Endocrine System Lecture Flashcards

Vocabulary flashcards covering topics from the pituitary, adrenal, pineal, and thymus glands, including hormone functions, gland anatomy, feedback loops, and clinical disorders.

Posterior Pituitary

A structure made of neural tissue that stores and releases hormones, specifically antidiuretic hormone (ADH) and oxytocin (OT), which are synthesized by hypothalamic neurons.

Antidiuretic Hormone (ADH)

Also called vasopressin; a posterior pituitary hormone that acts on the kidneys to reduce urine volume, promote water retention, and prevent dehydration.

Oxytocin (OT)

A posterior pituitary hormone that stimulates uterine contractions during childbirth and triggers the release of milk into the ducts of the mammary glands during lactation.

Growth Hormone (GH)

Also called somatotropin; an anterior pituitary hormone targeting tissues throughout the body to promote growth and tissue repair via the breakdown of proteins and fats.

Prolactin (PRL)

An anterior pituitary hormone targeting the mammary glands to stimulate milk secretion.

Thyroid-Stimulating Hormone (TSH)

An anterior pituitary hormone targeting the thyroid gland to stimulate thyroid gland growth and thyroid hormone secretion.

Adrenocorticotropic Hormone (ACTH)

An anterior pituitary hormone targeting the adrenal cortex to stimulate its growth and the secretion of corticosteroids.

Follicle-Stimulating Hormone (FSH)

An anterior pituitary hormone targeting the ovaries and testes; in females, it stimulates ovarian follicle growth and estrogen secretion, while in males, it stimulates sperm production.

Luteinizing Hormone (LH)

An anterior pituitary hormone targeting the ovaries and testes; in females, it stimulates ovulation and corpus luteum maintenance, while in males, it stimulates testosterone secretion.

Endocrinology

The study of the endocrine system and the diagnosis and treatment of its disorders.

Negative Feedback

A regulatory mechanism in the hypothalamic-pituitary axis where a hormone secreted by a target organ feeds back to inhibit the release of its tropic hormone by the pituitary or hypothalamus.

Adrenal Medulla

The inner portion of the adrenal gland consisting of modified neurons (chromaffin cells) that acts as part of the sympathetic nervous system by secreting catecholamines.

Chromaffin Cells

Modified neurons located in the adrenal medulla that secrete catecholamines (specifically epinephrine and norepinephrine) in response to sympathetic stimulation.

Glycogenolysis

The physiological process of breaking down glycogen into glucose to boost blood glucose levels.

Gluconeogenesis

The physiological process of converting fatty acids and amino acids into glucose to boost fuel availability.

Adrenal Cortex

The outer glandular portion of the adrenal gland that consists of three layers and secretes steroid hormones called corticosteroids.

Zona Glomerulosa

The outermost layer of the adrenal cortex that secretes mineralocorticoids, principally aldosterone.

Aldosterone

The principal mineralocorticoid secreted by the zona glomerulosa that acts on the kidneys to promote $Na^+$ retention, $K^+$ excretion, and indirect water retention.

Zona Fasciculata

The middle layer of the adrenal cortex that secretes glucocorticoids, principally cortisol.

Cortisol

The principal glucocorticoid secreted by the zona fasciculata that helps the body adapt to stress and repair tissue by breaking down fat/protein, converting them to glucose, and exerting anti-inflammatory effects.

Zona Reticularis

The innermost layer of the adrenal cortex that secretes sex steroids, including weak androgens and small amounts of estrogen.

Cushing Syndrome

A disorder resulting from the hypersecretion of cortisol, characterized by symptoms including a moon face, buffalo hump, hyperglycemia, muscle weakness, edema, loss of bone mass, and hypertension.

Addison's Disease

Also called adrenal cortical insufficiency; a life-threatening disorder caused by the hyposecretion of mineralocorticoids and glucocorticoids, marked by loss of fluid/electrolytes, weakness, muscle wasting, dehydration, and weight loss.

Hypothalamic-Pituitary-Adrenal (HPA) Axis

A neuroendocrine pathway stimulated during continued stress where the hypothalamus releases CRH, prompting the pituitary to release ACTH, which causes the adrenal cortex to secrete cortisol.

Corticotropin-Releasing Hormone (CRH)

A hypothalamic hormone released during stress that prompts the pituitary gland to secrete adrenocorticotropic hormone (ACTH).

Pineal Gland

A tiny, cone-shaped gland located on the roof of the brain's third ventricle that produces melatonin to regulate the sleep-wake cycle.

Melatonin

A hormone produced by the pineal gland that rises at night and falls during the day, triggering sleepiness as part of the sleep-wake cycle.

Seasonal Affective Disorder (SAD)

A mood disorder occurring in winter months when sunlight exposure is limited, linked to greater seasonal fluctuations in melatonin and characterized by sleepiness, low energy, irritability, and carbohydrate cravings.

Thymus

An organ located in the mediastinum beneath the sternum that secretes hormones for immune system development, which is large in children but shrinks starting at puberty to mostly fat and fibrous tissue in old age.

Thymosin and Thymopoietin

Two hormones secreted by the thymus gland that play a key role in the development of the immune system.