Endocrine System Terminology, Anatomy, and Pathology

Vocabulary practice flashcards covering endocrine gland anatomy, physiological secretions, pathologic hypersecretion/hyposecretion conditions, diagnostic tests, and clinical abbreviations.

Endocrine Glands

Glands that secrete hormones directly into the bloodstream without ducts.

Exocrine Glands

Glands that send chemical substances via ducts to target areas.

Receptors

Recognition sites located in various target tissues upon which hormones act.

Prostaglandins

Chemical secretions produced by body cells that stimulate aggregation of platelets, contract the uterus, lower acid secretion in the stomach, and lower blood pressure.

Cholecystokinin

Hormone secreted by the gastrointestinal tract that contracts the gallbladder.

Erythropoietin

Hormone secreted by the kidneys that stimulates erythrocyte (red blood cell) production.

Melatonin

Hormone secreted by the pineal gland that induces sleep and affects mood.

Human Chorionic Gonadotropin (hCG)

Hormone secreted by the placenta that sustains pregnancy.

Isthmus

The central anatomical strip of tissue that connects the two lateral lobes of the thyroid gland draped over the trachea.

Thyroxine ($T_4$)

Hormone synthesized from iodine by the thyroid gland (also called tetraiodothyronine) that aids cells in oxygen uptake and increases metabolic rate.

Triiodothyronine ($T_3$)

Hormone synthesized from iodine by the thyroid gland that stimulates oxygen consumption and increases cellular metabolism.

Calcitonin

Thyroid hormone that stimulates calcium to leave the blood and enter the bone, decreasing blood calcium levels.

Parathyroid Hormone (PTH)

Hormone secreted by the parathyroid glands that mobilizes calcium from bones into the bloodstream to increase blood calcium.

Glucocorticoids

Adrenal cortex corticosteroids, including cortisol, that influence the metabolism of sugars, fats, and proteins, exert anti-inflammatory actions, and raise blood glucose in response to stress.

Aldosterone

Mineralocorticoid hormone secreted by the adrenal cortex that regulates sodium reabsorption and potassium excretion by the kidneys, regulating blood volume and blood pressure.

Epinephrine

Catecholamine secreted by the adrenal medulla (also known as adrenaline) that increases heart rate and blood pressure, dilates bronchial tubes, and releases glucose from storage.

Norepinephrine

Catecholamine secreted by the adrenal medulla (also known as noradrenaline) that constricts blood vessels to raise blood pressure.

Sympathomimetic Agents

Substances (such as epinephrine and norepinephrine) that mimic the physiological actions of the sympathetic nervous system.

Islets of Langerhans

Specialized endocrine tissue clusters in the pancreas containing alpha, beta, and delta cells that secrete hormones directly into the circulation.

Insulin

Hormone produced by pancreatic beta cells that facilitates the transport of glucose into cells, promotes glycogen synthesis, and lowers blood sugar.

Glucagon

Hormone produced by pancreatic alpha cells that raises blood sugar by breaking down glycogen stored in liver cells into glucose.

Adenohypophysis

The anterior lobe of the pituitary gland, composed of glandular tissue, which secretes hormones under the influence of hypothalamic releasing and inhibiting factors.

Neurohypophysis

The posterior lobe of the pituitary gland, composed of nervous tissue, which stores and releases hormones synthesized in the hypothalamus.

Growth Hormone (GH)

Anterior pituitary hormone (also known as somatotropin or STH) that regulates the development and growth of bones, muscles, and body tissues.

Adrenocorticotropic Hormone (ACTH)

Hormone secreted by the anterior pituitary gland that stimulates the growth of the adrenal cortex and increases the secretion of corticosteroids, primarily cortisol.

Antidiuretic Hormone (ADH)

Hormone synthesized in the hypothalamus and stored/released by the posterior pituitary (also termed vasopressin) that stimulates water reabsorption by kidney tubules and increases blood pressure by constricting arterioles.

