Excretion in humans
Carbon dioxide is excreted through the lungs Excrete urea, excess water and ions are excreted through kidneys.
- Nephron — the functional unit of the kidneys
- Glomerulus — filtration from the blood of water, glucose, urea and ions
- Convoluted tubule — Where reabsorption of all glucose, some urea and some ions back into the blood occurs
- Loop of Henle — Reabsorbs most water depending on the needs of the body. The loop of Henle can adjust how permeable it is to water so maximise or minimise osmosis
- Urine — contains urea (toxic), excess water and excess ions
Liver:
- Assimilation of amino acids by converting them to proteins
- Urea is formed in the liver from excess amino acids
- Deamination – The removal of the nitrogen-containing part of amino acids to form urea.