B12 :Homeostasis in action Flashcards
what can affect your internal body temperature
-transfer of energy from muscles during exercise
-fevers
-change of external temperature
where is our core body temperature controlled
the thermoregulatory centre in the hypothalamus of the brain.
where do the thermoregulatory centre and hypothalamus get their extra info from
temperature receptors on the skin. They can detect a change as small as 0.5 degrees.
how does our body cool us down
-blood vessels dilate (vasodilation) and let blood flow more freely and transferring more heat to the surroundings.
-produce more sweat, water evaporates more
how does our body keep us warm
-blood vessels constrict (vasoconstriction), less blood flow, less energy transfer out of the body.
-sweat production is reduced or stopped
-skeletal muscles rapidly contract and relax (shiver), exothermic process to create heat.
what are the two main waste products
carbon dioxide and urea
what problem would carbon dioxide cause if it was left in the body
dissolved carbon dioxide produces an acidic solution, affecting optimum pH for enzymes.
side effect of exhalation
loss of water when moist air is forced out the body
what would happen if urea wasn’t disposed of?
it is poisonous and will cause extensive damage to the cells.
what happens to urea
-filtered out of the blood by the kidneys
-passed out of the body in the urine produced by kidneys.
when is urea produced
-eaten too much protein
-tissues are worn out
how is urea made
-amino acids broken into ammonia by the process of deamination (liver).
-ammonia is poisonous and is immediately converted into urea.
water loss that we cannot control
-leaving the lungs during exhalation
-lost during sweat
water loss we can control
-controlling the amount of water and mineral ions being put into the urine
what’s the function of the kidneys
-homeostasis of water levels/mineral ion levels
how do your kidneys work
-filter in all molecules that fit (NOT RBC or proteins)
-REABSORBES glucose, and a varied amount of water and mineral ions
what is the process of varied amounts of water and minerals absorbed called
selective reabsorbtion
if there is more ADH released, what happens to the amount of water reabsorbed
it is much more
how do people with kidney issues get further problems
toxins like urea build up and damage the cells
solutions to kidney problems
-dialysis
-kidney transplant
what does a dialysis machine do
carries out the functions of the kidney artifically.
downsides of dialysis
-takes a long time
-have to manage diet carefully
how does dialysis work
-blood leaves arm
-blood thinners prevent clotting
-waste products move into dialysis fluid (contains same concentration as healthy) by diffusion.
-RBC and proteins too big so are kept.
-clean blood flows through bubble trap to get rid of bubbles
-clean blood returns to patient.
process of blood and dialysis fluid flowing in opposite directions
counter-current flow, more efficient diffusion.
main problem with kidney transplant
the rejection problem
why does the rejection problem exist
antigens on donor organ are different to the recipients.
how to prevent rejection
-finding a close antigen match
-immunosuppressant drugs for life (also bad for other things)
how long does the average kidney transplant last for
9 years
dialysis or transplant?
-dialysis more available
BUT diet, and lots of time and more expensive
-Transplants risk of rejection, immunosuppressant drugs, risk of rejection. BUT more time good diet. cheaper in the long term.
