chp 18 hormones in endocrine system

Releasing hormones

released by hypothalamus

stimulates the anterior pituitary gland to release hormones

Hormone will travel through blood or a portal system to the target organ stimulating cell to release hormone 2.

Thyroid Stimulating Hormone

Produced in - anterior pit

secretion stimulated by- thyrotropin RH from hypothalamus

targets the thyroid gland to release T3/T4

As the circulating TH levels increase TRH and TSH production declines

Adrenocorticotropic

produced- anterior pit

secretion- stimulated by corticotrophin RH from hypothalamus

Targets release of steroid hormones by the adrenal gland these targets cell produce glucocorticoids like Cortisol. This will affect glucose metabolism

Follicular

Produced in- anterior pituitary gland,

secretion stimulated by the GNRH from Hypothalamus

female-promotes ovarian follicle development works with LH to stimulate secretion of estrogen by ovarian cell

Male-stimulates nursing cell for cell maturation

inhibin released by testes and ovaries negative feedback loop

Luteinizing Hormone

produced by anterior pitutary

secretion stimulated by GNRH from hypothalamus

female- induces ovulation and promotes ovarian secretion of estrogen and progesterone

male- stimulate production of sex hormones by testes

both estrogen, progesterone and androgens inhibit GNRH

Prolactin

produced by anterior pituitary

secretion stimulated by PRH (release) and PIH (inhibit) by the Hypothalamus

stimulates mammary gland development in females (helps in milk production during nursing)

males regulate androgen production by making interstitial endocrine cell increase sensitivity to LH

when PRL rises PRH is inhibited and PIH is stimulated

Growth

produced in anterior pituitary

GH-RH releases and GH-IH inhibt secreted by hypothalamus.

stimulates cell growth and division by increasing the rate of protein synthesis acts directly/indirectly

indirect- the livers cells stimulate GH to synthesize release somatomedins (insulin like growth factors) these peptide hormones bind to receptors to stimulate tissue growth like in skeletal muscle

Melanocytes stimulating hormones

produced in pars intermedia

secretion stimulated in hypothalamus

only functional during fetal development and young children and pregnant instead MSH is produced locally within sun exposed skin.

stimulates melanocytes in skin to produce more melanin

dopamine inbibts release of MSH

Antidiuretic

produced in the hypothalamus

released into the bloodstream in posterior lobe of the pit.

an increase the of solute concentration of the blood or a decrease in the blood volume/pressure.

ADH acts on the kidney to retain water and decrease urination. Solutes follow water

at high concentration ADH can cause vasoconstriction which narrow blood vessels and elevates blood pressure

Oxytocin

produced in the hypothalamus

secretion stimulated by delivery

stimulates smooth muscle contraction in the wall of the uterus promoting labor and delivery. and after delivery promotes ejection of milk by stimulating contraction around cell and ducts of the mammary gland.

Parathyroid

produced by the parathyroid

secretion stimulated by parathyroid hormone

this causes an increase in calcium concentration in s the body by triggering other system like digestive to absorb more calcium and kidneys to retain calcium.

calcitonin

produced by the thyroid gland (C cells)

secretion stimulated by TSH

causes a lowering of calcium levels in the blood by excretion of calcium in the kidneys and prevents calcium absorption by the digestive tract. Stimulates bone growth and skeletal mineral deposition

corticosteroids

produced by all three zones of the adrenal cortex

vital steroids (lipid soluble) in target cells turn on transcription of certain genes.

Aldosterone

produced by the zona glomerulosa

secretion stimulated by a drop in blood sodium concentration and blood volume/pressure. but there is a increase in potassium

stimulates reabsorption of sodium ions by kidneys and also reabsorbs water and excretes potassium.

increase sensitivity to salt in taste bud making a person interested in eating salts

cortisol

produced in the zona fasciculata

secretion stimulated by ACTH from anterior lobe activates zona fasciculata to secrete glucocorticoids.

speed up rates of glucose synthesis and glycogen formation in the liver

cause adipose tissues to release fatty acids in the blood other tissues will use the fatty acids instead of glucose for energy.

Androgens

produced in the zona reticularis

secretion stimulated by ACTH the release in androgens

are important to female some androgens are converted to estrogen in the blood stream. stimulate development in the pubic hair before puberty

this promotes muscle mass and sex drive

males produce androgen in the testes

Catecholamines

produced in the adrenal medulla (secreted by exocytosis)

secretion stimulated by sympathetic nervous system and acclerates hormone release.

80% is Epinephrine 20% Norepinephrine

skeletal muscle- trigger mobilization of glycogen reserves this increase the breakdown of glucose for ATP

heart- increase heart rate and force of cardiac muscles contractions

fat- stored fats broken down to fatty acids

Melatonin

produced in the pineal gland by pineralocytes

secretion stimulated by visual pathways which affect rate of melatonin so increase in night vs day. Synthesizes melatonin from serotonin

influence circadian rhythm and inhibits reproductive function

if melatonin levels decrease at puberty can influence in human sexual maturation.

said to protect from free radicals

Insulin

produced by pancreatic islets

secretion stimulated by Beta cells

gets glucose into cells

is a peptide hormone that binds to receptors outside of the cells

this effects insulin dependent cells

which attach to phosphate to enzyme which give primary and secondary effects

Glucagon

produced in the pancreatic islets

secretion stimulated by alpha cells

increase in blood glucose levels which increase the rates of glycogen breakdown —> glucose to be released.

bind to receptors out of the cell —> adenlyate cyclase

atp—> camp for primary effects

calcitriol

produced in response to PTH and secreted by the kidneys or digestive system

is an active form of vitamin d3

this stimulates calcium and phosphate ions absorption.

stimulates formation of osteoblast (bone reabsorption)

and suppress PTH production

erythropotien

produced in the kidneys

secretion stimulated by a decrease in O2 levels in the kidneys.

stimulate red bone marrow to make RBC this helps increase blood volume and increase O2

Renin

produced by juxtaglomerular cells of glomerulus.

secretion stimulated by sympathetic simulation and a decrease in renal blood flow

starts as RAAS renin is then transformed to angiotensinogen a plasma protein. this then transform to angiotensin 1 uses ACE (Angiotensin-converting enzyme) converts to angiotensin 2—> stimulates thirst and increase in BP

angiotensin 2 can be also converted to aldosterone or ADH help retain salt and water

natriuretic peptides

produced in the heart with endo cells

secretion stimulated by blood volume in the heart increase causing the atria and ventricles cells to stretch

inhibits renin release in the kidneys and inhibits ADH /aldosterone suppresses thirst and prevents angiotensin and Nori from increasing BP

thymosin

produces hormones important in developing maturing immune systems defensive. this promotes the maturation of WBC

Leptin

produced when eating. adipose absorb glucose and lipids for storage and release leptin in blood

necessary of normal levels of GNRH and gonadotropin synthesis to take place

leptins bind to hypothalamus neurons involved with emotions and appetite control which gives sense of fullness

T3/T4

lipid soluble

made by follicle cell secreted into colloid

produced from the release of TSH which requires iodine

only 10-15% is in the form t3 rest is t4

enzymes in liver /kidneys convert t4 to t3

regulates body metabolism they help control how your body transforms food into energy.