.

36. One of the examples of the action of the autonomous nervous system is [AIPMT (Prelims)-2005]

(1) Knee-jerk response (2) Pupillary reflex

(3) Swallowing of food (4) Peristalsis of the intestines

Sol. Answer (2)

37. Parkinson’s disease (characterized by tremors and progressive rigidity of limbs) is caused by degeneration of

brain neurons that are involved in movement control and make use of neurotransmitter


(1) Acetylcholine (2) Norepinephrine

(3) Dopamine (4) GABA

Sol. Answer (3)

Disease Cause

Parkinson's disease - ↓Dopamine

Huntington's chorea - ↓ GABA

Alzheimer's disease - ↓ Acetylcholine

38. Poisons like cyanide inhibit Na+ efflux and K+ influx during cellular transport. This inhibitory effect is reversed by an

injection of ATP. This demonstrates that

(1) ATP is the carrier protein in the transport system (2) Energy for Na+-K+ exchange pump comes from ATP

(3) ATP is hydrolysed by ATPase to release energy (4) Na+-K+ exchange pump operates in the cell

Sol. Answer (2)

Inhibition effect on Na+ efflux and K+ influx during cellular transport was reversed by ATP injection. This shows

that energy from Na+ –K+ exchange comes form ATP.

39. In the resting state of the neural membrane, diffusion due to concentration gradients, if allowed, would drive

(1) K+ into the cell (2) K+ and Na+ out of the cell

(3) Na+ into the cell (4) Na+ out of the cell

Sol. Answer (3)

In normal conditions the extracellular concentration of Na+ is high so if allowed at resting state the excess

Na+ ions will travel inside down the concentration gradient



40. Alzheimer’s disease in humans is associated with the deficiency of

(1) Gamma aminobutyric acid (GABA) (2) Dopamine

(3) Glutamic acid (4) Acetylcholine

Sol. Answer (4)

41. Which cranial nerve has the highest number of branches?

(1) Vagus nerve (2) Trigeminal

(3) Facial nerve (4) None of these

Sol. Answer (1)

Vagus nerve (Xth cranial nerve) has the highest number of branches, it supplies the neurons to organs like larynx,

lungs, pharynx, heart, oesophagus, stomach, intestine, blood vessels of abdomen, liver, pancreas, colon.

42. Injury to vagus nerve in humans is not likely to affect

(1) Tongue movements (2) Gastrointestinal movements

(3) Pancreatic secretion (4) Cardiac activity

Sol. Answer (1)

Vagus nerves (X), injury does not affect tongue movement because it does not innervate the tongue.

43. The sympathetic nerves, in mammals, arise from

(1) Sacral nerves (2) 3rd, 7th, 9th and 10th cranial nerves

(3) Thoracico-lumbar segments of spinal cord (4) Cervical nerves

Sol. Answer (3)

Sympathetic neurons in mammals arise from thoracico lumbar segments of spinal cord (T1t0L

3)

44. Sympathetic nervous system induces

(1) Secretion of digestive juices (2) Increase in heart beat rate

(3) Secretion of saliva (4) All of these

Sol. Answer (2)

Secretion of saliva & digestive juices is by parasympathetic nervous system.

45. Post–ganglionic fibre of sympathetic nervous system connected with sweat gland secrete

(1) Adrenaline (2) Epinephrine (3) Acetylcholine (4) GABA

Sol. Answer (3)

Post ganglionic fibre of sympathetic neurous system connected with sweat gland secrete acetylcholine

46. Which of following is not the action of sympathetic nervous system?

(1) Dilation of pupil

(2) Storage of bile in the gall bladder

(3) Constriction of peripheral arteries

(4) Contraction in the wall of urinary bladder

Sol. Answer (4)

Contraction in the wall of urinary bladder is controlled by parasympathetic neuron.



47. Which of the following is not the action of sympathetic nervous system?

(1) Slows down peristalsis (2) Erection of hair

(3) Contraction in gall bladder (4) Constrict arteries and raises blood pressure

Sol. Answer (3)

Contraction of gall bladder secretion of bile leading to the digestion of the lipid is a function of parasympathetic

nervous system.

