BIOLOGY TOPIC 5.3 : HORMONAL COORDINATION IN HUMANS
negative feedback
blood glucose
diabetes
type 1
insulin injections
insufficient insulin produced by panaceas
type 2
obesity is a risk factor
body cells do not respond to insulin
exercise regime
controlled by pancreas
too high
stored in liver and muscles as glycogen
too low
pancreas releases insulin -> glucose moved back into the cell
pancreas secretes glucagon so glycogen is converted into glucose and then released
thyroxine
adrenaline
increases basal metabolic rate
flight or fight reponse
water balance
loss of water
kidneys
excreted in
diseases
acts on
filtration of blood
ADH is released by the pituitary gland when water level is too low
absorbs more water into the blood
excess amino acids deanimated in the liver, converted to urea
transplant
dialysis
urea diffuses out
blood is drawn into a machine, flows next to dialysis fluid, separated by a membrane
disadvantages: time consuming, restrictive diet, cannot be used undefinately
advantages: reduces urea, blood glucose level same, water and ion balance regulated
selective absorption of glucose, water and ions
sweat through skin
excess removed by kidney
lungs during exhalaration
reproduction
contraception
menstrual cycle
secondary sexual characteristics at puberty
IVF
oestrogen : stimulates ovulation
testosterone : sperm production
surgical sterilisation
intrauterine device
spermicidal agents
barrier eg: condom preventing meeting of sperm and egg
abstaining from sex around ovulation
injection, implant, patch of slow release progesterone
oestrogen + progesterone : maintain uterine lining
HT : oestrogen stimulates the release of LH
FSH : maturation of egg in the ovary
LH : stimulated ovulation of an egg
FSH stimulates the release of oestrogen from a mature egg
disadvantages
embyos are then injected into mother's uterus