2nd Year MBBS Unit-5 Internal Assessment, May 2000 Paper - III B (CNS) SHORT ANSWER QUESTIONS

(B-98)                                                                                              

 8th May 2000

B.P. KOIRALA INSTITUTE OF HEALTH SCIENCES, DHARAN, NEPAL

2nd Year MBBS Unit-5

Internal Assessment, May 2000

Paper - III B

(CNS)

SHORT ANSWER QUESTIONS

Time: 2 hours                                                                                       

                    Maximum Marks: 125

Please answer each section in a separate answer book.

Anatomy
SECTION 'A'


1.    Describe the formation of arterial circle at the base of human brain.                       
   5
2.   a.    State the extent and subdivisions of the spinal nucleus of the trigeminal nerve.     2
b.    Which sensory modalities are sub-served by each of these subdivisions.               1.5
c.    Describe the afferent and efferent connections responsible for the corneal reflex. 1.5
3.    a.    Describe how the thalamic nuclei are classified.                                       
            2
b.    What is the ventral posterior nucleus of the thalamus concerned with?                 1
c.    Enumerate four major afferents to this nucleus.                                             
       2
4.   Enumerate the afferent and efferent tracts passing through superior cerebellar  peduncle.     
                                                                                                   
               5
5.   Enumerate the peripheral parasympathetic ganglia of the head region and
mention the structures supplied by each one of them.                                               
    5
6.   Enumerate the functional components, nuclei, and branches of the
glossopharyngeal nerve.                                                                           
                    5
7.    Describe the lateral medullary syndrome of Wallenberg.                                       
      5
8.    Describe the formation and termination of the medial lemniscus of brain.                    5

Physiology
SECTION 'B'


9.    List three important functions of CSF. Explain the contrecoup phenomena.                3+1

10.  Describe briefly the sites and mechanisms of formation of CSF.                               
 4

11.  Compare the ionic basis of EPSP and IPSP.                                                     
            3


12. State the important functions of primary & secondary somatosensory cortex. 3

13.  Draw a diagram showing descending modulation of pain.                                         
   4

14.  State the functional differences between intrafusal & extrafusal muscle fibers.            3

15. Explain briefly with the help of a diagram the functional divisions of the
cerebellum.                                                                                       
                            4

16. State mechanisms underlying cortical arousal and explain how the system can
be activated by emotional stress.                                                                 
                 3
17. Describe briefly characteristic features of slow wave sleep and name two neurotransmitters
associated with production of sleep.                                                  4
18.  Name two major reward centers and explain briefly their functional implication.        4
19.  Explain the terms: Memory trace and Habituation.                                             
         4

Pathology
SECTION 'C'


20.  What are “Prion Diseases”? Name four diseases that fall under this category.            3+2

21. Tabulate 2 important differences between brain infarction caused by thrombosis
and embolism.                                                                                     
                          2

22.  Classify neuroepithelial tumors of CNS.                                                       
                3

Pharmacology
SECTION 'D'


23.  Explain why:                                                                                 
                                2x5=10
a.    Naloxone is used in acute morphine over dosage.
b.   Diazepam is used as preanaesthetic medication before surgery.
c.    Anticholinergic drugs are used to treat neuroleptics induced extra pyramidal motor side
effect.
d.   Phenytoin can cause osteomalacia and megalobalstic anaemia after prolonged use.
e.    Lignocaine with adrenaline is not used for ring block anaesthecia in index finger.

24. Describe briefly the mechanism of action, common side effects and clinical
uses of the following drugs.                                                                       
                    5x2=10
a.    Carbamazepine
b.   Haloperidol

Psychiatry
SECTION 'E'


25.  Describe briefly the types of learning.                                                       
                   5
26. Describe briefly the biological basis of memory with reference to LTP
(Long Term Potentiation)                                                                           
                   5
27.  Describe briefly the concept of intelligence.                                                 
                5
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