The Adrenal Gland and Hormones Quiz

Aldosterone production is regulated by sodium and water levels, angiotensin II (ang II), and potassium levels in the blood.

A hormone that stimulates aldosterone production.

Renal Outer Medullary Potassium channel, plays a role in potassium secretion in the kidneys.

Epithelial Sodium Channel, helps regulate sodium reabsorption in the kidneys.

Inner part of the adrenal gland, produces catecholamines.

Cortisol inhibits neuronal differentiation in chromaffin cells and promotes epinephrine production from norepinephrine.

Develops from mesodermal cells and produces steroid hormones.

Cells in the adrenal medulla that produce catecholamines.

Aldosterone regulates extracellular volume (ECV) by increasing sodium retention/absorption in the kidneys. This means it helps maintain the balance of fluids and electrolytes in the body.

Aldosterone acts on the kidneys to increase sodium and water reabsorption while promoting potassium secretion. It has similar effects in the colon, salivary glands, and sweat glands.

Angiotensin II (Ang II), extracellular potassium levels ([K+]), and ACTH stimulate aldosterone production. These factors increase the activity of enzymes involved in aldosterone synthesis.

Aldosterone is synthesized exclusively in the zona glomerulosa of the adrenal cortex. Only these cells contain aldosterone synthase, the enzyme needed for its production.

The renin-angiotensin system (RAS) and aldosterone work together to regulate blood pressure and fluid balance. Angiotensin II, a key player in the RAS, stimulates aldosterone production.

The adrenal medulla bridges the endocrine and sympathetic nervous systems, secreting catecholamines (like epinephrine and norepinephrine) into the blood.

Catecholamines are stored in chromaffin granules along with ATP, calcium, and chromogranins.

70-80% of adrenal medulla cells secrete epinephrine, the remaining 20-30% secrete norepinephrine, although circulating norepinephrine also comes from sympathetic nerves.

Circulating epinephrine is entirely derived from the adrenal medulla.

Only about 30% of circulating norepinephrine comes from the adrenal medulla, the rest comes from postganglionic sympathetic nerves.

Catecholamine secretion is mainly controlled by descending sympathetic signals, activated by types of stress (like exercise, low blood sugar, and surgery).

Hypothalamus and brainstem control sympathetic responses, receive inputs from different areas of the brain such as cerebral cortex, limbic system.

VMATs transport catecholamines back into the chromaffin granules.

There's a synergy between the stress response (CRH/ACTH/cortisol) and sympathetic epinephrine axis.

Stress is a key regulator of epinephrine and norepinephrine release.

A single catecholamine can trigger multiple different responses in the body, depending on its concentration and the receptors it binds to. For example, epinephrine can cause both vasodilation and vasoconstriction.

Acetylcholine (ACh) is the chemical signal that triggers catecholamine release from the adrenal medulla.

The body's rapid and coordinated response to stress involving the sympathetic nervous system and adrenal medulla. It activates the release of catecholamines, such as norepinephrine and epinephrine, to prepare the body for action. It involves various organs and systems.

Chromaffin cells in the adrenal medulla have nicotinic receptors that bind acetylcholine.

The adrenal medulla, directly controlled by the autonomic nervous system, responds very quickly to stress.

Sympathoadrenal responses can be triggered even before the actual stressor occurs. The nervous system anticipates the need for action.

Cortisol regulates epinephrine production by ensuring sufficient levels of norepinephrine.

Similar to the 'fight-or-flight' response, exercise triggers the release of catecholamines, particularly norepinephrine and epinephrine, to meet the increased energy demands of the body.

Catecholamines are degraded by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT).

Norepinephrine and epinephrine act on the heart to increase heart rate, strength of contractions, and constrict veins and lymphatics, all to increase blood flow to the muscles.

Catecholamines act through adrenergic G protein-coupled receptors (GPCRs).

α1 adrenergic receptors increase IP3 and DAG levels, leading to various effects like vasoconstriction.

Epinephrine promotes glycogenolysis in muscles to provide energy. It also increases blood glucose by promoting glycogenolysis and gluconeogenesis in the liver.

The sympathoadrenal response generally decreases the activity of smooth muscles in the digestive and urinary systems, conserving energy for essential functions.

α2 adrenergic receptors decrease cAMP levels, leading to effects like decreased insulin secretion.

β1 adrenergic receptors increase cAMP levels, leading to effects like increased heart rate.

A rare tumor caused by excessive growth of chromaffin cells in the adrenal medulla or other locations. These tumors release large amounts of catecholamines, leading to a variety of symptoms.

β2 adrenergic receptors increase cAMP levels, leading to effects like bronchodilation.

β3 adrenergic receptors increase cAMP levels, primarily in adipose tissue.