Endocrine System Overview

These flashcards encompass key vocabulary and concepts related to the endocrine system from the lecture notes.

Endocrine Organs

Organs that secrete hormones directly into the bloodstream; includes the pineal gland, hypothalamus, pituitary gland, thyroid gland, parathyroid glands, thymus, adrenal gland, pancreas, ovaries, testes, and placenta.

Hypothalamus

A region of the brain that controls the pituitary gland and regulates various bodily functions, including hormone release.

Pituitary Gland

A small gland located at the base of the brain responsible for producing and releasing many hormones that control other endocrine glands.

Tropic Hormones

Hormones that stimulate other endocrine glands to release their hormones.

Negative Feedback Loop

A mechanism in which the output of a system suppresses or reduces the initial stimulus, maintaining homeostasis.

Corticotropin Releasing Hormone (CRH)

Hormone released by the hypothalamus that stimulates the anterior pituitary to release adrenocorticotropic hormone (ACTH).

Adrenocorticotropic Hormone (ACTH)

A tropic hormone produced by the anterior pituitary that stimulates the adrenal cortex to release cortisol.

Islets of Langerhans

Clusters of endocrine cells in the pancreas that contain alpha (glucagon), beta (insulin), delta (somatostatin), and F (pancreatic polypeptide) cells.

Insulin

A hormone produced by the beta cells of the pancreas that lowers blood glucose levels by promoting glucose uptake in cells.

Glucagon

A hormone produced by the alpha cells of the pancreas that raises blood glucose levels by promoting glycogen breakdown in the liver.

Hypersecretion

The excessive secretion of a hormone, which can lead to health issues such as Cushing's syndrome.

Hyposecretion

The insufficient secretion of a hormone, leading to conditions like diabetes mellitus due to lack of insulin.

Synergism

A situation where the combined effect of two hormones is greater than the sum of their individual effects.

Antagonism

The action of one hormone opposing the effects of another hormone.

Permissiveness

A condition where one hormone must be present for another hormone to exert its effects.

Thymosin

A hormone secreted by the thymus that regulates T-cell function and the immune response.

Cortisol

A steroid hormone released by the adrenal cortex in response to stress and low blood glucose levels.

Epinephrine

Also known as adrenaline, a hormone secreted by the adrenal medulla during stress that increases heart rate and energy availability.

Peptide Hormones

Hormones made of amino acids that bind to receptors on the cell surface, initiating a signaltransduction pathway.

Steroid Hormones

Hormones derived from cholesterol that can pass through cell membranes and bind to intracellular receptors, directly influencing gene expression.