Endocrine

FunctionProduce hormones-released into bloodstreamMaintain homeostasisWorks through negative feedback: Obtaining a

desired response to a hormone inhibits further production or secretion of that hormone.

Example- when blood glucose levels are high, insulin is produced to remove glucose from blood. Glucose is stored in the cells. When blood glucose levels are low, glucagon is produced to cause cells to release stored glucose into the blood. When desired level is reached, hormone production is turned off.

Other example of negative feedback- when body doesn’t take in enough water it becomes dehydrated. Anti diuretic hormone(ADH) will be produced to tell large intestine to absorb as much water as possible.

Hormone- substance produced in one area (like a gland) that has an effect in another area or target cell.

Glands produce and release hormones into blood stream.

2 types of hormonesSteroid-fat soluble- move through cell

membrane easilyNonsteroid- need a receptor on cell

membrane to bind to it. This sends signal inside cell that causes another enzyme to act as messenger to cause effect.

Hypothalmus-in brainMaster gland- controls nervous system and

endocrine system.Will stimulate pituitary gland to release its

own hormones to stimulate other glands.

Pituitary Gland-in skullPituitary Gland

Hormone Action

Posterior ADH Kidneys reabsorb water

Posterior Oxytocin Uterine contractions and milk production

Anterior FSH Production of egg and sperm

LH Prepares uterus for implantation

TSH Release thyroxin from thyroid

GH Protein synthesis in cells

Prolactin Milk production

ACTH Stimulates adrenal cortex

Thyroid Gland

In base of the neckRegulates body’s metabolism by production

of ThyroxineToo much- hyperthyroidism- weight loss,

nervousnessToo little- hypothyroidism- weight gain,

lethargy

Parathyroid GlandLocated behind thyroidParathyroid Hormone regulates calcium

levels

Adrenal Gland-CortexAldosterone- regulates Na reabsorption and

excretion of KCortisol-controls rate of metabolism of carbs,

fats and proteins

Adrenal Gland- MedullaEpinephrine and NorepinephrineFight or flight reflexUnder control of your sympathetic and

parasympathetic nervous systemNormal conditions- parasympathetic systemFight or flight- sympathetic system signals

medulla to produce epinephrine and norepinephrine. Cause your heart rate to increase, breathing rate increase, eyes dilate, increase blood flow to muscles

PancreasInsulin- reduced blood sugar levelsGlucagon- increases blood sugar levels

Diabetes Mellitus- pancreas stops production (Type I)or insulin has no efffect(Type II)

Reproductive glandsTestes- produce testosterone-required for

sperm production. Also responsible for secondary sex characteristics

Ovaries- produce estrogen required for egg development and secondary sex characteristics. Ovaries also produce progesterone which is important in preparing the uterus for embryo implantation.