132 VETERINARY STATE BOARD 



What are the functions of the spinal nerves? 



The superior roots convey sensory impulses from the whole 

 body, except certain parts of the face. The inferior roots convey 

 motor impulses to all of the voluntary muscles, also to the bladder, 

 uterus, intestines, other hollow viscera, blood-vessels, and sweat- 

 glands. 

 What would be the effect of division of one of the inferior nerve roots 

 of the spinal nerves? 

 Motor paralysis would follow in the parts supplied by the nerve. 



What would be the effect if both nerve roots of the spinal nerves were 

 cut? 

 Sensory and motor paralysis would follow in the parts supplied 

 by these branches. 



What is reflex action? Describe an experiment illustrating reflex 



action. 



Any involuntary action produced by a stimulus that is conveyed 



to the central nervous system and reflected to the periphery. If 



the foot of a frog, with its brain destroyed, is pinched, the leg will 



be drawn away from the irritant. 



Discuss the reflex functions of the spinal cord. 



In the spinal cord, there are a great number of reflex nerve cen- 

 tres which are capable of acting independently to a greater or 

 less extent. Each centre has an afferent and an efferent root and 

 is able to generate impulses which are carried to the periphery 

 without any assistance from the brain. This is shown by experi- 

 ments conducted on a frog with the brain destroyed as described in 

 the preceding answer. 



What is the difference in function between the superior and the inferior 

 columns of the spinal cord? 

 Through the superior column, impressions, such as temperature, 

 pressure and muscular sense, are conveyed to the cerebrum. The 

 inferior column conveys motor impulses to the body. The respira- 

 tory and vasomotor fibres also pass through the inferior column. 

 So it may be said that the superior column is an afferent channel 

 and the inferior column an efferent channel. 



What is the difference between a motor nerve and a sensory nerve? 



A motor nerve carries motor impulses from a centre to the 

 periphery (efferent). 



A sensory nerve carries impulses from the periphery to a centre 

 (afferent) . 



