Hormones in mammals

secreted by endocrine glands (into the blood capillaries).
are transported in blood plasma.
regulate changes in the internal environment
help homeostasis
may promote actions or inhibit effects
cause slow effects which are longer lasting.
affect a specific target organs

3 main groups:
1) amines: e.g. adrenaline from the medulla of adrenal glands.
2)peptides and proteins e.g. insulin and glucagon
3) steroids e.g. testosterone and oestrogen

released due to 1 of 3 types of stimulus:
1)presence or change in concentration of a substance
2) presence of change in concentration of another hormone
3) nervous stimulation e.g. adrenaline secreted from the adrenal medulla

hormone-------------site produced------------when-----------effect
insulin---------------beta cells-----------high glucose conc'-----reduced blood sugar
glucagon------------alpha cells----------low glucose in plasma---increases blood sugar
adrenaline----------adrenal meulla------nervous stimulation----incrse bld glucse & mre blood 2
ADH----hypothalamus-strd in pit gland--low blood water---increase water absorption in kidney
FSH--------anterior pit gland---------------------stims osestrogn and follicles in ovar develope
LH---------------pituitary---------------------------------stimulates ovulation
oestrogen----------ovary----------------menstrual cycle-----------stims endometirum
progesterone-----ovary---------------menstrual cycle-----------maintains endometrium
oxytocin-----------------------------during child birth--------stimulates contractions
prolactin---------ant pituitary---------after birth--------stims mammaries to produce milk


Endocrine: ductless gland

Exocrine: has a duct