Question

Which of the following is not an effect of the sympathetic nervous system?

• A. Dilation of pupil
• B. Inhibition of peristalsis
• C. Elevation of blood pressure
• D. Stimulation for saliva secretion

Answer 1

Answer: (D)

The sympathetic division typically functions in actions requiring quick responses. It promotes a "fight or flight" response, corresponds with arousal and energy generation and inhibits digestion. Few more functions are:
(i) Diverts blood flow away from the gastro-intestinal (GI) tract and skin via vasoconstriction
(ii) Blood flow to skeletal muscles and the lungs is enhanced (by as much as $1200\%$ in the case of skeletal muscles).
(iii) Dilates bronchioles of the lung, which allows for greater aveolar oxygen exchange.
(iv) Increases heart rate and the contractility of cardiac cells (myocytes), thereby providing a mechanism for the enhanced blood flow to skeletal muscles.
(v) Dilates pupils and relaxes the ciliary muscle to the lens, allowing more light to enter the eye and far vision.
(vi) Provides vasodilation for the coronary vessels of the heart.
(vii) Constricts all the intestinal sphincters and the urinary sphincter.
(viii) Inhibits peristalsis.
(ix) Stimulates organs.