Question

1. The sciatic nerve

​a. is the largest nerve in the body

​b. is a peripheral nerve

​c. is a spinal nerve

​d. a and b

​e. all of the above

2. The inner ear is the

​a. labyrinth

​b. cochlea

​c. tympanic cavity

​d. pinna

​e. endolymph

3. The right and left cerebral hemispheres are connected by the

​a. corpus callosum

​b. median aperture

​c. medial mass

​d. gray commissure

​e. nothing; they are separate structures

4. The master controller of the endocrine system is the

​a. pituitary gland

​b. thyroid gland

​c. hypothalamus

​d. thalamus

​e. pancreas

5. Preganglionic sympathetic axons run from the T1_L2 spinal nerves to the sympathetic trunk via

​a. white rami communicans

​b. grey rami communicans

​c. superior cervical ganglia

​d. splanchnic nerves

​e. celiac ganglion

6. The inner ear includes the

​a. auricle and external acoustic meatus

​b. stapes, incus, and malleus

​c. cochlea, and is within the petrous part of temporal bone

​d. tympanic membrane

​e. Eustachion tube

7. The ascending tract of the spinal cord that is the primary conveyor of sensory information after burning a hand is

​a. fasciculus gracilis

​b. corticobulbar tract

​c. lateral spinothalamic tract

​d. pyramidal tract

​e. posterior spinocerebellar tract

8. Venous blood from the heart wall enters the right atrium through the

​a. inferior vena cava

​b. superior vena cava

​c. pulmonary vein

​d. coronary sinus

​e. pulmonary artery

9. The region of the retina with the highest proportion of cones and almost no rods is the

​a. optic disc

​b. macula lutea

​c. fovea centralis

​d. amacrine cell layer

​e. pigment epithelium

10. Blood return to the heart is powered by

​a. massaging action of skeletal muscle in the general area of veins

​b. negative pressure in the thoracic cavity

​c. heart pumping

​d. a and b

​e. all of the above

​

11. The middle layer of the adrenal cortex that synthesizes glucocorticoids is the

​a. zona fasciculata

​b. zona reticularis

​c. zona glomerulosa

​d. zona corticosa

​e. zona medullaris

12. The inferior rectus muscle of the eye

​a. moves eyes laterally and is innervated by cranial nerve VI (abducens)

​b. moves eyes medially and is innervated by cranial nerve III (oculomotor)

​c. depresses eye and is innervated by cranial nerve III (oculomotor)

​d. elevates eye and is innervated by cranial nerve III (oculomotor)

​e. rotates eye and is innervated by cranial nerve VI (abducens)

13. In all cases

​a. arteries carry blood away from the heart; veins carry blood towards the heart

​b. veins carry blood away from the heart; arteries carry blood towards the heart

​c. arteries carry oxygenated blood; veins carry deoxygenated blood

​d. arteries carry deoxygenated blood; veins carry oxygenated blood

​e. no such generalization can be made for all cases

14. The valve between the right ventricle and the pulmonary trunk is the

​a. pulmonary semilunar valve

​b. bicuspid valve

​c. left atrioventricular valve

​d. mitral valve

​e. aortic semilunar valve

15. When blood glucose levels are elevated, insulin is secreted by (be as specific as possible)

​a. pancreatic acini

​b. pancreatic islets

​c. alpha cells

​d. beta cells

​e. delta cells

Answer 1

Question 1.

The sciatic nerve is :

a) is the largest nerve in the body

b) is a peripheral nerve

c) is a spinal nerve

d) both a) and b)

e) all of the above.

Answer: e) all of the above.

Explanation: Sciatic nerve is the longest and largest peripheral nerve in the body. It is a spinal nerve which originates from the lumbosacral plexus from the spinal nerve segments L4, L5, S1, S2, S3. It supplies the muscles of the hip, thigh and leg and foot region. Due to compression of the sciatic nerve, there is pain extending from the lower lumbar region to the leg known as sciatica.

Question 2.

The inner ear is :

Answer: a) labyrinth.

Explanation: The inner ear is also known as the labyrinth. It has two parts bony labyrinth and membranous labyrinth. Bony labyrinth is a hollow cavity in the temporal bone of the skull. Membranous labyrinth is fluid filled space inside the bony labyrinth. Inner ear is concerned with the function of hearing and maintaining equilibrium of the body.

Cochlea is a cavity inside the bony labyrinth which has special receptors called organ of corti which converts sound impulses into electrical signals. Thus, cochlea is concerned with the hearing function of inner ear.

Tympanic cavity is the cavity of the middle ear which has got ear ossicles like malleus, incus and stapes. These ear ossicles helps in transmission of sound. Tympanic cavity is seperated from the external ear by tympanic membrane (ear drum).

Pinna is the outer visible part of the ear made up of cartilage. It is also known as the auricle. It helps in collection of sound waves from the environment and directing it into the auditory cavity.

Endolymph is the potassium rich fluid inside the membranous labyrinth. The movement of the fluid inside the endolymph stimulates the receptors and helps in the functions of hearing and maintaining equilibrium.

Question 3.

The right and left cerebral hemispheres are connected by :

Answer: a) corpus callosum.

Explanation: Corpus callosum is a bundle of nerve axons that connects the two cerebral hemispheres. It's function is to establish a communication between the two similar regions of the cerebral hemispheres along with integrating the sensory and motor functions between the two cerebral hemispheres.

Median aperture is an opening in the brain which connects the fourth ventricle of the brain to the subarachnoid space. It is filled with cerebrospinal fluid (CSF) and helps in the constant circulation of the CSF.

Gray commissure is a comparatively thinner gray part of the spinal cord surrounding the central canal. It contains cell bodies of the neurons and hence appear gray.

Question 4.

The master controller of the endocrine system is the :

Answer: c) hypothalamus.

Explanation: The hypothalamus is a small structure made up of nervous tissue (mainly nuclei) located below the thalamus part of the brain. It acts as a connecting link between the endocrine system and the autonomic nervous system of the body by controlling the main endocrine gland, the pituitary gland. It controls the pituitary gland by secreting various releasing and inhibiting hormones that control the secretion of different hormones from the pituitary gland. Hence, hypothalamus is called the master controller of the endocrine system.

Pituitary gland is the main endocrine gland of the body which controls the activities of other endocrine glands. It is under the control of the hypothalamus. It secretes hormones like growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, gonadotropic hormones, etc.

Thyroid gland is a butterfly shaped gland located in the neck region which secretes hormones like tri-iodothyronine(T3) and tetra-iodothyronine(T4) also known as thyroxine which controls the metabolic processes of the body.

Thalamus is a mass of gray mater located in the posterior aspect of the forebrain above the hypothalamus. It acts as the relay center for the sensory nerve signals from the spinal cord to the cerebrum as well as motor signals from the cerebral cortex.

Pancreas is an organ situated behind the stomach and acts as both endocrine and exocrine gland. It's endocrine function is by secretion of hormones like insulin and glucagon directly into the blood stream to regulate the levels of blood glucose. It's exocrine function is by secretion of digestive enzymes into the duodenum through pancreatic duct which helps in breakdown and digestion of all three macronutrients i.e. proteins, carbohydrates and fats.