Question

How is constriction of superior mesenteric artery sympathetic? Please EXPLAIN

How is the stimulation of sebaceous gland sympathetic? please EXPLAIN

Answer 1

Sympathetic response also known as Fright and Flight response will cause a number of changes in the body to adapt us to the situation.

In the case of Superior Mesenteric Artery, it has more of alpha 1 receptors which will cause vasoconstriction. Sympathetic nervous system stimulation causes vasoconstriction of most blood vessels, including many of those in the skin, the digestive tract, and the kidneys. This occurs as a result of activation of alpha-1 adrenergic receptors by norepinephrine released by post-ganglionic sympathetic neurons. These receptors exist throughout the vasculature of the body but are inhibited and counterbalanced by beta-2 adrenergic receptors (stimulated by epinephrine release from the adrenal glands) in the skeletal muscles, the heart, the lungs, and the brain during a sympathoadrenal response. The net effect of this is a shunting of blood away from the organs not necessary to the immediate survival of the organism and an increase in blood flow to those organs involved in intense physical activity.

Sebaceous gland is stimulated to during this flight or fright response by sympathetic stimulation just like any Emotional sweating is stimulated by stress, anxiety, fear, and pain; it is independent of ambient temperature. Acetylcholine acts on the eccrine glands and adrenaline acts on both eccrine and apocrine glands to produce sweat. Emotional sweating can occur anywhere, though it is most evident on the palms, soles of the feet, and axillary regions. Sweating on the palms and soles is thought to have evolved as a fleeing reaction in mammals: it increases friction and prevents slipping when running or climbing in stressful situations.

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