The Endocrine System

o Def: System of glands in various parts of the body that manufacture & secrete hormones into the bloodstream o hormones = chemical substances; Greek for “to excite”; affect other body cells o pituitary gland = just below hypothalamus; master gland that controls/turns on other glands in the endocrine system & releases a growth hormone o underactive pituitary = dwarf o overactive pituitary = giant

o Thyroid gland = in front, lower part of neck; produces thyroxin, which regulates metabolism o metabolize = to change food into energy o hyperthyroidism (too much thyroxin) = thin, nervous, unable to relax o hypothyroidism (too little thyroxin) = overweight, sluggish o Parathyroid gland = behind thyroid; regulates calcium metabolism o Thymus = controls lymph system; affects immune system

o adrenal glands = just above kidneys; release epinephrine & norepinephrine which activate the sympathetic nervous system (prepares body for emergencies & stressful situations) o Adrenal glands also release: o small amounts of sex hormone o corticoids, which control the salt balance in your body o Pancreas = curved around small intestine & stomach; produces insulin & regulates blood sugar o diabetes (not enough insulin) = too much sugar in blood o hypoglycemia (too much insulin)= low blood sugar o control both with diet; diabetics sometimes inject insulin

o Gonads = sex glands that produce sex hormones, make reproduction possible, & responsible for secondary sex characteristics o pubic & underarm hair, breasts in women, facial hair & deepened voice in men o Female gonads = ovaries (produce estrogen & progesterone) o Male gonads = testes (produce testosterone)

Hormonal/Endocrin e System-Brief Overview for Primary/Secondary Students: youtube Gigantism – youtube