B3 - homeostasis Flashcards
(19 cards)
homeostasis is ….
maintaining a constant internal environment
homeostasis regulates …
blood glucose concentration
water content
body temperature
body temperature is controlled by the …
hypothalamus
when you’re too hot …
erector muscles relax, so hairs lie flat
lots of sweat, which transfers energy to the environment when it evaporates
blood vessels widen (vasodilation), allowing more blood to flow near surface and cool down
when you’re too cold …
erector muscles contract, so hairs stand on end, trapping an insulating layer of air
very little sweat produced
blood vessels narrow (vasoconstriction), so less blood is near the surface
you shiver, which needs respiration so transfers energy
What hormones control blood sugar levels?
insulin and glucagon
released from the pancreas
when blood sugar levels are too high …
insulin secreted by pancreas
glucose moves from blood to liver and muscles
liver turns glucose into glycogen
when blood sugar levels are too low …
glucagon secreted by pancreas
liver turns glycogen into glucose
glucose released into blood by liver
type 1 diabetes is when …
pancreas produces little or no insulin
people with type 1 diabetes need …
insulin therapy - injecting insulin into blood
- very effective
limit intake of food with lots of simple carbohydrates
take regular exercise
type 2 diabetes is when …
a person becomes resistant to insulin
type 2 diabetes can be controlled by …
a healthy diet
exercising regularly
possibly losing weight
drugs are available
water content is regulated by …
the kidneys
If water potential of tissue fluid is higher than inside the cell …
net movement of water into cell by osmosis
could cause cell to burst (lysis)
If water potential of tissue fluid is lower than inside the cell …
net movement of water out of cell by osmosis
cell shrinks
when water content is too high …
brain detects water gain
pituitary gland releases less ADH
so less water reabsorbed by kidneys
ADH stands for …
anti-diuretic hormone
excess water intake causes …
kidneys to excrete more water
lots of dilute urine
high salt intake causes …
kidneys to excrete more salt
concentrated urine
