[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Physiology](https://durgical.com/en/physiology/) › Endocrine # Endocrine The hypothalamic–pituitary axes, thyroid, adrenal, endocrine pancreas and calcium. 27 pages ## Exam priority: high - [**Actions of cortisol** Mechanism · Cortisol is the lasting stress hormone: it raises glucose, damps inflammation and keeps blood…](https://durgical.com/en/physiology/actions-of-cortisol/) - [**Actions of thyroid hormones** Mechanism · Thyroid hormones set the pace of metabolism: with too much everything speeds up, with too little…](https://durgical.com/en/physiology/actions-of-thyroid-hormones/) - [**Aldosterone: actions and control** Regulation · Aldosterone makes the kidney keep sodium and excrete potassium and hydrogen](https://durgical.com/en/physiology/aldosterone-actions-and-control/) - [**Calcium regulation: PTH, vitamin D and calcitonin** Regulation · When blood calcium falls, the parathyroid releases PTH, which pulls it from bone, saves it in…](https://durgical.com/en/physiology/calcium-regulation-pth-vitamin-d-and-calcitonin/) - [**Islets and insulin: secretion and actions** Regulation · After a meal the pancreatic β cell releases insulin, which makes liver, muscle and fat store…](https://durgical.com/en/physiology/islets-and-insulin-secretion-and-actions/) - [**Physiology of diabetes and ketoacidosis** Mechanism · In diabetes insulin is missing or does not work well: glucose stays in the blood and, if insulin…](https://durgical.com/en/physiology/physiology-of-diabetes-and-ketoacidosis/) - [**The HPA axis and its circadian rhythm** Regulation · The brain sends CRH, the pituitary ACTH and the adrenal cortisol](https://durgical.com/en/physiology/the-hpa-axis-and-its-circadian-rhythm/) - [**The hypothalamic–pituitary system: overview** Concept · The hypothalamus gives orders to the pituitary, and the pituitary drives the thyroid, adrenals…](https://durgical.com/en/physiology/the-hypothalamic-pituitary-system-overview/) - [**The thyroid axis: reading TSH and free T4** Measurement · TSH is the thermostat: it rises when thyroid hormone is short and falls when there is too much](https://durgical.com/en/physiology/the-thyroid-axis-reading-tsh-and-free-t4/) ## Exam priority: medium - [**Appetite hormones: leptin, ghrelin and incretins** Regulation · Fat sends leptin to say «we have reserves»; the empty stomach sends ghrelin to say «eat»; the…](https://durgical.com/en/physiology/appetite-hormones-leptin-ghrelin-and-incretins/) - [**Blood glucose, glucose tolerance test and HbA1c** Measurement · Three tests show how well the body handles sugar: a fasting level, a curve after a sugary drink…](https://durgical.com/en/physiology/blood-glucose-glucose-tolerance-test-and-hba1c/) - [**Bone remodeling** Mechanism · Bone is rebuilt all the time: some cells dig out old bone and others fill the hole with new bone](https://durgical.com/en/physiology/bone-remodeling/) - [**Glucagon and the counter-regulatory hormones** Regulation · When glucose falls, glucagon and epinephrine raise it within minutes; cortisol and GH hold it up…](https://durgical.com/en/physiology/glucagon-and-the-counter-regulatory-hormones/) - [**Growth hormone and IGF-1** Regulation · The pituitary releases growth hormone in pulses, mostly in deep sleep; the liver answers with…](https://durgical.com/en/physiology/growth-hormone-and-igf-1/) - [**Hormones: types, receptors and feedback** Concept · Hormones are chemical messages in the blood](https://durgical.com/en/physiology/hormones-types-receptors-and-feedback/) - [**Measuring hormones: stimulation and suppression tests** Measurement · If a hormone is thought to be missing, the gland is stimulated; if it is thought to be in…](https://durgical.com/en/physiology/measuring-hormones-stimulation-and-suppression-tests/) - [**Prolactin