The Endocrine System and homeostasis 2024 - Trainor Bio 30 IB S2025

Thyroid

An endocrine gland that produces hormones regulating metabolism, including thyroxine and triiodothyronine.

Adrenal Glands

Glands located on top of the kidneys that release hormones such as cortisol, epinephrine, and norepinephrine.

Insulin

A hormone secreted by beta cells of the pancreas that lowers blood glucose levels by facilitating cellular uptake of glucose.

Glucagon

A hormone secreted by alpha cells of the pancreas that raises blood glucose levels by stimulating the liver to convert glycogen to glucose.

Parathyroid Hormone (PTH)

A hormone produced by the parathyroid glands that raises blood calcium levels by breaking down bone and increasing calcium absorption.

Calcitonin

A hormone produced by the thyroid gland that lowers blood calcium levels by facilitating calcium uptake into bones.

Human Growth Hormone (hGH)

A hormone secreted by the anterior pituitary that stimulates growth, cell reproduction, and cell regeneration.

Epinephrine

A hormone produced by the adrenal medulla that increases heart rate, blood flow, and metabolism in response to stress.

Aldosterone

A mineralocorticoid hormone produced by the adrenal cortex that increases sodium absorption in the kidneys, thus increasing blood volume and pressure.

Melatonin

A hormone secreted by the pineal gland that regulates sleep-wake cycles and circadian rhythms.

Negative Feedback Loop

A process that counteracts change by reducing the output of a system, thus maintaining homeostasis.

Type 1 Diabetes

An autoimmune condition where the immune system destroys insulin-producing beta cells in the pancreas.

Type 2 Diabetes

A condition where the body's cells become resistant to insulin, often associated with obesity and lifestyle factors.

Thyroid-Stimulating Hormone (TSH)

A hormone released by the anterior pituitary that stimulates the thyroid gland to produce thyroxine.

Adrenocorticotropic Hormone (ACTH)

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

Leptin

A hormone secreted by adipose tissue that inhibits appetite by signaling 'fullness' to the hypothalamus.

Hypothalamus

A region of the brain that regulates hormone secretion from the pituitary gland and maintains homeostasis.

Feedback Mechanism

A biological process that regulates the output of a system in response to its current state.

Hormone Receptor

A protein on the surface or inside a cell that binds to a specific hormone to elicit a physiological response.

Pancreas

An organ that has both exocrine and endocrine functions, secreting digestive enzymes and hormones like insulin and glucagon.

Circadian Rhythm

The biological clock that regulates the sleep-wake cycle and other physiological processes on a roughly 24-hour cycle.

Homeostasis

The process by which biological systems maintain stability while adjusting to changing conditions.

Thyroid Hormones

Hormones produced by the thyroid gland, primarily thyroxine (T4) and triiodothyronine (T3), that regulate metabolism.

Cortisol

A glucocorticoid hormone produced by the adrenal glands that helps regulate metabolism and immune response.

Somatostatin

A hormone produced by the pancreas that inhibits the release of other hormones, including insulin and glucagon.

Glycogen

A stored form of glucose primarily found in the liver and muscles, utilized for energy when needed.

Pituitary Gland

The master gland of the endocrine system that regulates other glands and produces hormones such as growth hormone and TSH.

Adrenal Medulla

The inner part of the adrenal glands which produces catecholamines like epinephrine and norepinephrine in response to stress.

Insulin Resistance

A condition in which cells in the body become less responsive to insulin, often leading to Type 2 Diabetes.

Oxytocin

A hormone produced by the hypothalamus that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.

Diabetes Mellitus

A group of diseases characterized by high blood glucose levels due to insulin production or action issues.

Lipid-Soluble Hormones

Hormones that can pass through cell membranes easily and often bind to intracellular receptors, examples include steroid hormones.

Water-Soluble Hormones

Hormones that cannot easily cross cell membranes and typically bind to receptors on the cell surface, examples include peptide hormones.