Question

When the sympathetic nervous system is activated, you would expect all of the following responses EXCEPT... Select one: O a. contraction of radial ocular muscle. (Contraction of this muscle would dilate the pupil.) b. vasodilation in skeletal muscle. c. insulin secretion. (Insulin is the hormone responsible for reducing blood glucose levels by moving glucose into cells for storage.) d. inhibition of intestinal peristalsis. (Peristalsis is the muscular movements that propel food through the digestive tract.)

Answer 1

c). Insulin secretion. ( insulin secretion is mainly caused by parasympathetic nervous system, which helps in digestion and lowers blood glucose levels).

Whereas pupilary dilatation, vasodilation of skeletal muscle and inhibition of peristalsis is done by sympathetic nervous system.  

Explanation: autonomic nervous system includes sympathetic and parasympathetic nervous system. In this parasympathetic is dominant during rest and digestion . Sympathetic is activated mainly in stressful situations.  

Sympathetic nervous system has noradrenaline as neurotransmitter which acts on specific receptors in various body systems and prepares our body to overcome stressful situations. Functions of sympathetic nervous system are :

• Dilation of pupil
• Increases heart rate
• Bronchodilation in lungs
• Decreases motility of gut and secretions of gut
• Causes vasodilation of skeletal muscle
• Inhibit insulin secretion and cause hepatic glycogenolysis and increase blood glucose level .
• Stimulates norepinephrine, epinephrine, cortisol secretion in adrenal glands .
• Micturition is inhibited by relaxation of bladder .

parasympathetic nervous system has acetylcholine as major neurotransmitter and acts on muscarnic and nicotinic receptors and has opposite function to sympathetic nervous system :

• constriction of pupil
• Decreases heart rate
• Bronchoconstriction of lungs
• Increases gut motility , helps in digestion .
• Decreases blood glucose level by insulin secretion.
• Cause muscle contraction by acting on nicotinic receptors
• Cause contraction of bladder , which cause urination.