MCAT Review - Hormones PDF

System Hormone In Response To: To Act On: To Cause: Endocrine Secreted from Gonadotropin-Releasing Hormone (GnRH) puberty Anterior Pituitary ↑ FSH and LH Strong Endocrine Corticotropin-Releasing Factor (CRF) Anterior Pituitary ↑ ACTH adrenocorticotropic hormone Strong Endocrine Thyroid-Releasing Hor...

System Hormone In Response To: To Act On: To Cause: Endocrine Secreted from Gonadotropin-Releasing Hormone (GnRH) puberty Anterior Pituitary ↑ FSH and LH Strong Endocrine Corticotropin-Releasing Factor (CRF) Anterior Pituitary ↑ ACTH adrenocorticotropic hormone Strong Endocrine Thyroid-Releasing Hormone (TRH) Anterior Pituitary ↑ TSH Strong Anterior Pituitary ↓ prolactin secretion Strong Anterior Pituitary ↑ GH Strong Hypothalamus Note: Understanding Endocrine Prolactin-Inhibiting Factor (PIF) aka dopamine Endocrine Growth Hormone-Releasing Hormone (GHRH) Endocrine Follicle Stimulating Hormone (FSH) GnRH Gonads ↑ follicate maturation; ↑ egg and sperm production Unsure Endocrine Luteinizing Hormone (LH) GnRH Gonads ↑ ovulation (when follicle releases the egg); ↑ testosterone Unsure Endocrine Adrenocorticotropic Hormone (ACTH) CRF Adrenal Cortex ↑ glucocorticoids (like cortisol) associated with stress Strong Endocrine Thyroid-stimulating hormone (TSH) TRH Thyroid ↑ thyroid hormones (T3 and T4) associated with basal Strong metabolic rate Endocrine Prolactin a decrease in dopamine suckling Breasts ↑ milk production and secretion inhibited by dopamine Strong ↓ the perception of pain in the brain; ↑ euphoria the "runner's high" experienced after intense aerobic exercise is the result of increased release of endorphins Anterior Pituitary Endocrine Endorphins Endocrine Growth Hormone (GH) aka somatotropin Endocrine ↑ bone and muscle growth; ↑ lipolysis Kidneys ↑ water reabsorption in the kidneys via ↑ permeability in the collecting duct via aquaporins ↑ blood pressure ↓ blood osmolarity due to ↑ blood volume ↓ urination (aka less water loss) Oxytocin Uterus ↑ uterine contractions during childbirth; ↑ pleasure feelings (bonding); ↑ milk secretion during lactation Triiodothyronine (T3) TSH Small Intestine; Blood ↑ metabolic activity; (rapid, shorter duration effects on metabolism. Derived from T4 via deiodonases. Clears cholesterol from plasma and ↑ glucose absorption from small intestine) Unsure Thyroxine (T4) TSH Small Intestine; Blood ↑ metabolic activity; (slower, longer lasting effects on metabolism. Clears cholesterol from plasma and ↑ glucose absorption from small intestine) Unsure ↓ blood calcium level " tones down [blood Ca] " Strong Posterior pituitary [produced by the hypothalamus but stored here] Endocrine Endocrine Endocrine Thyroids GHRH (also peaks during slow-wave sleep) Strong Muscles and Bones Anti-Diuretic Hormone (ADH / vasopressin) Endocrine Always Calcitonin High Blood Osmolarity (aka high salt concentration) Strong ADH release is inhibited by diuretics such as alcohol and caffeine. This is why you pee a lot (lose water volume) when consuming alcohol and caffeine. Unsure under positive feedback with itself Strong System Endocrine Secreted from Parathyroids Endocrine Hormone In Response To: To Act On: Parathyroid Hormone (PTH) Strong Strong Blood Angiotensin II Kidneys (distal convoluted tubule; collecting duct) ↑ Na+ and water reabsorption in kidneys via sodium-potassium channels (Na first, then water follows b/c physics) ↑ blood volume ↑ blood pressure ↓ K+ and H+ (via excretion) does not change blood osmolality, unlike ADH Unsure Epinepherine Liver, Muscle ↑ glycogenolysis in liver ↑ blood glucose level ↑ heart rate Strong Norepinepherine Liver, Muscle ↑ glycogenolysis in liver ↑ blood glucose level ↑ heart rate (aka the outer region of the adrenal gland) Aldosterone (mineralocorticoid) Adrenal Medulla (aka the inner region of the adrenal gland) Endocrine Understanding ↑ blood glucose level via gluconeogenesis ↓ inflammatory response ↓ immune function ↓ protein synthesis ↑ wakefulness Adrenal Cortex Endocrine Note: ↑ blood calcium level by promoting reabsorbtion of calcium into blood from the bones. activates Vitamin D and osteoclasts. Stress (exercise, cold, emotional, "flight-or-flight" response) Cortisol (glucocorticoid) Endocrine To Cause: Excess leads to mania. Deficiency leads to depression. Strong Endocrine Pancreas α-cells Glucagon when blood glucose levels are low Blood (during fasting) ↑ blood glucose via: ↑ glycogenolysis in the liver ↑ gluconeogensis ↑ lipolysis Unsure Endocrine Pancreas β-cells Insulin when blood glucose levels are high Blood (after a meal) ↓ blood glucose via: ↑ conversion of glucose into its storage form, glycogen (aka glycogenesis) ↑ uptake of blood glucose into tissue Unsure Endocrine Pancreas δ-cells Somatostatin Reproduction Testes Testosterone Reproduction inhibits BOTH Glucagon and Insulin Estrogen Reproduction Ovary/Placenta Immume Thymus Thymosin Digestion Stomach Ghrelin Digestion Fat Cells (in stomach) Leptin Digestion G-cells Gastrin Progesterone knowing that a meal is coming Orexin "statin" means inhibitory Strong maintains male secondary sex characteristics Strong maintains female secondary sex characteristics Strong ↑ growth/maintainence of the endometrium Strong ↑ T-cell development Weak ↑ appetite ↑ Orexin Strong ↓ appetite ↓ Orexin Strong ↑ HCl secretion ↑ gastric motility to mix contents Unsure System Secreted from Hormone In Response To: To Act On: To Cause: Note: Understanding ↑ Pancreatic Enzyme release into Duodenum ↓ motility through digestive tract to allow digestive enzymes to act on chyme; Digestion Duodenum Secretin Pancreous Strong regulates pH by: ↓ HCl secretion from parietal cells ↑ bicarbonate secreation from pancreas Digestion Duodenum Cholecystokinin (CCK) Amino Acids and Fat in Chyme as it enters duodenum Sleep Pineal Gland Melatonin Sleep Adrenal Cortex Cortisol RAAS; Blood Pressure Regulation Liver Kidneys Lungs RAAS; Blood Pressure Regulation Blood Pressure Regulation ↑ release of bile ↑ release of pancreatic enzymes ↑ satiety Strong ↓ light (night time in circadian rhythm) sleepiness Strong ↑ light (early morning in circadian rhythm) wakefulness Strong Renin-Aldosterone-Angiotensin System (RAAS) when the kidney detects a drop in blood pressure blood pressure homeostasis basically... the liver is constantly secreting a protein called Angiotensinogen. When the kidneys detect a drop in blood pressure, it secretes the enzyme Renin, which catalyzes a reaction that converts Angiotensinogen to Angiotensin I. Angiotensin I then travels throughout the circulatory system and when it reaches the lungs, it encounters an enzyme called ACE (angiotensin converting enzyme). ACE’s job is to convert Angiotensin I into Angiotensin II, which is the more potent hormone that brings blood pressure back up by various ways in order to restore homeostasis Angiotensin II being converted from Angiotensin I via ACE adrenal cortex posterior pituitary increases blood pressure when it is low via: ↑ Aldosterone ↑ ADH ↑ sympthetic activity ↑ vasoconstriction Heart Atrial Natriuretic Peptide (ANP) secreted from Neurotransmitters Nervous presynaptic & postsynaptic synapses of the parasympathetic nervous system Acetylcholine Nervous sympathetic nervous system Epinephrine Digestion hypothalamus Orexin when blood pressure is too high Pancreous, Brain decreases blood pressure when it is high via: ↓ Aldosterone ↑ urination (aka promotes water loss) ↓ water retention ↓ blood volume ↑ vasodilation this involves a system (RAAS itself is not a single hormone) People with high blood pressure are prescribed "ACE inhibitors" to prevent ACE from converting Angiotensin I into Angiotensin II, which helps to keep their high blood pressure low. Strong Strong antagonistic to Aldosterone Unsure Weak Weak Ghrelin, hypoglycemia ↑ appetite ↑ alertness lack of Orexin can result in cataplexy Unsure System Secreted from Hormone In Response To: To Act On: To Cause: Note: Understanding