One function of catecholamines released by the adrenal glands during times of stress is to:

Question

Quizplus · Accepted Answer

11ecba2d_1016_3c37_a3bf_ab78920f45fc_MD0008_00 The adrenal glands are divided into two subdivisions, the adrenal cortex and adrenal medulla. Hormones secreted by the adrenal medulla and cortex modulate function in a way that enables the body to respond to stressful situations. Specifically, adrenal hormones promote the "fight-or-flight" response. For example, in response to a stressor, the adrenal medulla releases catecholamines (norepinephrine and epinephrine) that induce the following physiological changes: Redirection of blood flow throughout the body via vasoconstriction and vasodilation Vasoconstriction (narrowing) of blood vessels and reduced blood supply to organs that carry out nonessential functions (eg, stomach, intestines, kidneys) conserve oxygen and nutrients for organs that are necessary for immediate survival. Vasodilation (widening) of blood vessels increases blood flow to organs essential for immediate survival (eg, heart, skeletal muscle). Increased heart rate and cardiac muscle contractility promote increased blood flow to the brain, lungs, and skeletal muscles, allowing an organism to process and execute a response to the stressful stimulus. Dilation of airways (bronchioles) enables increased respiratory function and oxygen delivery to tissues. (Choice A) Melatonin, a hormone that promotes drowsiness and sleep, is released by the pineal gland in response to low light levels (detected by the retina). Adrenal gland activity is not involved in the regulation of the pineal gland. (Choice C) Although glucose reabsorption occurs in the kidney, adrenal hormones (eg, aldosterone) do not affect this process. However, aldosterone does stimulate the reabsorption of sodium and water in the kidneys. (Choice D) By decreasing blood flow to the stomach and other digestive organs, the actions of hormones secreted by the adrenal gland will decrease digestive activity, likely inhibiting the secretion of the digestive enzymes that break down food. Educational objective: During the stress response, catecholamines secreted from the adrenal medulla act to promote the "fight-or-flight" response. Some effects of catecholamines include redirected blood flow to maximize the delivery of oxygen and other nutrients to organs essential for immediate survival (eg, brain, lungs, skeletal muscles), increased heart rate, and dilated airways.

One Function of Catecholamines Released by the Adrenal Glands During