The Endocrine Glands

Comprehensive vocabulary flashcards covering the anatomy, hormones, functions, and disorders of the major endocrine glands based on the lecture material.

Endocrine glands

Ductless glands that control cellular activities in tissues in distant portions of the body through chemical messengers called hormones secreted directly into the bloodstream.

Hormone

Derived from the Greek word “hormon”, meaning "set into motion"; these chemical messengers move through the bloodstream to target cells.

Posterior pituitary (neurohypophysis)

An extension of the nervous system (hypothalamus) via the infundibulum that secretes two neuropeptides: antidiuretic hormone (ADH) and oxytocin.

Antidiuretic hormone (ADH)

A small peptide also known as vasopressin that regulates water balance by increasing water reabsorption in the kidneys.

Oxytocin

A small peptide that causes uterine contractions during childbirth and allows milk to be released from mammary glands during nursing.

Anterior pituitary (adenohypophysis)

The portion of the pituitary gland regulated by the hypothalamus via releasing and inhibiting hormones; it secretes nine hormones including GH, TSH, and ACTH.

Growth hormone-releasing hormone (GHRH)

A peptide from the hypothalamus that targets anterior pituitary cells to increase growth hormone secretion.

Somatostatin (GHIH)

A small peptide, also known as growth hormone-inhibiting hormone, that decreases growth hormone secretion from the anterior pituitary and inhibits insulin and glucagon secretion in the pancreas.

Thyrotropin-releasing hormone (TRH)

A small peptide from the hypothalamus that increases thyroid-stimulating hormone (TSH) secretion.

Growth hormone (GH)

Also known as somatotropin, it stimulates protein synthesis, the breakdown of fats, glucose synthesis, and promotes bone and cartilage growth.

Pituitary dwarfism

A condition resulting from too little GH being produced during childhood, characterized by small stature.

Gigantism

A condition resulting from too much GH being produced during childhood, leading to extreme height.

Acromegaly

The overproduction of GH in an adult, resulting in larger than normal feet, hands, and face.

Thyroid-stimulating hormone (TSH)

A glycoprotein that targets the thyroid gland to increase the synthesis and release of thyroid hormones T3 and T4.

Triiodothyronine (T3)

The active and more potent form of thyroid hormone produced by follicular cells that increases metabolic rate and body temperature.

Thyroxine (T4)

Also known as tetraiodothyronine, a thyroid hormone produced by follicular cells that binds with nuclear receptors to initiate protein synthesis.

Calcitonin

A hormone produced by parafollicular cells of the thyroid that stimulates osteoblast activity and reduces $[Ca^{2+}]$ in blood when levels are elevated.

Myxedema

Swelling of the face and body resulting from subcutaneous mucoprotein deposits, often associated with hypothyroidism.

Exophthalmos

Protruding eyes resulting from connective tissue proliferation and deposits behind the eye, associated with hyperthyroidism.

Adrenocorticotropic hormone (ACTH)

A peptide that targets the adrenal cortex to increase the secretion of glucocorticoid hormones like cortisol.

Aldosterone

A mineralocorticoid produced in the zona glomerulosa of the adrenal cortex that increases the rate of sodium reabsorption by the kidneys.

Cortisol

A glucocorticoid produced in the zona fasciculata of the adrenal cortex that increases glucose synthesis and decreases inflammatory responses.

Adrenal Medulla

The inner part of the adrenal gland controlled by the sympathetic nervous system, secreting epinephrine and norepinephrine.

Beta endorphins

Peptides that act as an analgesic in the brain and inhibit gonadotropin-releasing hormone secretion, often produced during stress.

Melanocyte-stimulating hormone (MSH)

A peptide that targets melanocytes in the skin to increase melanin production, making the skin darker.

Parathyroid hormone (PTH)

A hormone secreted in response to low calcium blood levels that stimulates osteoclasts and promotes calcium reabsorption by the kidneys.

Pancreatic islets

The endocrine portion of the pancreas consisting of alpha cells (glucagon), beta cells (insulin), and delta cells (somatostatin).

Insulin

A protein hormone secreted by beta cells that increases the uptake and use of glucose and amino acids by tissues like the liver and muscle.

Glucagon

A polypeptide hormone secreted by alpha cells that increases the breakdown of glycogen and the release of glucose into the circulatory system.

Melatonin

A hormone secreted by the pineal gland that regulates the sleep/wake cycle (circadian rhythm) by increasing the tendency to sleep.

Thymosins

Hormones secreted by the thymus gland that aid in the differentiation and maturation of T lymphocytes.