48. Rate of conduction of impulse will be faster in case of

(1) Myelinated nerve fibre (2) Thicker nerve fibre (3) Non-myelinated nerve fibre (4) Both (1) and (2)

Sol. Answer (4)

In myelinated fibre, impulse travesl from node to node.

Rate of conduction of impulse is faster in case of myelinated and thicker neurons.

49. If the ligament directly below the kneecap is struck lightly by the edge of the hand or by a doctor’s rubber hammer,

knee jerk reflex occurs. This stretch reflex is

(1) Polysynaptic (2) Withdrawl (3) Monosynaptic (4) Bisynaptic

Sol. Answer (3)

Knee-jerk reflex is monosynaptic and does not involve interneurons, only single synapse is found.

50. Which of the following is not a part of knee jerk reflex?

(1) Afferent pathway (2) Muscle spindle

(3) Efferent pathway (4) Interneuron

Sol. Answer (4)

Knee jerk reflex is an example of monosynaptic reflex and does not involve interneuron

51. Pacinian corpuscles which occur in the skin are

(1) Free sensory nerve endings

(2) Specialised cells at the end of the sensory nerve fibre

(3) A type of gland

(4) Encapsulated pressure receptors deep in the dermis

Sol. Answer (4)

Pacinian corpuscle : Encapsulated, pressure sensing receptor, present deep in the dermis.

Free sensory nerve endings : Pain

52. Which of the following is located in deeper parts of skin and is sensitive to pressure?

(1) Meissner's corpuscles (2) Merkel’s disc

(3) Pacinian corpuscles (4) Ruffini's corpuscles

Sol. Answer (3)

Pacinian corpuscle - pressure

Meissner’s corpuscleMerkel's disc

touch

Ruffinis corpuscle - hot/heat



53. Highly vascular and closely inverting protective coat around brain is known as

(1) Arachnoid (2) Piamater

(3) Duramater (4) Sub-arachnoid space

Sol. Answer (2)

Piamater - Innermost, highly vascular

Duramater - Outermost, fibrous

Arachnoid - Middle, thin

54. The ability to hear often decreases with age because

(1) The cilia degenerate (2) The hair cell stiffen

(3) The flexibility of the basilar membrane changes (4) The tympanic canal straightens

Sol. Answer (3)

The ability of hearing decreases with age is due to change in flexibility of basilar membrane and is known as

Presbycusis

55. Helicotrema connects

(1) Scala vestibuli and scala tympani filled with endolymph

(2) Scala vestibuli and scala media filled with perilymph

(3) Scala vestibuli and scala tympani filled with perilymph

(4) Scala media and scala tympani filled with endolymph

Sol. Answer (3)

Helicotrema connects scala vestibuli to scala tympani filled with perilymph.

56. Which of the following part in ear is filled with endolymph?

(1) Scala vestibuli (2) Scala tympani (3) Median canal (4) Helicotrema

Sol. Answer (3)

Median canal (scala media) contains endolymph

57. At the time of flight, the pain in the ear is due to

(1) Sound of the engine

(2) Difference in pressure between the middle and inner ear

(3) Difference in pressure between the middle and outer ear

(4) Opening of eustachian tube

Sol. Answer (3)

At the time of flight, at high altitude air pressure difference between outer and middle ear cause pain.

58. The membrane that gives us the ability to discriminate different pitches of sound is the

(1) Round window

(2) Tympanic membrane

(3) Tectorial membrane

(4) Basilar membrane



Sol. Answer (4)

The basilar membrane is responsible for identifying various pitches of sound.

The basilar membrane has different flexibility in the proximal (A) to distal (B) position, resulting in sensation

of different pitches.

59. Cornea transplant in humans is almost never rejected. This is because

(1) It is a no-living layer (2) Its cells are least penetrable by bacteria

(3) It has no blood supply (4) It is composed of enucleated cells

Sol. Answer (3)

Cornea has no blood supply, so transplant is always successful.

