Pathophysiology: Endocrine System Disorders and Regulation

Vocabulary practice flashcards covering endocrine anatomy, feedback mechanisms, hypothalamic-pituitary-adrenal axis regulation, and key metabolic and hormone disorders.

Hypothalamus

The coordination and control center from the nervous to the endocrine system that controls the pituitary gland and synthesizes oxytocin and antidiuretic hormone (ADH).

Infundibular Stalk

The thin, triangular narrowing that serves as the communication and linkage point between the hypothalamus and the pituitary gland.

Antidiuretic Hormone (ADH)

A hormone produced by the hypothalamus and stored in the posterior pituitary that promotes the reabsorption of fluid by the kidneys to prevent water loss.

Oxytocin

A hormone made by the hypothalamus and stored in the posterior pituitary that triggers uterine contractions and acts as the milk let-down factor by moving milk during suckling.

Prolactin

An anterior pituitary hormone responsible for stimulating milk production in the mammary glands.

Growth Hormone (GH)

An anterior pituitary hormone that stimulates anabolic muscle growth, protein synthesis, and lipid mobilization while breaking down sugars.

Negative Feedback Loop

A regulatory mechanism that down-regulates, opposes, or reduces the original stimulus, accounting for approximately $99\%$ of physiological body functions.

Positive Feedback Loop

A self-amplifying regulatory cycle that enhances the original stimulus; the two primary physiological examples tested are blood clotting (platelet coagulation) and childbirth.

Primary Endocrine Disorder

An endocrine dysfunction that originates directly within the target hormone-producing endocrine gland itself.

Secondary Endocrine Disorder

An endocrine dysfunction resulting from abnormal stimulation or signaling by the pituitary gland.

Tertiary Endocrine Disorder

An endocrine dysfunction originating from impaired signaling or control in the hypothalamus.

Adrenal Medulla

The inner core of the adrenal gland connected to the sympathetic nervous system that secretes catecholamines, specifically norepinephrine, epinephrine, and dopamine.

Mineralocorticoids

Hormones produced in the outermost layer of the adrenal cortex (represented by 'salt'), primarily aldosterone, which stimulates sodium and water reabsorption.

Glucocorticoids

Steroid hormones produced in the middle layer of the adrenal cortex (represented by 'sugar'), such as cortisol, which regulate metabolism and response to stress.

Androgens

Hormones produced in the inner layer of the adrenal cortex (represented by 'sex') that function as weak male sex hormones promoting testosterone activity and muscle mass.

Cushing's Disease

A condition caused by an excess of corticosteroids, often due to chronic prednisone use, presenting with moon face, central obesity, buffalo hump, hypertension, hyperglycemia, thinning skin, and weakened bones.

Addison's Disease

An autoimmune disorder that destroys the adrenal cortex leading to deficient cortisol and aldosterone, characterized by fatigue, weight loss, hypotension, hypoglycemia, salt cravings, and skin hyperpigmentation (bronzing).

Addisonian Crisis

A life-threatening acute state of severe hypotension and severe hypoglycemia caused by the abrupt cessation or failure to taper corticosteroid therapy.

Graves' Disease

An autoimmune hyperthyroid condition caused by thyroid-stimulating immunoglobulins, resulting in high metabolic rate, weight loss, heat intolerance, tachycardia, and exophthalmos.

Hashimoto's Thyroiditis

A hypothyroid disorder marked by deficient $T_3$ and $T_4$ production, leading to depressed basal metabolism, weight gain, fatigue, cold intolerance, dry skin, brittle nails, and constipation.

Exophthalmos

Protrusion or bulging of the eyes caused by inflammatory swelling behind the eyes, unique specifically to Graves' disease.

Goiter

An abnormal enlargement of the thyroid gland resulting from thyroid overwork in either hypothyroidism or hyperthyroidism, as well as iodine deficiency; requires lab evaluation to identify the cause.

Type 1 Diabetes Mellitus

An autoimmune disease where the immune system destroys pancreatic beta cells in the islets of Langerhans, eliminating insulin production and causing cellular starvation, hyperglycemia, and fat breakdown.

Diabetic Ketoacidosis (DKA)

An acute, rapid-onset complication of Type 1 diabetes where severe lipid breakdown produces excess ketones, causing metabolic acidosis, Kussmaul respirations, fruity/acetone breath, and elevated blood glucose.

Type 2 Diabetes Mellitus

A metabolic disorder caused by receptor desensitization and insulin resistance, commonly linked to obesity and a sedentary lifestyle, leading to polyuria, polydipsia, and blood glucose levels that can exceed $600\,\text{mg/dL}$.

Hyperosmolar Hyperglycemic State (HHS)

A complication of Type 2 diabetes characterized by extremely high blood glucose ($> 600\,\text{mg/dL}$), severe dehydration, altered mental status, normal blood pH, and an absence of ketoacidosis.

Gestational Diabetes

Insulin resistance triggered by pregnancy hormones that carries risk of large babies ($> 9\,\text{pounds}$) and confers a $50\%$ lifetime risk for the mother of developing Type 2 diabetes.

Pineal Gland

An endocrine structure located on the epithalamus that secretes melatonin to regulate the circadian rhythm and light/dark sleep cycles.

Pheochromocytoma

A rare tumor of the adrenal medulla chromaffin cells that causes sympathetic hyperactivation, presenting with severe hypertension, tachycardia, diaphoresis, flushing, and resting tremors.

Trousseau's Sign

A clinical sign elicited by inflating a blood pressure cuff that induces carpal spasm, indicating hypocalcemia, frequently secondary to parathyroid gland removal or hypoparathyroidism.

Parathyroid Glands

Four small endocrine glands situated on the posterior surface of the thyroid gland that maintain and regulate serum calcium levels.

Acromegaly

A hypersecretory growth hormone disorder occurring in adults whose epiphyseal growth plates have fused, leading to enlarged bones and tissues in the face, hands, and feet.

Gigantism

A disorder caused by hypersecretion of growth hormone during childhood or adolescence before epiphyseal plates close, leading to excessive long-bone growth, tall stature, and delayed puberty.

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

A disorder characterized by excessive ADH release ('soaked inside'), leading to systemic fluid retention, fluid volume overload, and severe dilutional hyponatremia.

Diabetes Insipidus (DI)

A disorder caused by inadequate ADH activity ('dry inside'), resulting in inability to retain water, excessive urination (polyuria), extreme thirst (polydipsia), severe dehydration, and hypernatremia.