Define the biological process of excretion.
Other than the kidneys, name one human organ that excretes metabolic waste products, and identify one waste substance it excretes.
The table below shows the concentration of two substances in healthy blood plasma and in urine.
| Substance | Concentration in blood plasma (g g\,g per 100 cm3) | Concentration in urine (g g\,g per 100 cm3) |
|---|---|---|
| Albumin | 4.0 | 0.0 |
| Glucose | 0.1 | 0.0 |
Name one nitrogen-containing metabolic waste product normally found in human urine.
With reference to the processes occurring in the glomerulus, explain why albumin is not present in the urine.
Explain why the body must not lose glucose in the urine, and describe how the cells of the nephron prevent this loss.
