Endocrine System Vocabulary Flashcards

A comprehensive vocabulary flashcard set covering key terms, gland functions, hormone types, and pathways of hormone action from the lecture notes.

Exocrine Glands

Ducted glands that possess tubes or ducts to transport their secretions to another part of the body or external surface.

Endocrine Glands

Ductless glands that produce hormones directly into the blood and lymph to be transported throughout the body.

Hormones

Chemical signals secreted by endocrine glands into the bloodstream to regulate intercellular communication, coordination, and homeostasis.

Positive Feedback Systems

Homeostatic control systems that intensify a physiological change until a set point is reached and the body returns to homeostasis.

Negative Feedback Systems

Homeostatic control systems that produce physiological changes that counteract a disruption to return the body to homeostasis.

Humoral Stimulus

A stimulus for hormonal secretion caused by changes in blood concentrations of non-hormone chemicals, such as nutrients or ions.

Amine Hormones

Hormones derived from the chemical modification of a single amino acid, such as thyroid hormones, epinephrine, and norepinephrine.

Peptide Hormones

Water-soluble hormones composed of short chains of linked amino acids, such as antidiuretic hormone and oxytocin.

Protein Hormones

Water-soluble hormones composed of long chains of linked amino acids, such as follicle-stimulating hormone and human growth hormone.

Steroid Hormones

Lipid-soluble hormones derived from cholesterol that travel in blood bound to transport proteins, including testosterone, estrogens, progesterone, and aldosterone.

Intracellular Hormone Receptors

Receptor proteins located inside a target cell that bind lipid-soluble hormones (like steroids and thyroid hormones) after they diffuse through the cell membrane.

Cell Membrane Hormone Receptors

Receptor proteins located on the outer surface of target cells that bind water-soluble, amino-acid derived hormones, initiating an intracellular signaling cascade of enzymes.

Infundibulum

The stem or stalk of tissue that suspends the pituitary gland from the hypothalamus.

Anterior Pituitary (Adenohypophysis)

The anterior lobe of the pituitary gland that synthesizes and secretes tropic and non-tropic hormones under the control of hypothalamic releasing and inhibiting factors.

Posterior Pituitary (Neurohypophysis)

The neural lobe of the pituitary gland that serves as a tissue extension of the hypothalamus, storing and releasing oxytocin and antidiuretic hormone.

Hypophyseal Portal System

A network of capillaries in the infundibulum that shunts hypothalamic releasing and inhibiting hormones directly to the anterior pituitary.

Tropic Hormones

Hormones produced by the anterior pituitary that target and regulate the secretion of other endocrine glands, including ACTH, TSH, FSH, and LH.

Adrenocorticotropic Hormone (ACTH)

An anterior pituitary tropic hormone that stimulates the adrenal cortex to secrete corticosteroid hormones such as cortisol.

Thyroid Stimulating Hormone (TSH)

An anterior pituitary tropic hormone that regulates the metabolic activity and secretion of thyroid hormones by the thyroid gland.

Follicle Stimulating Hormone (FSH)

A tropic hormone that stimulates the production and maturation of gametes (ova and sperm) and promotes ovarian follicle growth.

Luteinizing Hormone (LH)

A tropic hormone that triggers ovulation, stimulates estrogen and progesterone production by the ovaries, and stimulates testosterone production by the testes.

Growth Hormone (GH)

An anterior pituitary hormone that promotes protein synthesis, fat catabolism, and glucose-sparing, stimulating cell proliferation and tissue growth directly and via liver IGF-1.

Prolactin (PRL)

An anterior pituitary hormone that promotes mammary gland development during pregnancy and milk production post-birth.

Oxytocin (OT)

A hormone produced by the hypothalamus and released by the posterior pituitary that stimulates uterine contractions, cervix dilation, milk ejection, and parent-newborn bonding.

Antidiuretic Hormone (ADH)

A hormone produced by the hypothalamus and released by the posterior pituitary in response to high blood osmolarity to increase water reabsorption in kidney tubules.

Thyroid Hormone

Hormones ($T_3$ / triiodothyronine and $T_4$ / thyroxine) secreted by the thyroid gland that regulate basal metabolic rate, nutrient breakdown, ATP production, and body temperature.

Goiter

An enlargement of the thyroid gland that can arise from either excessive or deficient production of thyroid hormone.

Calcitonin

A hormone released by parafollicular cells of the thyroid gland in response to high blood calcium levels that inhibits osteoclasts and stimulates osteoblasts to build bone.

Parathyroid Hormone (PTH)

The major calcium-regulating hormone secreted by the parathyroid glands in response to low blood calcium levels that stimulates osteoclasts, increases renal Ca2+ reabsorption, and initiates calcitriol synthesis.

Calcitriol

Active Vitamin $D_3$, synthesized by kidney tubule cells under PTH stimulation, which stimulates the intestines to absorb calcium from digesting food.

Aldosterone

A mineralocorticoid produced by the zona glomerulosa of the adrenal cortex that increases renal retention of $Na^+$ and excretion of $K^+$, elevating blood volume and blood pressure.

Cortisol

A glucocorticoid produced by the zona fasciculata of the adrenal cortex that inhibits tissue building and breaks down stored nutrients to raise fuel levels and increase stress resistance.

General Adaptation Syndrome

The body's three-stage response pattern to stress, consisting of the Alarm Reaction, the Stage of Resistance, and the Stage of Exhaustion.

Glucagon

A hormone produced by alpha cells of the pancreatic islets in response to hypoglycemia that increases blood glucose levels through glycogenolysis, gluconeogenesis, and lipolysis.

Insulin

A hormone produced by beta cells of the pancreatic islets in response to hyperglycemia that lowers blood glucose levels by promoting cellular glucose uptake, glycolysis, and glycogenesis.

Prostaglandins

Locally acting lipid signaling molecules produced from cell membrane lipids that regulate blood pressure, stomach secretions, uterine contractions, and nerve impulse transmission.

Gastrin

A hormone produced by glandular tissue in the stomach walls that stimulates secretion of hydrochloric acid and digestive enzymes.

Secretin

A hormone produced by glandular tissue in the duodenum that stimulates the pancreas to release pancreatic digestive juice.

Thymosin

A hormone secreted by the thymus gland involved in the maturation and development of the immune system.

Melatonin

A light-responsive hormone produced by the pineal gland that regulates seasonal changes in animals and inhibits hypothalamic release of luteinizing hormone.