HOMEOSTASIS Flashcards
define homeostasis
the ability to maintain a constant internal environment
what things do we need to control within the body
temperature
pH
blood glucose
why do we need to control temperature
If temp is too high (40 degrees) enzymes will begin to denature
No longer works as a catalyst
Metabollic reactions are less efficient
why do we need to control pH
if pH is too high or too low enzymes will become denatured
H bonds break alters tertiary structure and active site changed
metabolic reactions slower
why do we need to control conc blood glucose
cells need glucose for energy
respiratory substrate for respiration
glucose conc also effects water potential
what happens if blood glucose conc is too high
if blood glucose conc is too high then water potential is reduced
water then moves out of cells and into blood via osmosis causing cells to shrivel up and die
what happens if blood glucose conc is too low
if blood glucose conc is too low then water potential is increased
cells unable to cary out normal activities as there isn’t enough glucose for respiration to provide energy
how do homeostatic systems respond when they detect a change
by negative feedback
what is negative feedback
a mechanism that that restores a level back to normal
eg body temp at 37 degrees - if too high it lowers it, if too low it increases it
what is an advantage of many negative feedback mechanisms
quicker response
more control
what is positive feedback
a mechanism that amplifies a change from the normal level
give an example of positive feedback
hypothermia
Low body temp
as body temp falls the brain doesn’t work properly and shivering stops which causes the body temp to drop even more
Therefore positive feedback has taken the body temp further away from the normal level and will continue to until action is taken
