Endocrine System Fundamentals

Comprehensive vocabulary flashcards covering the major and accessory endocrine glands, their hormones, functions, and associated medical disorders based on the lecture transcript.

Hormone

A chemical messenger secreted into the bloodstream that stimulates a response in another tissue or organ.

Target cells

Cells that possess specific receptors for hormones.

Endocrine glands

Ductless organs that produce and secrete hormones into tissue fluids and possess dense capillary networks.

Exocrine glands

Glands that use ducts to carry secretions to the body surface or organ cavities, primarily for extracellular effects like food digestion.

Adenohypophysis

The anterior portion of the pituitary gland which secretes hormones such as GH, PRL, TSH, ACTH, FSH, and LH.

Neurohypophysis

The posterior portion of the pituitary gland which secretes ADH and OT.

Neuroendocrine cells

Neurons that secrete hormones into the extracellular fluid ($ECF$).

Steroid hormone

A hormone synthesized from a cholesterol backbone (lipid) that passes easily through the cell membrane, such as estrogen or testosterone.

Nonsteroid hormone

Hormones that are not lipid-based, including building blocks of proteins (amino acids like insulin) or groups of amino acids held by peptide bonds (peptides like oxytocin).

Trophic hormones

A functional classification of hormones that stimulate growth or secretion in other endocrine glands.

Anabolic hormones

Hormones that stimulate anabolism to build larger molecules.

Hypersecretion

The production of too much hormone by a diseased gland.

Hyposecretion

The production of too little hormone by a gland or a failure of the target cell to pick up the hormone.

Growth hormone (GH)

A hormone from the adenohypophysis that promotes bodily growth by stimulating protein anabolism, lipid catabolism, and affecting blood glucose levels.

Gigantism

A condition caused by the hypersecretion of Growth hormone ($GH$) in juveniles, affecting the long bones.

Pituitary dwarfism

A condition caused by the hyposecretion of Growth hormone ($GH$) in juveniles.

Prolactin (PRL)

Hormone that initiates lactation; hypersecretion can cause lactation in non-nursing women or impotence in men.

Thyroid stimulating hormone (TSH)

Promotes and maintains the growth and development of the thyroid gland and stimulates its secretion.

Adrenocorticotrophic hormone (ACTH)

Promotes and maintains the development of the adrenal cortex and stimulates it to secrete its hormones.

Follicle-stimulating hormone (FSH)

In females, it stimulates ovarian cells; in males, it stimulates development of seminiferous tubules and maintains sperm production.

Lutenizing hormone (LH)

In females, it stimulates the corpus luteum for estrogen and progesterone production; in males, it stimulates interstitial cells for testosterone production.

Antidiuretic hormone (ADH)

A neurohypophysis hormone that prevents the formation of large volumes of urine to maintain water balance.

Diabetes insipidus

A disorder resulting from the hyposecretion of $ADH$ characterized by the production of abnormally large amounts of urine.

Oxytocin (OT)

Stimulates uterine contractions via positive feedback, promotes milk let-down, and is associated with "coupling behavior" or as the "cuddle chemical."

Melatonin

A hormone secreted by the pineal gland at night to induce sleep and regulate circadian rhythms.

Seasonal affective disorder (SAD)

Severe depression during winter when day length is shorter, linked to the pineal gland.

Thyroid hormones (TH)

Molecules identified as $T_3$ and $T_4$ that work to increase the rate of metabolism.

Graves disease

A form of hyperthyroidism or toxic goiter causing unexplained weight loss, nervousness, increased heart rate, and exophthalmos (protrusion of eyeballs).

Simple goiter

Enlargement of the thyroid due to an iodine deficient disorder ($IDD$) in the diet.

Calcitonin (CT)

An antagonistic hormone to $PTH$ that increases $Ca^{+2}$ storage in the bone to lower blood plasma calcium levels.

Parathyroid hormone (PTH)

Increases the release of calcium ions from bone to increase $Ca^{+2}$ blood plasma levels; hyperparathyroidism can lead to bone softening and kidney stones.

Aldosterone

A mineralocorticoid that increases $Na^+$ reabsorption in the kidney to maintain homeostasis in blood plasma.

Addison’s disease

A condition caused by hyposecretion of cortisol and aldosterone, resulting in metallic bronzing of the skin and electrolyte imbalance.

Cortisol

A glucocorticoid (hydrocortisol) used for anti-inflammatory responses and influencing the metabolism of food.

Cushing syndrome

Hypersecretion of cortisol resulting in "moon face," "Buffalo hump," hyperglycemia, and high blood pressure.

Glucagon

Hormone produced by alpha cells in the pancreatic islets that increases blood glucose levels by converting glycogen to glucose.

Insulin

Hormone produced by beta cells in the pancreatic islets that decreases blood glucose by moving glucose out of the blood and into tissue.

Somatostatin

Produced by pancreatic delta cells; influences other pancreatic cells to produce hormones.

Type I diabetes mellitus

Insulin-dependent diabetes ($IDDM$) usually occurring in juveniles (age 12) due to autoimmune destruction of beta cells.

Type II diabetes mellitus

Non-insulin dependent diabetes ($NIDDM$) characterized by insulin resistance, often associated with age (age 40), obesity, and heredity.

Human chorionic gonadotrophic (hCG)

Hormone secreted by the placenta to maintain the placenta and uterine lining during the first trimester of pregnancy.

Thymosin

Hormone secreted by the thymus that helps develop T cells for the immune system.

Atrial natriuretic hormone (ANH)

Hormone secreted by the heart that regulates blood pressure in response to the loss of sodium.

Acromegaly

A disorder in adults caused by the hypersecretion of Growth hormone ($GH$).

Myxedema

Hypothyroidism in adults causing a low $BMR$, sluggishness, sleepiness, weight gain, and tissue swelling.

Polyuria

One of the three signs of diabetes mellitus, referring to excessive urine output.