Homeostasis Flashcards
what is homeostasis
the maintenance of the internal environment within an optimum range
changes to the water potential of the blood and tissue fluids cause cells to
shrink and expands as a result of water leaving or entering by osmosis
what is negative feedback
a change is counteracted to return back to normal
what is positive feedback
change is amplified so level moves further away from normal
what happens to enzyme activity when temperature falls below optimum range
enzyme activity decreases and causes rate of important reactions to slow down
in terms of bonds and enzymes what happens when body temperature rises above optimum range
enzymes denature at higher temperature causes the hydrogen bonds that maintain enzyme structure to break this alters active site so the enzyme can no longer catalyse reactions
in terms of respiration what will happens if the blood glucose levels are too low
respiration will slow and the amount of ATP will fall
how does carbohydrates affect blood glucose level
causes an increase In blood glucose concentration
which organ maintains the blood glucose levels
pancreas
how does exercise cause a decrease in blood glucose concentration (glucose)
glucose is being used in respiration to power muscle contractions
what occurs if there is a fall in blood glucose concentration (5M)
stimulus is detected by receptors
alpha cells in pancreas will secrete glucagon
glucagon will cause liver cells to convert glycogen into glucose
which raises BGC which is circulated back to the pancreas reducing alpha cell stimulation therefore reducing glucose production
what occurs if there is a rise in blood glucose concentration
insulin will be produced from beta cells in pancreas
insulin increases uptake of glucose by cells and its conversion to glycogen and fat
the fall in BGC reduced insulin production
what is glycogenesis
when BGC too high
glucose —->glycogen
glycogenolysis
BGC too low
glycogen—->glucose
glyconeogenesis
BGC too low
glycerol+amino acid. —–> glucose
what hormone do beta cells secrete when there is high blood glucose concentration
insulin
where are the beta cells located
islet of langerhans
in terms of insulin, enzymes, muscle cells, respiration explain how insulin lowers blood glucose concentration
insulin binds to the receptors in the muscle cell
causes a change in the tertiary structure of the glucose allowing more glucose into cells by facilitated diffusion
activation of the enzymes that convert glucose to glycogen and fat
the rate uptake of glucose by muscle cells increase
rate of respiration in muscle cells increase
what is the importance of insulin (2M)
lowering BGC
maintaining an optimum blood water potential
what do alpha cells detect
fall in BGC
what do alpha cells secrete when detecting a fall in blood glucose concentration
hormone glucagon
does glucagon increase or decrease blood glucose concentration
increases BGC