Central Nervous System (Physiology practice multiple choice questions for FCPS, MRCP, USMLE, and PLAB)

1) Lesions of which of the following nuclei cause hypothalamic obesity

a. ventromedial nucleus              

b. dorsomedial nucleus

c. suprachiasmatic nucleus          

d. supraoptic nucleus

Ans. a

2) The EPSP

a. is an all or none response to a presynaptic potential  

b. can be temporarily summated during repetitive presynaptic stimulation

c. always initiates an action potential     

d. lasts only for the duration of presynaptic action potential

Ans. b

3) Following statements are true for dopamine except

a. it is related to Parkinsonism   

b. it is found in the cells uninhibited by Ach in basal ganglia

c. it is one of the endogenous opiates from CNS               

d.  it cannot be replaced in CNS from dietary dopamine

Ans. c

4) Loss of fear and emotion is often observed in the lesion at

a. septal nucleus             

b. thalamus

c. amygdaloidal nucleus               

d. sensory cortex

Ans. c

5) The Renshaw cell

a. receive recurrent collaterals from motor neurons and inhibit other motor neurons in the vicinity         

b. is the inhibitory system of cerebellum

c. are a major component of muscle spindle       

d. are present in retina

Ans. a

6) Premotor cortex refers to

a. some areas anterior to primary motor cortex causing complex co-ordinate movements like speech, eye movements                

b. an area of motor cortex responsible  for voluntary movements

c. an area in temporal cortex     

d. an area of cerebellum

Ans. a

7) Functions of limbic system are all EXCEPT

a. olfaction         

b. gustation

c. feeding behaviour     

d. sexual behaviour

Ans. b

8) REM is

a. characterised by delta waves on ECG                

b. a sound and dreamless sleep

c. characterised by total lack of muscular activity              

d. referred to as paradoxical sleep

Ans. d

9) Sleep deprivation

a. can cause psychotic episodes               

b. is associated wit sluggishness of thoughts

c.  makes a person more alert   

d. has no effect on the individual

Ans. a

10) The sympathetic system

a. has short post ganglionic fibres            

b. consists of vagus nerve

c. produces nicotine at its nerve endings              

d. has a thoraco-lumbar outflow from the spinal cord

Ans. d

11) Visceral pain

a. shows relatively rapid adaptation       

b. is mediated by beta fibres in dorsal root of spinal nerves

c. can sometimes be relieved by applying irritant to skin               

d. can be produced by prolonged stimulation of touch receptors

Ans. c

12) The naked nerve endings are responsible for the sensation of

a. pain  

b. touch

c. hearing           

d. vision

Ans. a

13) When a normally innervated skeletal muscle is stretched the initial response is contraction, with increase in the stretch sudden relaxation occurs because of

a. decrease in gamma efferent discharge            

b. inhibition of the discharge from annulospiral endings of afferent nerve fibres

c. decreased activity of afferent nerve fibres from golgi tendon organs

d. increased activity of afferent nerve fibres from golgi tendon organs

Ans. d

14) After anterolateral cordotomy relief of pain is due to interruption of

a. left dorsal column      

b. left ventral spinothalamic tract

c. right lateral spinothalamic tract            

d. left lateral spinothalamic tract

Ans. d

15) Parasympathetic system

a. has short preganglionic fibres               

b. secretes dopamine

c. controls most of the movements and secretions of gut            

d. brings increase in heart rate during exercise

Ans. c

16) In a health adult sitting with eyes closed the EEG rhythm observed with electrodes on occipital lobes

a.  alpha              

b. theta

c. delta                

d. beta

Ans. a

17) The basal ganglia are primarily concerned with

a. sensory integration   

b. short term memory

c. control of movement

d. neuroendocrine control

Ans. c

18) Interruption of motor pathways in the internal capsule on one side causes

a. spastic paralysis on the same side       

b. spastic paralysis on the opposite side

c. flaccid paralysis on the same side        

d. flaccid paralysis on the opposite side

Ans.b

19) the extrapyramidal system is not concerned with

a. stretch reflex               

b. righting reflex

c. spasticity        

d. sensation of viscera

Ans. d

20) After falling down from a staircase a young woman is found to have partial loss of voluntary movement on the right side of the body and loss of pain and temperature sensation on the left side below the mid-thoracic region. The probable site of lesion is

a. transection of the right half of the spinal cord in the upper thoracic region      

b. transection of the left side of the spinal cord in the upper thoracic region

transection of sensory and motor pathways on the right side of the pons            

d. transection of the left half of the spinal cord in the lumbar region

Ans. a

21) Thirst is stimulated by

a. increase in plasma osmolality and volume       

b. increase in plasma osmolality and decrease in volume

c. decrease in osmolality and increase in volume              

d. decrease in plasma osmolality and volume

Ans. d

22)Lesions of which of the following hypothalamic nuclei cause loss of circadian rhythm

a. ventromedial               

b. dorsomedial

c. suprachiasmatic          

d. supraoptic

Ans.c

23) Normal blood flow to the brain is

a. greatly modified by vasomotor control             

b. about 150ml/min

c. about 750ml/min        

d. greatly increased during exercise

Ans.c

24) Retrograde amnesia

a. is abolished by prefrontal lobectomy                

b. responds to drugs that block dopamine receptors

c. is commonly precipitated by a blow on the head          

d. is commonly precipitated by ageing

Ans. c

25) Non fluent aphasia is produced by lesion of

a. Brocas area   

b. angular gyrus

c. parietal lobe

d. frontal lobe

Ans. b