1. HOMEOSTASIS The maintenance of a constant internal environment. The main body conditions we have to maintain are: 1.Water content/balance 2.Ion content/balance 3.Blood glucose levels 4.Temperature

2. We also have to remove 2 main waste products: 1.Carbon dioxide …………… 2.Urea …………………..

3. Water and ions get into the body by ……………… …….. Water and ions leave the body by …………… ……….. Why is it a problem if the water and/or ion balance in the body is wrong?

4. THE KIDNEYS The kidneys have 2 main roles in the body: 1.Removal of urea (waste). 2.Water and ion balance. These are completed by a 2 stage process: 1)Ultrafiltration ………………………… 2)Selective Reabsorption …………………………...

5. KIDNEY FAILURE What if your kidneys fail? There are 2 ‘choices’: Dialysis Kidney Transplant

6. DIALYSIS

8. Questions Why is the dialysis tubing made of a selectively/partially permeable membrane? Why does the dialysis fluid contain a solution of glucose and ions the same as in the body? Why does the dialysis solution have to be constantly replaced? A person undergoing dialysis will have to go through this 3 times a week for up to 4 hours at a time.

9. DIALYSIS Drawbacks to dialysis: 1. You have to follow a carefully controlled diet. 2. You have to spend regular, long sessions connected to a dialysis machine. 3. Urea builds up in the blood between dialysis sessions.

10. TRANSPLANTS The diseased kidney is replaced with a healthy one from either a living or a deceased donor. The main drawback is rejection by the immune system. Why? What can be done to help prevent this from happening?

11. TRANSPLANTS v DIALYSIS ADVANTAGES OF TRANSPLANTS Can live an almost completely normal life. Don’t have to control diet or spend hours attached to a dialysis machine. No build up of urea in the body. Cheaper in the long term than dialysis. ADVANTAGES OF DIALYSIS No chance of rejection. Cheaper short term. No risk from major surgery. Do not have to take immunosuppressant drugs for life. Less risk of infection. Do not have to wait for a donor kidney to become available.