The endocrine system is by far the most complicated in the biology olympiad. There are tons of different hormones, tons of different functions carried out by one hormones, and tons of different regulators that control their secretion. So to help you memorize hormones faster and with less effort, we put together this list of mnemonics and diagrams. To be honest, mnemonics are essential to survival in your life as a student
- Divided into the anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis)
- All anterior pituitary hormones are peptides
- They are:
- Thyroid Stimulating Hormone (TSH or thyrotropin)
- Follicle Stimulating Hormone (FSH, a gonadotropin)
- Luteinizing Hormone (LH, a gonadotropin)
- Adrenocorticotropic Hormone (ACTH, or corticotropin)
- Growth Hormone (GH)
- Prolactin (PRL)
- They are:
So how to remember them? Well, easy! 😉
L – LH
A – ACTH
T – TSH
P – Prolactin
I – Intermedin (a.k.a. melanocyte-stimulating hormone or MSH)
G – GH
- TSH – target thyroid gland and stimulates secretion of thyroid hormone (TH)
- FSH – see below
- LH – see below
- ACTH – targets the adrenal cortex and causes the secretion of glucocorticoids (mainly cortisol)Functions of the anterior pituitary hormones
- GH – targets most body tissues and stimulates metabolism and growth of those tissues
- PRL – targets the breasts in females where it stimulates breast development and lactation.
- In males, FSH directly stimulates spermatogenesis – sperm look like “FiSH.”
- In females, FSH obviously stimulates ovarian follicles thus follicle–stimulating hormone. Follicles secrete estrogens which trigger an LH surge and ovulation.
- In males, LH stimulates androgen secretion so males become “Like Hairy Apes” (LH). Androgens are produce by Leydig cells which are stimulated by LH. These cells also indirectly stimulate spermatogenesis.
- In females, LH stimulates the formation of the corpus luteum (which secretes mainly progesterone and a bit of estrogen, which induce the formation of the endometrium). Remember 2 P’s: progesterone = pregnancy hormone
- Produces the amine hormone melatonin.
- Functions not well understood in humans but thought to play a role in regulating light-dark cycles.
- Produces two very different hormones.
- Follicular cells produce the amine-based thyroid hormone (TH).
- Parafollicular cells produce the peptide hormone calcitonin.
- Targets and functions of TH include:
- Regulate many metabolic functions.
- Essential for normal growth.
- Essential for the development of the nervous system.
- Essential for nervous system function in adults.
- Amplifies the effects of the sympathetic nervous system.
Calcitonin helps regulate blood calcium levels by inhibiting osteoclast activity, thus preventing excessive resorption of bone.
A cluster of small glands on the posterior of the thyroid gland.
Secrete the peptide hormone parathyroid hormone (PTH).
PTH is secretion is stimulated by a drop in blood calcium levels. PTH targets the following tissues:
Kidneys – PTH causes direct reabsorption of calcium.
Bone- PTH causes the resorption of bone.
Gut – PTH stimulates conversion of vitamin D to calcitrol, which regulates absorption of calcium by the intestines.
CalciTONin = “Tone it down” = Decrease in blood calcium
Parathyroid is the opposite
- Large at birth and increases in size until puberty. Decreases until unnoticeable in adults.
- Secretes the peptide hormones thymosin and thymopoietin.
- Function is poorly understood, but they play a role in the development of T-cell lymphocytes (hence the name). Adrenal glands
Small, paired glands that sit atop the kidneys.
Composed of an outer epithelial cortex and inner neuronal medulla.
Cortex secretes three classes of steroid hormones (mineralcorticoids, glucocorticoids, and androgens) and medulla secretes the catecholamines.
Important cortex hormones include:
Aldosterone – mineralcorticoid that causes the reabsorption of sodium and the secretion of potassium.
Cortisol – glucocorticoid that regulates metabolism, regulates the immune system, and facilitates the stress response.
Androgens – stimulates growth spurt early in puberty and controls female sex drive.
Secretes the catecholamines:
- Epinephrine – the sympathetic fight or flight response
- Norepinephrine – the sympathetic fight or flight response
How to remember?
A large mixed endocrine and exocrine gland that lies posterior to the stomach.
Region Hormone Produced
- Secretes two major peptide hormones, insulin and glucagon.
Islet cells contain _-cells the secrete insulin and _-cells that secrete glucagon.