60. Which of the following is correct w.r.t. differences between Rod Cells and Cone Cells of our retina?

Rod Cells Cone Cells

(1) Distribution More concen-trated in

centre of retina

Evently distributed all over

retina

(2) Visual acuity High Low

(3) Visual pigment

contained

Iodopsin Rhodopsin

(4) Overall function Vision in poor light Colour vision and detailed

vision in bright light

Sol. Answer (4)

Rod Cells Cone Cells

(a) Absent in centre of retina i.e, fovea centralis - More concentrated in central part of retina

(b) Visual activity is less - High

(c) Rhodopsnin pigment - Iodopsin

(d) Vision in poor light - Vision in bright light

61. In the chemistry of vision in mammals, the photosensitive substance is called

(1) Rhodopsin (2) Melanin

(3) Sclerotin (4) Retinol

Sol. Answer (1)

Rhodopsin is the photosensitive pigment in mammals



62. Which food should be eaten in case of deficiency of rhodopsin in eyes?

(1) Carrot and ripe papayas (2) Guava, Banana

(3) Mango, Potato (4) None of these

Sol. Answer (1)

Carrot and papaya are rich source of vitamin A (retinol)

oxidisesRetinol retinal⎯⎯⎯⎯⎯→

Retinal is a constituent of rhodopsins

Rhodopsin ⎯⎯→ retinal + opsin (protein)

Rhodopsin is a visual pigment in mammals

63. When we migrate from dark to light, we fail to see for sometime but after a time, visibility becomes normal.

It is example of

(1) Accommodation (2) Adaptation

(3) Mutation (4) Photoperiodism

Sol. Answer (2)

When we move from dark to light,

dissociationRhodopsin retinal + opsin⎯⎯⎯⎯⎯→

Which gives sensation to optic nerve and further to brain for processing. This reaction (above) is not irreversible.

It again combines to form rhodopsin and is known as adaptation.

64. Which of the following keeps our body temperature at roughly 37°C by means of a complex thermostat system?

(1) Somatosensory area (2) Hypothalamus

(3) Basal ganglia (4) Cerebellum

Sol. Answer (2)

Hypothalamus is responsible for maintaining thermostat of the body and keeps temperature of the body at 37ºC.

65. Match the column I with column II

Column-I Column-II

a. Horizontal and amacrine cell (i) Pivot point

b. Incus (ii) Olfactory epithelium

c. Bowman’s gland (iii) Retina

d. Cupula (iv) Crista

(v) Macula

(1) a(iv), b(v), c(ii), d(iii) (2) a(i), b(ii), c(iii), d(iv)

(3) a(iii), b(i), c(ii), d(iv) (4) a(iii), b(i), c(ii), d(v)

Sol. Answer (3)

Horizontal and amacrine cells – retina

Malleus–incus – Pivot joint

Bowman's gland – Olfactory epithelium

Cupula – Crista



66. Human eye is adjusted for distant objects more than 6 m away. For seeing the near objects which of the following

would not occur?

(1) Contraction in circular ciliary muscle

(2) Slackening of suspensory ligaments

(3) Radius of curvature of lens decreases

(4) Decrease in curvature of the lens

Sol. Answer (4)

For seeing the nearer objects

(a) Curvature of lens increases

Lens

Ciliarybody

Suspensory ligament

ImageObject(Near , (6m)i.e

(b) Ciliary body contracts

(c) Suspensory ligament relaxes.

67. Ora serrata is

(1) Centre point of macula lutea

(2) Area devoid of receptor cells

(3) Area between sensory and non-sensory part of retina

(4) Part of choroid adjacent to retina possessing light reflecting guanine crystals

Sol. Answer (3)

Ora serrata is the section of retina which present between and non-sensory portions

68. The cornea is very important component of the human eye. The main function of it is to

(1) Change the shape of the lens to enable the image to be focused on the retina

(2) Provide structural support to the eye

(3) Absorb the O2 from atmosphere

(4) Refract the light towards the retina, helps in maximum focussing

Sol. Answer (4)

Cornea's primary function is to refract light waves to converge on retina.

