Endocrine System and Regulation of Metabolism

A complete set of vocabulary flashcards covering endocrine glands, hormones, hormone interactions, endocrine pathologies, and metabolic regulation mechanisms.

Neurohormones

Hormones secreted directly into the bloodstream by specialized neurons, such as releasing hormones from the hypothalamus.

Leptin

A hormone produced by adipose tissue that acts on the hypothalamus to suppress appetite.

Atrial Natriuretic Hormone

A hormone secreted by the heart that promotes the excretion of $\text{Na}^+$ and water in the urine.

Erythropoietin

A hormone secreted by the kidneys that stimulates red blood cell production in the bone marrow.

Synergism

A type of hormone interaction where multiple hormones act together to produce an effect that is greater than the additive sum of their individual effects.

Permissiveness

A type of hormone interaction in which a second hormone is required to create a permissive environment for a first hormone to exert its full expression.

Antagonism

A type of hormone interaction in which one hormone opposes the action of another, such as glucagon opposing insulin.

Cushing's Disease

A state of hypercortisolism typically caused by a pituitary tumor that autonomously secretes adrenocorticotropic hormone ($\text{ACTH}$).

Addison's Disease

A state of hypocortisolism characterized by the hyposecretion of all adrenal steroid hormones due to autoimmune destruction of the adrenal cortex.

Zona Glomerulosa

The outermost histological layer of the adrenal cortex that secretes mineralocorticoids, primarily aldosterone, to regulate mineral homeostasis.

Zona Fasciculata

The middle histological layer of the adrenal cortex that secretes glucocorticoids, primarily cortisol, to regulate glucose homeostasis.

Zona Reticularis

The innermost histological layer of the adrenal cortex that secretes weak androgens with masculinizing effects.

Chromaffin Cells

Specialized cells located in the adrenal medulla that secrete epinephrine ($80 nomination\text{\%}$ or $80\%$) and norepinephrine ($20\%$).

Exophthalmos

A bug-eyed appearance associated with Graves' disease, caused by immune-mediated enlargement of tissues and muscles in the eye socket.

Acromegaly

A condition caused by the oversecretion of growth hormone ($\text{GH}$) in adults, characterized by lengthening of the jaw, coarsening of facial features, and enlargement of hands and feet.

Osteoclasts

Bone cells responsible for bone resorption by secreting acid and protease enzymes that dissolve the calcified matrix and collagen support.

Parathyroid Hormone

A hormone released by chief cells of the parathyroid glands that increases blood $\text{Ca}^{2+}$ levels by mobilizing calcium from bone, increasing renal reabsorption, and stimulating calcitriol synthesis.

Calcitonin

A hormone secreted by parafollicular cells ($\text{C cells}$) of the thyroid gland that decreases blood $\text{Ca}^{2+}$ levels by inhibiting osteoclasts and increasing renal calcium excretion.

Osteoporosis

A metabolic bone disorder in which bone resorption exceeds deposition, leading to fragile and weakened bones.

Glucostatic Theory

A theory of food intake regulation stating that glucose utilization by hypothalamic centers regulates appetite and feeding behavior.

Lipostatic Theory

A theory of food intake regulation proposing that a signal from the body's fat stores modulates eating behavior to maintain body weight.

Glycogenolysis

The metabolic pathway involving the breakdown of stored glycogen into glucose.

Gluconeogenesis

The metabolic synthesis of glucose from non-carbohydrate precursors, such as lactate, glycerol, and amino acids.

Ketogenesis

The metabolic process of converting fatty acids into ketone bodies to supply energy when glucose and glycogen are unavailable.

Islets of Langerhans

Clusters of endocrine cells in the pancreas containing alpha cells (secreting glucagon), beta cells (secreting insulin and amylin), and D cells (secreting somatostatin).

Metabolic Syndrome

A condition defined by a combination of type 2 diabetes, atherosclerosis, and hypertension, diagnosed when a patient meets at least $3$ of $5$ clinical criteria.