Kidney's

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Things are filtered via Nephrons

Ultrafiltration-

- A high pressure is built up

- This squeezes water, urea, ions, and sugar out of the blood

- This goes into the Bowman's capsule

- Big molecules such as proteins and blood cells stay in the blood

Reabsorption-

- useful substances are reabsorbed back into the blood

e.g. sugar - involving the process of active transport against the concentration gradient

- sufficient ions are reabsorbed - active transport

- sufficient water is reabsorbed

Release of wastes-

- the remaining substances continue out of the nephron

- they go down the ureter into the bladder as urine

If they don't work properly waste substances build up in the blood and your ability to control the levels of ions and water in our body is lost.

This can result in death.

Two ways people with kidney failure can be kept alive:

dialysis treatment

kidney transplant

Dialysis machines:

- the persons blood flows along a selectively permeable barrier (to ions and waste products) surrounded by dialysis fluid

- the dialysis fluid has the same concentration of ions and glucose as healthy blood would

- only waste substances such as urea and excess ions and water can diffuse across the barrier (dissolves ions and glucose wont be lost)

- 3 times a week for 3-4 hours

- may cause blood clots/ infection

Kidney Function

Kidney Failure