2.68b osmoregulation

1. osmo-osmosis
2. regulation-to control 
3. We have cells in the body and ideally if the tissue fluid that surround these cells look like the ones in he diagram, this must be isotonic with the cytoplasm of these cells. 
4. This means that the amount of water going outside and inside of the cell is equal which further means that the cell will maintain its shape, size and function. 
5. The danger to the tissue is that the blood circulating to the tissue would be concentrated causing a hypertonic tissue fluid or it may be dilute causing a hypotonic tissue fluid. 
6. Hypertonic would remove too much water and hypotonic would add too much water to the cell. 
7. We want to keep the tissue fluid isotonic to the cell's cytoplasm. 
8. This achieved by controlling the composition of blood. 
9. Blood forms the tissue fluid. It is the role of the kidney to control the composition of blood 
10. Blood which circulates through our kidney, excess water, excess salts can be removed and excreted through the uretus.
11. If the kidney can control the content of water and salts in the blood, the kidney can keep the blood and therefore the tissue fluid isotonic with the cell's cytoplasm, maintaining the function of the cell