A&P CH. 16.9-11 THE ENDOCRINE SYSTEM AI STUDY GUIDE

What are the two main parts of the adrenal gland and their origins?

Adrenal cortex (glandular tissue; 3 layers) and adrenal medulla (nervous tissue; part of sympathetic nervous system).

What hormones are secreted by the adrenal cortex

mineralocorticoids (like aldosterone), glucocorticoids (like cortisol), gonadocorticoids (weak androgens)

What zone makes mineralocorticoids

Zona glomerulosa

what zone makes glucocorticoids

Zona fasciculata

what zone makes gonadocorticoids

Zona reticularis

What does aldosterone do?

Regulates Na+ and K+ in ECF, stimulates Na+ reabsorption (and water) by kidneys, increases blood volume and pressure, and stimulates K+ elimination by kidneys.

What are the major mechanisms controlling aldosterone secretion?

Renin-angiotensin-aldosterone mechanism, plasma K+ concentration, ACTH, and atrial natriuretic peptide (ANP).

What does cortisol do?

Maintains blood pressure, influences metabolism (raises blood glucose, fatty acids, amino acids), primary effect is gluconeogenesis, suppresses inflammation and immune responses.

How does cortisol respond to stress?

Increases blood glucose, fatty acids, and amino acids; encourages cells to use fat for fuel, saves glucose for the brain; suppresses immune system and inflammation; long-term stress can damage body systems.

What hormones does the adrenal medulla secrete and in what ratio?

Epinephrine (80%) and norepinephrine (20%), known as catecholamines

What are the effects of adrenal medulla hormones?

Vasoconstriction, increased heart rate, increased blood glucose, and blood flow diverted to brain, heart, and skeletal muscle

What hormone does the pineal gland secrete?

Melatonin

What does melatonin regulate?

Day/night cycles, physiological rhythms (body temperature, sleep, appetite), and timing of sexual maturation/puberty

What are the two major types of pancreatic islet cells and their hormones?

Alpha cells make glucagon; beta cells make insulin

What does glucagon do?

Raises blood glucose by stimulating glycogen breakdown (glycogenolysis), gluconeogenesis, and release of glucose from the liver.

What does insulin do?

Lowers blood glucose by promoting uptake into fat and muscle cells, inhibiting glycogen breakdown, and preventing glucose formation from amino acids/fats.

How do insulin and glucagon interact?

They act antagonistically to regulate blood glucose levels.

What are the two major types of diabetes mellitus?

Type 1: hyposecretion of insulin; Type 2: hypoactivity (insulin resistance).

What hormones do the ovaries produce and their effects?

Estrogens and progesterone for maturation of reproductive organs, appearance of secondary sexual characteristics, breast development, cyclic uterine changes

What hormone does the testes produce and its effects?

Testosterone; initiates male reproductive organ maturation, secondary sexual characteristics, sex drive, sperm production, and maintenance of reproductive organs.

What hormones does the placenta secrete?

Estrogen, progesterone, and human chorionic gonadotropin (hCG).

What are the main hormones from adipose tissue and their functions?

Leptin (appetite control), resistin (insulin antagonist), adiponectin (increases insulin sensitivity).

What hormones do enteroendocrine cells of the GI tract secrete?

• Gastrin (stimulates HCl release)

• Cholecystokinin (CCK; activates pancreas, gallbladder)

What is the role of ANP from the heart?

Decreases blood Na+, thus lowering blood pressure and volume.

What hormones do the kidneys release?

Erythropoietin (RBC production) and renin (activates renin-angiotensin-aldosterone system).

What does the skin produce for endocrine function?

Cholecalciferol (vitamin D precursor), converted to calcitriol (active form) to help absorb calcium from the intestine.