and its control by dopamine** Regulation · Prolactin makes the breast produce milk](https://durgical.com/en/physiology/prolactin-and-its-control-by-dopamine/) - [**The adrenal cortex: zones, hormones and androgens** Concept · The outer layer of each adrenal gland has three zones: one makes the salt hormone, one the…](https://durgical.com/en/physiology/the-adrenal-cortex-zones-hormones-and-androgens/) - [**The adrenal medulla and catecholamines** Regulation · The core of each adrenal gland is a nerve relay that pours adrenaline into the blood in seconds…](https://durgical.com/en/physiology/the-adrenal-medulla-and-catecholamines/) - [**The endocrine stress response** Regulation · In injury, surgery or infection, the body releases cortisol, adrenaline and other hormones that…](https://durgical.com/en/physiology/the-endocrine-stress-response/) - [**The physiological response to hypoglycemia** Regulation · When blood sugar falls, the body first stops insulin, then releases glucagon and adrenaline, and…](https://durgical.com/en/physiology/the-physiological-response-to-hypoglycemia/) - [**The posterior pituitary: ADH and oxytocin** Regulation · The posterior pituitary releases two hypothalamic hormones: ADH, which makes the kidney save…](https://durgical.com/en/physiology/the-posterior-pituitary-adh-and-oxytocin/) ## For completeness - [**Bone as a calcium buffer: exchangeable calcium and mineral deposition** Mechanism · Bone holds a small, quickly available calcium store that steadies blood calcium within minutes…](https://durgical.com/en/physiology/bone-as-a-calcium-buffer-exchangeable-calcium-and-mineral-deposition/) - [**Hormone release patterns, clearance and receptor regulation** Concept · Hormones come in pulses and daily rhythms, are cleared at set rates, and target cells turn their…](https://durgical.com/en/physiology/hormone-release-patterns-clearance-and-receptor-regulation/) - [**Phosphate and FGF-23** Regulation · Phosphate builds bone and stores energy](https://durgical.com/en/physiology/phosphate-and-fgf-23/) - [**The pineal gland and melatonin** Regulation · In darkness the pineal gland releases melatonin, a signal that tells the body it is night](https://durgical.com/en/physiology/the-pineal-gland-and-melatonin/) - [**Thyroid hormone transport and deiodinases** Mechanism · Almost all thyroid hormone travels attached to proteins; only a tiny free part works](https://durgical.com/en/physiology/thyroid-hormone-transport-and-deiodinases/) ## A to Z - [A](https://durgical.com/en/physiology/a-z/a/) - [B](https://durgical.com/en/physiology/a-z/b/) - [C](https://durgical.com/en/physiology/a-z/c/) - [D](https://durgical.com/en/physiology/a-z/d/) - [E](https://durgical.com/en/physiology/a-z/e/) - [F](https://durgical.com/en/physiology/a-z/f/) - [G](https://durgical.com/en/physiology/a-z/g/) - [H](https://durgical.com/en/physiology/a-z/h/) - [I](https://durgical.com/en/physiology/a-z/i/) - [L](https://durgical.com/en/physiology/a-z/l/) - [M](https://durgical.com/en/physiology/a-z/m/) - [N](https://durgical.com/en/physiology/a-z/n/) - [O](https://durgical.com/en/physiology/a-z/o/) - [P](https://durgical.com/en/physiology/a-z/p/) - [R](https://durgical.com/en/physiology/a-z/r/) - [S](https://durgical.com/en/physiology/a-z/s/) - [T](https://durgical.com/en/physiology/a-z/t/) - [U](https://durgical.com/en/physiology/a-z/u/) - [V](https://durgical.com/en/physiology/a-z/v/) - [W](https://durgical.com/en/physiology/a-z/w/) [← Physiology](https://durgical.com/en/physiology/) Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given. Representative model, for educational purposes only. --- Source: https://durgical.com/en/physiology/areas/endocrine/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/physiology/areas/endocrine/