Chapter 18: The Endocrine System Vocabulary Flashcards

Endocrine system

A body communication system that uses hormones to control body functions over time.

Hormones

Chemical messengers released by endocrine cells or glands that travel through the blood to reach target cells or target organs.

Target cell

A cell that responds to a specific hormone because it possesses the correct receptor for that hormone.

Homeostasis

The state of keeping the internal conditions of the body relatively stable.

Negative feedback

The dominant control principle of the endocrine system in which a response reduces the original stimulus to prevent excessive hormone release.

Adrenal cortex

The outer layer of the adrenal gland derived from mesoderm that produces steroid hormones.

Adrenal medulla

The inner layer of the adrenal gland derived from neural crest tissue that produces catecholamines for a rapid fight-or-flight response.

Zona glomerulosa

The outermost zone of the adrenal cortex that produces mineralocorticoids, especially aldosterone.

Zona fasciculata

The middle zone of the adrenal cortex that produces glucocorticoids, especially cortisol.

Zona reticularis

The innermost zone of the adrenal cortex that produces adrenal androgens such as DHEA.

Aldosterone

A mineralocorticoid steroid hormone produced by the zona glomerulosa that increases sodium reabsorption and potassium secretion in the kidneys.

Renin-angiotensin-aldosterone system (RAAS)

A major regulatory pathway initiated by kidney renin release in response to low blood pressure, low blood volume, or reduced renal perfusion, leading to angiotensin II and aldosterone release.

Cortisol

The major glucocorticoid produced by the adrenal cortex that supports prolonged stress response, maintains blood glucose, promotes gluconeogenesis, and reduces inflammation.

HPA axis

The hypothalamic-pituitary-adrenal axis that controls cortisol release through sequential secretion of CRH, ACTH, and cortisol.

Chromaffin cells

Modified sympathetic postganglionic neurons in the adrenal medulla that secrete epinephrine and norepinephrine into the blood.

Alpha cells

Endocrine cells in the pancreatic islets that produce glucagon to raise blood glucose.

Beta cells

Endocrine cells in the pancreatic islets that produce insulin to lower blood glucose.

Delta cells

Endocrine cells in the pancreatic islets that produce somatostatin to inhibit insulin and glucagon secretion.