Oxytocin (OT)

Posterior pituitary hormone that stimulates uterine contractions during childbirth, maintains labor, and causes milk ejection from mammary glands during suckling.

Goiter

Enlargement of the thyroid gland, which can occur as an endemic goiter due to iodine deficiency or as a nodular/adenomatous goiter with nodules and adenomas.

Graves Disease

Autoimmune condition of hyperthyroidism characterized by increased metabolism, hyperactivity, weight loss, nervousness, and exophthalmos.

Myxedema

Advanced hypothyroidism occurring in adulthood characterized by dry, puffy skin, sluggishness, and potential atherosclerosis resulting from increased blood lipid levels.

Cretinism

Congenital condition caused by severe hypothyroidism during infancy, resulting in impaired physical and mental development.

Tetany

State of persistent muscle spasms caused by hypocalcemia, commonly secondary to hypoparathyroidism.

Adrenal Virilism

Condition caused by hypersecretion of adrenal androgens by the adrenal cortex, producing symptoms such as amenorrhea, hirsutism, acne, and voice deepening in females.

Cushing Syndrome

Cluster of clinical abnormalities caused by excess cortisol secretion from the adrenal cortex, presenting with obesity, moon face, buffalo hump, and thoracic fat deposition.

Addison Disease

Hypofunctioning of the adrenal cortex with deficient production of mineralocorticoids and glucocorticoids, resulting in fatigue, muscle atrophy, weakness, low blood pressure, severe fluid loss, and hyperpigmentation.

Pheochromocytoma

Benign tumor of the adrenal medulla causing hypersecretion of epinephrine and norepinephrine, leading to hypertension, heart palpitations, severe headaches, and sweating.

Type 1 Diabetes Mellitus

Autoimmune disease characterized by complete insulin deficiency, abrupt onset usually before age $30$, thin or normal body weight, and frequent development of ketoacidosis.

Type 2 Diabetes Mellitus

Metabolic disorder characterized by insulin resistance and gradual onset usually after age $30$, highly associated with obesity in $85\%$ of affected individuals.

Acromegaly

Hypersecretion of growth hormone by the anterior pituitary gland occurring after puberty, leading to pathological enlargement of extremities and facial bones.

Gigantism

Hypersecretion of growth hormone by the anterior pituitary gland occurring before puberty, resulting in abnormal generalized overgrowth of body tissues.

Pituitary Dwarfism

Congenital hyposecretion of growth hormone from the anterior pituitary gland resulting in proportionate short stature.

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

Excessive secretion of antidiuretic hormone by the posterior pituitary resulting in abnormal body water retention.

Diabetes Insipidus (DI)

Insufficient secretion of antidiuretic hormone by the posterior pituitary gland, producing dilute urine, polyuria, and polydipsia.

Exophthalmometry

Clinical procedure measuring the forward protrusion of the eyeballs seen in Graves disease.

Fasting Blood Sugar (FBS)

Diagnostic blood test measuring circulating glucose levels after fasting for at least $8\text{ hours}$ to diagnose diabetes mellitus and gestational diabetes.

Continuous Glucose Monitoring System (CGMS)

System that continuously senses and records blood glucose levels over time.

Glucose Tolerance Test (GTT)

Diagnostic laboratory test that evaluates the body's physiological ability to handle a standardized glucose load.

Glycosylated Hemoglobin Test (HbA1c)

Blood test that measures the amount of glucose attached to hemoglobin to assess long-term glycemic control; elevated levels indicate poor glucose regulation.

Radioimmunoassay (RIA)

Sensitive laboratory procedure used to measure minute hormone concentrations in blood plasma.

Radioactive Iodine Uptake (RAIU)

Nuclear medicine imaging scan evaluating thyroid gland function and structure by measuring the absorption of radioactive iodine.

Multiple Daily Injections (MDI)

Diabetes management regimen consisting of administering several injections per day to supply basal or bolus insulin.

Thyroid Eye Disease (TED)

Autoimmune orbital condition associated with thyroid dysfunction, characterized by proptosis and inflammation of ocular structures.