B12: Homeostasis In Action Flashcards
Control if your core body temp relies on the ———————————.
The thermoregulatory centre in the hypothalamus of the brain. (Extra info also comes from receptors on the skin)
What happens when your core body temp beings to rise?
Impulses are sent from the thermoregulatory centre to the body so more energy is transferred to surroundings to cool you down
What is vasodilation? And why does it happen?
It is when blood vessels that supply your surface skin capillaries dilate. Your skin flushes so you transfer more energy from your skin to the surroundings and cools you down and wars the air around you.
Why do you produce sweat when you’re too warm?
The after evaporates from your skin and transfers energy into the environment
What happens to cells when you’re too cold?
They slow down, don’t do enough respiration and begin to die.
What happens in your body when you’re too cold?
- capillaries in your skin constrict and reduce blood flow (vasoconstriction).
-sweat production is reduced or stopped
-skeletal muscles contract and relax rapidly (shiver)
What are the two main waste products your cells make?
Carbon dioxide and urea
Why must waste carbon dioxide be removed from the body?
Dissolved carbon dioxide produces and acidic solution
How is carbon dioxide removed from the body?
It diffuses out of the cells into the blood and then into the air into the alveoli in the lungs and then you breathe out the air.
Why must urea be removed from the body?
It’s poisonous and if it builds up it causes extensive damage to cells.
How is urea removed from the body?
It passes from the liver into the blood then filtered out of the blood by your kidneys and is passed out of the body in urine produced by the kidneys
How are water and mineral ions lost without control?
-water leaves the lungs through exhalation
-water, mineral ions and urea are lost in sweat
How are water and mineral ions lost with control?
-urea,excess water and excess mineral ions are lost through the kidneys then excreted through the urine
Why are the kidneys important?
If you are short of water, kidneys conserve it. If you have too much water, you produce lots of dilute urine.
What are two ways that kidney failure can be treated?
Dialysis and a kidney transplant
What happens in a dialysis machine?
-A persons blood leaves their body and flows between permeable membranes
-on the other side of the membranes there is dialysis fluid
-the dialysis fluid contains the same concentration of useful substances as healthy blood
What does treatment by dialysis do?
Restores the concentrations of useful dissolved substances to their normal levels
How long does dialysis take?
8 hours and it has to be done regularly because wasteful substances build up again
What are the disadvantages of dialysis?
-you have to follow a very strict diet
-you need to spend regular long intervals connected to the dialysis machine
What is the main problem with transplanting a kidney?
Possibility of rejection
Why does rejection happen?
The antigens on the surface of the donor organ are different to the patient’s. This could cause the immune system to attack the antigens on. The donor organ and destroy the donor kidney
How can rejection risk be reduced?
-matching the antigens of the patient’s to the donor
-drugs given to suppress their immune response for the rest of their lives (stops patients dealing with infectious diseases)
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How long does the average kidney transplant last for ?
9 years
