Excretion
- Created by: paddlergirl1306
- Created on: 16-04-14 10:12
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- Excretion
- Metabolic Waste
- Carbon
dioxide It is a product of aerobic respiration
- It is removed through the lungs when we breathe out
- Urea is produced in the liver when excess amino acids are broken down
- kidneys remove it from the blood and make urine - which is temporarily stored in the bladder
- Carbon
dioxide It is a product of aerobic respiration
- Water Balance
- We take in water through food and drink, also we get some when we respire
- We lose water in sweat, faeces, urine and when we breathe out.
- For
our cells to work properly, our water and mineral ion content has to be
maintained at the correct level
- If the ion and water content was to change to much water would be going in and out of the cells, then damaging them.
- Our body must control the the water we take in and the water we lose. This is done by the kidneys
- The kidneys maintain our water balance by producing urine of different concentrations
- Kidney Dialysis/ Transplants
- Dialysis
- Patients are connected to a dialysis machine which acts as an artificial kidney to remove most of the urea and restore/maintain the water and ion balance of the blood.
- Haemodialysis
- A machine takes over the function of the kidneys
- Blood is passed through a system of tubing made from a cellulose like substance that is partially permiable
- The tubing is surrounded by dialysis fluid - this contains glucose, sodium,useful minerals and has similar concentrations to normal blood plasma
- Advantages/ dissadvantages
- Available to all kidney patients
- No need for immune-suppressant drugs
- Patient must limit their salt and protein intake between dialysis sessions
- Expensive for the NHS
- Regular dialysis sessions – impacts on the patient’s lifestyle
- Transplants
- The main problem to kidney transplants is rejection.
- Precautions against rejection
- Tissue Typing- Only giving the kidney to patients who have the same blood group and antigens very similar to the donor kidney
- Immuno-suppressant drugs: Must be taken by patient for the rest of their life
- Unfortunately the drugs also suppress the immune system which can lead to infection
- Precautions against rejection
- Advantages/ Dissadvantages
- Patients can lead a more normal life without having to watch what they eat and drink
- Cheaper for the NHS overall
- Must take immune-suppressant drugs which increase the risk of infection
- Shortage of organ donors
- Kidney only lasts 8-9 years on average
- The operation carries considerable risks
- The main problem to kidney transplants is rejection.
- Dialysis
- Metabolic Waste
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