The adrenal glands, located superior to each kidney, consist of two regions: the adrenal cortex and adrenal medulla. The adrenal cortex—the outer layer of the gland—produces mineralocorticoids, glucocorticoids, and androgens. The adrenal medulla at the core of the gland produces epinephrine and norepinephrine.
The adrenal glands mediate a short-term stress response and a long-term stress response. A perceived threat results in the secretion of epinephrine and norepinephrine from the adrenal medulla, which mediate the fight-or-flight response. The long-term stress response is mediated by the secretion of CRH from the hypothalamus, which triggers ACTH, which in turn stimulates the secretion of corticosteroids from the adrenal cortex. The mineralocorticoids, chiefly aldosterone, cause sodium and fluid retention, which increases blood volume and blood pressure.
adrenal cortex
outer region of the adrenal glands consisting of multiple layers of epithelial cells and capillary networks that produces mineralocorticoids and glucocorticoids
adrenal glands
endocrine glands located at the top of each kidney that are important for the regulation of the stress response, blood pressure and blood volume, water homeostasis, and electrolyte levels
adrenal medulla
inner layer of the adrenal glands that plays an important role in the stress response by producing epinephrine and norepinephrine
angiotensin-converting enzyme
the enzyme that converts angiotensin I to angiotensin II
alarm reaction
the short-term stress, or the fight-or-flight response, of stage one of the general adaptation syndrome mediated by the hormones epinephrine and norepinephrine
aldosterone
hormone produced and secreted by the adrenal cortex that stimulates sodium and fluid retention and increases blood volume and blood pressure
chromaffin
neuroendocrine cells of the adrenal medulla
cortisol
glucocorticoid important in gluconeogenesis, the catabolism of glycogen, and downregulation of the immune system
epinephrine
primary and most potent catecholamine hormone secreted by the adrenal medulla in response to short-term stress; also called adrenaline
general adaptation syndrome (GAS)
the human body’s three-stage response pattern to short- and long-term stress
glucocorticoids
hormones produced by the zona fasciculata of the adrenal cortex that influence glucose metabolism
mineralocorticoids
hormones produced by the zona glomerulosa cells of the adrenal cortex that influence fluid and electrolyte balance
norepinephrine
secondary catecholamine hormone secreted by the adrenal medulla in response to short-term stress; also called noradrenaline
stage of exhaustion
stage three of the general adaptation syndrome; the body’s long-term response to stress mediated by the hormones of the adrenal cortex
stage of resistance
stage two of the general adaptation syndrome; the body’s continued response to stress after stage one diminishes
zona fasciculata
intermediate region of the adrenal cortex that produce hormones called glucocorticoids
zona glomerulosa
most superficial region of the adrenal cortex, which produces the hormones collectively referred to as mineralocorticoids
zona reticularis
deepest region of the adrenal cortex, which produces the steroid sex hormones called androgens
Visit this link to view an animation describing the location and function of the adrenal glands. Which hormone produced by the adrenal glands is responsible for mobilization of energy stores?
Cortisol.
1. The adrenal glands are attached superiorly to which organ?
A) thyroid
B) liver
C) kidneys
D) hypothalamus
C
2. What secretory cell type is found in the adrenal medulla?
A) chromaffin cells
B) neuroglial cells
C) follicle cells
D) oxyphil cells
A
3. Cushing’s disease is a disorder caused by ________.
A) abnormally low levels of cortisol
B) abnormally high levels of cortisol
C) abnormally low levels of aldosterone
D) abnormally high levels of aldosterone
B
4. Which of the following responses is not part of the fight-or-flight response?
A) pupil dilation
B) increased oxygen supply to the lungs
C) suppressed digestion
D) reduced mental activity
D
1. What are the three regions of the adrenal cortex and what hormones do they produce?
The outer region is the zona glomerulosa, which produces mineralocorticoids such as aldosterone; the next region is the zona fasciculata, which produces glucocorticoids such as cortisol; the inner region is the zona reticularis, which produces androgens.
2. If innervation to the adrenal medulla were disrupted, what would be the physiological outcome?
Damage to the innervation of the adrenal medulla would prevent the adrenal glands from responding to the hypothalamus during the fight-or-flight response. Therefore, the response would be reduced.
3. Compare and contrast the short-term and long-term stress response.
The short-term stress response involves the hormones epinephrine and norepinephrine, which work to increase the oxygen supply to organs important for extreme muscular action such as the brain, lungs, and muscles. In the long-term stress response, the hormone cortisol is involved in catabolism of glycogen stores, proteins, and triglycerides, glucose and ketone synthesis, and downregulation of the immune system.