Homeostasis Flashcards
4 internal processes controlled by haemostasis
Water content
Ion content
Temp
Blood sugar
What is homeostasis
The process by which your body maintains a constant internal environment
3 waste products + how they are gotten rid of
CO2- lungs breathe out
Urea (produced by liver & is product if broken down amino acids)- removed from blood by kidneys.
Water/ion content- could damage or destroy cells- sweat
Describe the breakdown of amino acids
Amino acids—–dream inaction in liver—> ammonia—> urea–in blood to kidneys—–> urine
Name 3 things that happen in the liver
Excess amino acids into urea
Poisonous substances are detoxified
Old red blood cells are broken down, turned into iron and stored to make new red blood cells
What is the job of a kidney
Filter the blood
How does a healthy kidney produce urine
Filters blood (blood pressure forces down nephron)(proteins are too large)
Reabsorbs sugar
Reabsorbs any dissolved ions the body needs
Reabsorbs as much water as the body needs
Releases urea, excess ions and water as urine
The things that are reabsorbed= selective reabsorption.
How to balance water content in bodyq
Pituitary senses low water- by blood pressure
Releases hormone ADH
Causes kidneys to reabsorb more water- as ADH binds to receptors in kidney duct and makes them more permeable
More conc urine
If too high less ADH released (is a negative feedback system)
How does selective reabsorption happen?
Active transport
What is in urine
Urea
Excess salts
Excess water
Why do kidneys sometimes fail?
Low blood pressure-filtration doesn’t work properly
High blood pressure- damage filtration membranes
Infection- damage kidney tubules
Kidney stones= build up of pressure
What is wrong with kidneys failing
Toxins
Salts
Urea
Build up to dangerously high levels
Two ways to keep the patient alive after kidney failure
Dialysis
Transplant
How dialysis works
Arterial blood leaves arm
Passed through partially permeable membranes in dialysis machine. Surrounded by dialysis fluid
Clean blood renters arm
What is in dialysis fluid
Same conc of useful substances (glucose,mineral ions) as patients blood= don’t have to be reabsorbed.
However no urea so it diffuses out
How does a kidney transplant work
New healthy kidney (usually from a death but could be from a living donor)
Same tissue match
Placed in groin are with old ones left in
Must take immunosuppressant drugs to prevent rejection
What must you do to the dialysis fluid
Continuously change it in order to maintain a constant concentration gradient
Pros of kidney transplants
Keeps patient alive whilst waiting
Cons of kidney transplant
Expensive machinery Regular & lengthy hospital visits Disruption to life Long-term staffing costs Dietary restrictions
Pros of kidney dialysis
Independence restored
No dietary restrictions
Frees up dialysis machines
Normal kidney function restores
Cons of kidney transplant
Long recovery Long waiting lists Skilled surgeons required Risk of infection & rejection Immunosuppressant drugs
Human body temp
37*c
Why does body temp have to be kept constant
Enzymes to work
How is body temp monitored
By thermoregulatory centre in brain and thermoreceptors in skin