SECTION - C

Assertion-Reason Type Questions

1. A : In the nervous system, generation of action potential depends upon influx of sodium ions into axoplasm.

R : Influx of sodium ions during nerve impulse generation is due to efflux of potassium ions.

Sol. Answer (3)

In nervous system, generation of action potential is due to influx of sodium ions through voltage gated Na+

channels.

2. A : Presence of myelin sheath increases the rate of conduction of nerve impulse.

R : Ionic channels are completely completely absent in the area covered by myelin sheath therefore,

depolarization occurs only at the nodes of Ranvier, resulting in saltatory or jumping conduction.

Sol. Answer (3)

Presence of myelin sheath causes faster conduction due to saltation. Ionic channels are lesser in number is

regions in between nodes of Ranvier and concentrated more in node of Ranvier.



3. A : Receptors in the tendon at joints give information regarding the position and movements of different parts

of the body.

R : These are termed as noci-receptors.

Sol. Answer (3)

Receptors present in tendon, ligaments joints give information regarding different body parts and called

proprioceptors. Noci-receptors are pain receptors.

4. A : Sharpest vision is in fovea centralis in human eye.

R : The relationship of receptor to bipolar cells to ganglion cells is 1 : 1 : 1 within fovea centralis.

Sol. Answer (2)

Fovea centralis is the area of most acute vision of retina and here the ratio of rods, cones and bipolar cells

and ganglion cells is 1:1:1. This acute vision is due to high number of cones in the fovea centralis.

5. A : Postganglionic nerve fibre of parasympathetic nervous system have acetylcholine while sympathetic nervous

system have adrenaline as the neurotransmitter.

R : Sympathetic nervous system inhibit the intestinal peristalsis while parasympathetic stimulate peristalsis.

Sol. Answer (2)

Parasympathetic nervesPostganglionic

Acetylcholine

neuronsrelease

Sympathetic Nerves Epinephrine

Sympathetic system inhibits peristalsis of intestine while parasympathetic system enhances it

6. A : Transmission of the nerve impulse across a synapse is accomplished by neurotransmitters.

R : Transmission across a synapse usually requires neuro-transmitters because there is small space, i.e.,

synaptic cleft, that separates one neuron from another.

Sol. Answer (1)

Transmission of nerve impulses across a synaptic cleft (a small space separating two (10 – 20 mm, neurons),

occurs with the help of neurotransmitters due to presence of space, this is known as chemical synapse while

in the electrical synapse ( � 5nm) does not require neuro transmitter due to low space.

7. A : Sense organs, do not interpret the stimulus, it is done by brain.

R : Sense organs are transducers and they transform the energy of a stimulus to the energy of nerve impulses.

Sol. Answer (1)

Sense organs act as transducers, they transform the sensation into nerve impulse and transmit via sensory

neuron to the brain where the association and interpretation of the sensation occurs in their respective sensory

areas.

8. A : The imbalance in the concentration of Na+, K+ and proteins generates the resting potential.

R : To maintain the unequal distribution of Na+ and K+, neurons use electrical energy.

Sol. Answer (3)

The imbalance of K+, Na+ and proteins cause resting membrane potential and during resting membrane, the

resting potential is due to transfer of K+ ions down the concentration gradient inside the axolemma and Na+,

voltage gated channels are closed.



9. A : Retina is arranged anatomically in reverse order from what might be expected.

R : The receptor cells are, towards the outside and ganglionic cells towards the inside and light must pass

through the nerve cells to reach them.

Sol. Answer (1)

Retina is arranged anatomically such that light passes through nerves then to inner photosensitive cone and

rod cells

10. A : The brain reaches between 75 and 80 per cent of adult size within the first two years, and its full size at

the age of 6 years.

R : From evolutionary point of view, human gestation period is belived to be shortening.

Sol. Answer (2)

Brain reaches 75 – 80% of adult size by the age of two and full size at the age of 6 year With evolution the

gestation period is believed to be reducing.

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