Lowers blood glucose levels by stimulating glucose uptake by cells, glycogen synthesis by the liver and triglyceride synthesis by adipose cells. 2. Glucagon
Stimulates the breakdown of glycogen by the liver and the synthesis of glucose and ketones, thereby raising blood glucose levels. Ovaries
- Secrete the female steroid sex hormones estrogen and progesterone and the peptide hormone inhibin.
- Estrogen is important for egg development inside the ovarian follicles.
- Progesterone is important after ovulation for maintaining the integrity of the uterine lining and during pregnancy.
Inhibin regulates the secretion of FSH from the anterior pituitary in a negative feedback
*Be sure to view the animation of the ovary/uterine cycles. Testes
- Secretes the male steroid sex hormone testosterone and the peptide hormone inhibin.
- Testosterone aids in the development of gametes, is responsible for secondary sex characteristics, and controls libido.
Inhibin regulates the secretion of FSH by the anterior pituitary.
Page 4. Endocrine Tissues: Hormones and Functions
*Be sure to review all the endocrine tissues listed on this page.
- Endocrine tissues are composed of groups of endocrine cells that are found in glands that are not specifically endocrine glands.
The endocrine tissues include the following: hypothalamus, heart, stomach, small intestine and
- Has clusters of neurons that secrete neurohormones into the circulation.
- The paraventricular and supraoptic nuclei secrete hormones into the posterior pituitary where they are released into the blood.
The posterior pituitary hormones are:
- Oxytocin – a peptide that stimulates contractions of the uterus during labor and promotes milk ejection by the mammary glands.
- Antidiuretic Hormone (ADH) causes the kidneys to reabsorb water and has effects on blood pressure.
- The ventral hypothalamic neurons secrete releasing hormones that travel via the hypothalamic portal system into the anterior pituitary where they stimulate or inhibit the production of anterior pituitary hormones.
The releasing hormones of the ventral hypothalamus are:
- Thyrotropin releasing hormone (TRH)
- Growth hormone releasing hormone (GHRH)
- Somatostatin – inhibits secretion of GH
- Gonadotropic releasing hormone (GNRH)
- Dopamine (DA) converts into prolactin inhibiting hormone (PIH)
- Corticotropic releasing hormone (CRH)
Complete the following table.
GnRH DA (PIH)
Specialized cells of the atria secrete the hormone Atrial Natriuretic Peptide (ANP).
ANP causes the kidneys to excrete excess sodium and therefore helps to regulate blood
pressure and blood volume.
Cells lining the stomach secrete the peptide hormone gastrin.
Gastrin travels via the bloodstream back to the stomach where it stimulates the release of
HCl and growth of the stomach lining.
Gut (Small intestines)
The upper portions of the small intestine produce four hormones:
- Cholecystokinin (CCK) – stimulates secretion of bile by gallbladder, stimulates secretions of digestive enzymes of pancreas, and promotes growth and maintenance of pancreas and gallbladder.
- Secretin – causes the gall bladder and pancreas to secrete bicarbonate ion into the small intestines where it neutralizes acidic chyme from the stomach.
- Glucose dependent insulinotropic peptide (GIP) – causes the pancreas to secrete insulin when glucose is present in the small intestine.
- Motilin – released about every 90 minutes and causes the smooth peristaltic waves that sweep food toward the terminus of the small intestine.
Activates the peptide erythropoietin and the steroid calcitrol.
1. Erythropoietin – stimulates the red bone marrow to produce new RBC’s.
|Hypothalamic Hormone||Target||Pituitary Hormone||Target||Response of Endocrine Gland/ Target Tissue|
2. Calcitrol – The active form of vitamin D formed in response to PTH. It aids in the absorption of calcium by the intestines.
Digestive system hormones:
Gastrin from Gastric mucosa works on Stomach Food in stomach, psychic factors Increased HCl secretion & gastric emptying
Cholecystokinin (CCK) Duodenal mucosa Gallbladder & pancreas Amino acids, peptides, fatty acids in duodenum Contraction of gallbladder & secretion of pancreatic juice
Secretin Gastric mucosa Pancreas Acid in duodenum Increased bicarbonate secretion
Enterogastrone (gastric inhibitory peptide) Duodenal mucosa Stomach Fat digestion products in duodenum Decreases gastric emptying
Images: The Pituitary Gland and Hypothalamus by Rice University is licensed under a Creative Commons Attribution 4.0 International License, https://opentextbc.ca/anatomyandphysiology/chapter/17-3-the-pituitary-gland-and-hypothalamus/