Endocrine System and Pituitary Gland Practice Flashcards

These vocabulary flashcards cover the anatomy, hormones, and physiological functions of the hypothalamus, pituitary gland, thyroid, and adrenal glands based on the lecture notes.

Adenohypophysis

The anterior pituitary gland, composed of glandular epithelium, which produces and secretes hormones such as GH, ACTH, TSH, PRL, FSH, and LH.

Neurohypophysis

The posterior pituitary gland, consisting of neural tissue, which secretes hormones (ADH and OT) that are produced by the hypothalamus.

Supraoptic nucleus

The specific hypothalamic nucleus responsible for producing Antidiuretic Hormone (ADH).

Paraventricular nucleus

The specific hypothalamic nucleus responsible for producing Oxytocin (OT).

Antidiuretic Hormone (ADH)

Also known as Vasopressin; it stimulates the reabsorption of $H_2O$ by kidneys to conserve water and causes the contraction of smooth muscle in arteries to increase blood pressure.

Oxytocin (OT)

A hormone that stimulates uterine contractions and the milk let-down reflex (milk ejection); it operates through a positive feedback loop.

Hypothalamic-hypophyseal portal system

A system consisting of a hypothalamic capillary bed, portal veins, and an anterior pituitary capillary bed that allows hypothalamic hormones to regulate the anterior pituitary.

Somatotrophs

Cells in the adenohypophysis that secrete Growth Hormone (GH).

Growth Hormone (GH)

Also called somatotropin; it promotes fat breakdown and gluconeogenesis in the short term, and stimulates the release of insulin-like growth factor (IGF) for long-term bone and muscle growth.

Prolactin (PRL)

A hormone that targets mammary glands to promote breast development and stimulate milk production/secretion; it is inhibited by dopamine (prolactin-inhibiting factor).

Thyroid Stimulating Hormone (TSH)

A hormone triggered by hypothalamic TRH that stimulates the growth of the thyroid gland and the synthesis/release of $T_3$ and $T_4$.

Adrenocorticotropic Hormone (ACTH)

A hormone released by hypothalamic CRH that stimulates the adrenal cortex to produce and secrete its hormones.

Follicle Stimulating Hormone (FSH)

A gonadotropin that stimulates primary follicle maturation and estrogen release in females, and spermatogenesis in males.

Luteinizing Hormone (LH)

A hormone that stimulates ovulation and the production of progesterone/estrogen in females, and stimulates interstitial cells in the testes to secrete testosterone in males.

Parafollicular cells

Also known as C cells of the thyroid gland, they produce calcitonin to increase bone formation and decrease blood calcium levels.

Thyroglobulin

A large thyroid hormone precursor protein secreted by follicle cells into the colloid where it attaches to iodine atoms.

Triiodothyronine ($T_3$)

A thyroid hormone formed by combining one monoiodothyronine (MIT) and one diiodothyronine (DIT).

Thyroxine ($T_4$)

A thyroid hormone formed by combining two diiodothyronine (DIT) molecules; it acts as a longer-lasting reservoir that can be converted to $T_3$ by target tissues.

Zona glomerulosa

The outer layer of the adrenal cortex composed of densely packed cells that produce mineralocorticoids like aldosterone.

Zona fasciculata

The middle layer of the adrenal cortex where cells are stacked in columns to secrete glucocorticoids (e.g., cortisol) and androgenic steroids.

Zona reticularis

The inner layer of the adrenal cortex arranged in loose clusters that secretes glucocorticoids and androgenic steroids.

Aldosterone

A mineralocorticoid controlled by the RAAS that maintains blood pressure by retaining sodium ($Na^+$) and water while excreting potassium ($K^+$) and hydrogen ions ($H^+$).

Cortisol

A glucocorticoid that increases protein breakdown, stimulates gluconeogenesis in the liver, increases lipolysis, and provides anti-inflammatory effects.

Graves' disease

A common cause of hyperthyroidism characterized by an over-production of thyroid hormone, goiter, and exophthalmos (bulging eyes).

Cushing's syndrome

A disorder resulting from cortisol over-secretion, characterized by a moon face, buffalo hump, truncal obesity, and muscle wasting.

Addison's disease

A condition caused by adrenal atrophy (often autoimmune or infectious) leading to hypopigmentation, hypotension, and cardiac insufficiency.

Pineal gland

An endocrine organ that secretes melatonin to regulate the biological clock and the sleep-wake cycle.

Renin-angiotensin-aldosterone system (RAAS)

The primary regulatory system for the secretion of aldosterone to maintain electrolyte balance and blood pressure.