21

Q1. The 5th cranial nerve of frog is called  

• Optic nerve  
• Vagus  
• Trigeminal  
• Ophthalmic  

Solution

The 5th cranial nerve of frog is called the trigeminal nerve. It is the largest cranial nerve arising from the medulla oblongata.  

Q2. The purplish red pigment rhodopsin contained in the rod type of photoreceptor cells of the human eye is a derivative of

• Vitamin B₁
• Vitamin C
• Vitamin D
• Vitamin A

Solution

Rhodopsin, a visual purple pigment, is a derivative of vitamin A.

Q3. Which one feature is common to leech, cockroach and scorpion?  

• Nephridia  
• Ventral nerve cord  
• Cephalisation  
• Antennae  

Solution

The central nervous system of leech, cockroach and scorpion has a double, ventral and solid nerve cord.  

Q4. Colour blindness is due to a defect in  

• Cones  
• Rods  
• Rods and cones  
• Rhodopsin  

Solution

Colour blindness is the inability to see colours. Lack of one or more types of cone cells causes colour blindness.  

Q5. The _____________ is also known as membranous labyrinth

• Inner ear
• Middle ear
• External ear
• External ear and middle ear

Solution

The inner ear is also known as membranous labyrinth

Q6. The electrical potential difference between outside and inside of a nerve axon before excitation is known as

• Resting potential
• Action potential
• Spike potential
• Reaction potential
• Activation potential

Solution

The electrical potential difference across the resting plasma membrane is called a resting potential.

Q7. An action potential in the nerve fibre is produced when positive and negative charges on the outside and the inside of the axon membrane are reversed because

• more potassium ions enter the axon as compared to sodium ions leaving it
• more sodium ions enter the axon as compared to potassium ions leaving it
• all potassium ions leave the axon
• all sodium ions enter the axon

Solution

When a nerve fibre is stimulated, its membrane becomes more permeable to sodium ions. Hence, more sodium ions enter the axon than potassium ions leaving it. As a result, the positive and negative charges on the outside and inside of the membrane are reversed.

Q8. Which of the following nerves is purely a motor nerve?  

• Vagus  
• Facial  
• Abducens  
• Trigeminal  

Solution

Abducens is a motor nerve which controls the movement of the eyeball. Vagus, facial and trigeminal are mixed nerves.  

Q9. The middle ear consists of

• Ear ossicles and eustachian tube
• Eustachian tube and tympanum
• Ear ossicles and tympanum
• Tympanum, Eustachian tube and ear ossicles

Solution

Middle ear contains ear ossicles and eustachian tube

Q10. The wax gland present in the ear canal is called

• Sweat gland
• Prostate gland
• Cowper's gland
• Sebaceous gland/ceruminous gland

Solution

Wax glands present in the ear canal are called sebaceous glands or ceruminous glands. They secrete a brownish, semisolid, fatty substance called wax or cerumen.

Q11. The Nissl's granules of nerve cell are made up of

• ribosomes
• protein
• DNA
• RNA

Solution

Nissl's granules are the groups of ribosomes and rough endoplasmic reticulum. They are involved in synthesis of proteins.

Q12. Which of the following equalizes air pressure on either sides of ear drum?

• Pinna
• Round window
• Eustachian tube
• Oval window

Solution

Eustachian tube equalizes air pressure in the sides of ear drum

Q13. The myelin sheath is derived from  

• Neuroglial cells  
• Schwann cells  
• Nerve cells  
• All of the above  

Solution

In myelinated nerve fibres, the myelin sheath is derived from Schwann cells. It is present around the axon.  

Q14. Protein found in the eye lens is  

• Crystallin  
• Collagen  
• Opsin  
• Rhodopsin  

Solution

Crystallin is a water-soluble protein present in the eye lens and cornea of the eye.  

Q15. The human hindbrain comprises three parts, one of which is the

• Spinal cord
• Corpus callosum
• Cerebellum
• Hypothalamus

Solution

Cerebellum, pons and medulla oblongata are the three parts of the hindbrain.

Q16. Telescopic vision is found in

• Birds
• Dog
• Rabbit
• Frog

Solution

Telescopic vision is found in birds, i.e. they have the ability to see distant objects clearly.

Q17. One of the examples of the action of the autonomous nervous system is

• Swallowing of food
• Pupillary reflex
• Peristalsis of the intestines
• Knee-jerk response

Solution

Peristalsis of the intestines is an example of the autonomous nervous system as it is an involuntary activity of the body and is not according to the will of an organism.

Q18. _______________ connects the cavity of the middle ear to the throat

• Auditory canal
• Semicircular canal
• Ampulla
• Eustachian tube

Solution

Eustachian tube connects the cavity of the middle ear to the throat

Q19. Eye lens focuses light on the retina containing rod cells which are photoreceptors. The number of rod cells in the eyes is

• 120 million
• 160 million
• 150 million
• 180 million

Solution

The total number of rod cells in the human retina has been estimated at 110-125 million.

Q20. One of the following examples of an action of the autonomic nervous system is  

• Knee jerk reflex  
• Pupillary reflex  
• Swallowing of food  
• Peristalsis of intestine  

Solution

Peristalsis of intestine is an example of an action of the autonomic nervous system (ANS). ANS controls the function of visceral organs.  

