Transporting Substances Around the Body

The heart is a muscular organ that pumps blood by contracting its walls; around the body. At the lungs, the blood picks up oxygen and loses carbon dioxide. It then returns to the heart, and is pumped to the rest of the body.

Arteries take the blodd from the heart and returns in veins. Capillieries go in between the organs and give blood to all the organs and cells.

Red blood cells contain a pigment called HAEMOGLOBIN. In the lungs, this combines with oxygen to form OXYHAEMOGLOBIN. 

When the cells are respiring, the OXYHAEMOGLOBIN breaks down releasing the oxygen for respiration. 

Red blood cells have no nucleus to allow more HAEMOGLOBIN.

Blood plasma transports; C02 to the lungs, Soluble products of digestion to all the living cells, and Urea to the kidneys, where it is excreted.

When exercising the muscles need more energy to contract. You need to increase the rate at which oxygen and glucose reach the muscle cells. Also C02 needs to be removed.

The heart rate increases and blood vessels dilate allowing more blood through.

Breathing rare increases to allow more 02 in and to get C02 out.

Glycogen; a storage compound of glucose may also be used up, which is present in the muscles.

if muscles are used over a long period of time they become fatigued. They begin to respire Anaerobically.

This is ineffective as it produces lactic acid as a waste product.

After the exercise, the lactic acid has to be broken down into C02 and water. This requires oxygen, thus a higher breathing rate, this is called OXYGEN DEBT.

The kidney filters the blood, excreting substances the body does not need, and keeping those it does.

After filtering the blood, substances such as mineral ions are reabsorbed.

Sometimes this is against the concentrations gradient, and requires active transport.

Dialysis replicates the work of the kidneys.

Dialysis fluid contains the same concentration of useful substances that the persons blood does not; e.g mineral ions. 

Dialysis restores the concentration of substances back to the norm, but needs to be carried out regularly, as toxins may build up. 

A donor kidney must be found, usually from a dead guy, and be a good TISSUE MATCH.

The immune system is likely to reject the new kidney so; 

Patients bone marrow is treated with radiation to prevent white blood cell production, 

Patient take immunosuppressant drugs.

Patient is kept in sterile conditions post - op.