1
Q
What is excretion in a short sentence?
A
The removal of metabolic wastes from the body
2
Q
What are the diffrent excretory organs?
A
- Lungs
- Kidneys and bladder
- Liver and intestines
- skin
3
Q
What does the excretory organs excrete?
A
- lungs excrete Co2, water vapour and heat
- The kidneys excrete urine
- The liver excretes urea and bile pigments
- The skin excretes sweat via the sweat glands
4
Q
What does urine consist of?
A
- excess water
- mineral salts
- nitrogenous watse products, namely urea, uric acid and creatinine
5
Q
What does sweat consist of?
A
- excess water
- salts
- small amount of urea
6
Q
What is the origin of metabolic waste products?
A
- Co2 is formed as a product of cellular respiration
- Excess water is formed as a product of cellular respiration, as well as from the intake of fluids and food
- Urea is formed in the liver ffrom deamination of excess amino acids
- Uric acid is the end product of metabolism of nucleic acids
- Creatinine is formed from creatinine phosphate in the cells
- Bile pigments are formed in the liver during the breakdown of haemoglobin.