Q21. Iris is part of

• Sclerotic
• Choroid
• Choroid and retina
• Sclerotic and choroid

Solution

The iris consists of two layers—outer one in continuation with the choroid and inner one in continuation with the retina.

Q22. Mark the vitamin present in Rhodopsin

• Vitamin A
• Vitamin B
• Vitamin C
• Vitamin D

Solution

Rhodopsin, a visual purple pigment, is a derivative of vitamin A.

Q23. Nodes of Ranvier are found in  

• Non-myelinated nerve fibres  
• Myelinated nerve fibres  
• Both 1 and 2 above  
• None of the above  

Solution

Nodes of Ranvier are found in myelinated nerve fibres. These are the gaps between two adjacent myelin sheaths.  

Q24. The decoding and interpretation of visual information are carried by the  

• Cerebellum  
• Frontal lobe  
• Parietal lobe  
• Temporal lobe  
• Occipital lobe  

Solution

The cerebral hemisphere is divided into four lobes - anterior frontal lobe, middle parietal lobe, posterior occipital lobe and lateral temporal lobe.     The decoding and interpretation of visual information, shape and colour are carried by the occipital lobe.  

Q25. In human brain, the corpus callosum connects  

• Two optic lobes  
• Bone and muscle  
• Two cerebral hemispheres  
• Two lobes of the pituitary gland  

Solution

Two cerebral hemispheres are interconnected by a thick band of transverse nerve fibres called the corpus callosum.  

Q26. Adaptation of colour vision is found in

• Mammals
• Aves
• Reptiles
• All of the above

Solution

Adaptation of colour vision is the ability of some animals to detect colours. Animals belonging to Mammalia, Aves and Reptilia have strong colour vision.

Q27. The sensitive pigmented layer of the eye is

• Cornea
• Retina
• Sclerotic
• Iris

Solution

The retina consists of a pigmented layer and a nervous tissue layer.

Q28. The satiety centre of the brain is present in the  

• Cerebral hemisphere  
• Hypothalamus  
• Cerebellum  
• Medulla oblongata  

Solution

The centre of satiety, i.e. the feeling of being satisfied, is present in the hypothalamus of the brain.  

Q29. Colour perception in man is due to  

• Rhodopsin pigment in rod cells  
• Iodopsin pigment in cone cells  
• Iodopsin pigment in rod cells  
• Rhodopsin pigment in cone cells  

Solution

Colour perception in man is due to iodopsin pigment in cone cells. In the retina, there are three types of cones which respond to red (erythropsin), green (chloropsin) and blue light (cyanopsin). Other colours are detected by simultaneous stimulation of more than one type of cone cell.  

Q30. The reflex arc consists of

• Motor nerve
• Sensory nerve
• Both of the above
• None of the above

Solution

The reflex arc consists of both sensory nerve and motor nerve. The sensory nerve conducts the sensory impulse from the receptor organ to the spinal cord. The motor nerve conducts the motor nerve impulse from the spinal cord to the effectors.

Q31. The receptor absent in the tongue is  

• Thermoreceptor  
• Gustatoreceptor  
• Photoreceptor  
• None of the above  

Solution

Thermoreceptors (for temperature) and gustatoreceptors (for taste) are present in the tongue. Photoreceptors (for light) are present in the eye but absent in the tongue.  

Q32. Retina is most sensitive at

• Optic disc
• Periphery
• Macula lutea
• Fovea centralis

Solution

Macula lutea is a small area on the retina which lies opposite to the optical axis of the lens. It has a depression (the fovea centralis) in the middle. It is the area of most distinct day vision.

Q33. Nissl's granules are absent in the  

• Axon  
• Cyton  
• Dendron  
• Schwann cells  

Solution

The cyton and dendrites contain Nissl's granules. The axon does not have Nissl's granules. In myelinated nerve fibres, Schwann cells form a myelin sheath around the axon.  

Q34. The thermoregulatory centre in the body of a homeothermal animal and man is found in the

• Hypothalamus
• Cerebellum
• Cerebrum
• Medulla oblongata

Solution

The thermoregulatory centre is found in the hypothalamus of a homeothermal animal and man. It maintains homeostasis, i.e. it regulates the temperature of the body.

Q35. Nissl’s granules are present in

• RBC
• WBC
• Both 1 and 2 above
• Nerve cells

Solution

Nissl’s granules are present in the cytoplasm of the cell body and the dendrites of the neuron.

Q36. The normal hearing range for humans is ____________ Hz.

• 10 , 000 to 15,000 Hz
• 100 to 150 Hz
• 20 to 20,000 Hz
• 200 to 250 Hz

Solution

The normal hearing range for humans is 20 to 20,000 Hz.

Q37. Acute vision is present in

• Vulture
• Shark
• Bat
• Frog

Solution

Acute vision is found in birds like vulture.

Q38. The primitive nervous system is formed in  

• Sponge  
• Cnidaria  
• Echinodermata  
• Annelida  

Solution

The primitive nervous system is formed in Cnidaria and consists of nerve cells and fibres throughout the body.  

Q39. Pons, cerebellum and medulla together constitute

• Hindbrain
• Midbrain
• Forebrain
• Telencephalon
• Cerebral hemispheres

Solution

The hindbrain consists of three parts - cerebellum, medulla oblongata and pons.

Q40. Which one of the following does not act as a neurotransmitter?  

• Cortisone  
• Acetylcholine  
• Epinephrine  
• Norepinephrine