Date post: | 27-Dec-2015 |
Category: |
Documents |
Upload: | sylvia-lambert |
View: | 218 times |
Download: | 0 times |
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
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.