excretion

Question 1

what is excretion?

Answer 1

the removal of metabolic wastes

Question 2

how is excretion different to elimination?

Answer 2

excretion is the removal of wastes that have been produced by the metabolic activities of cells e.g. water, salts, urea, lactic acid, creatinine
- elimination is the removal of wastes that have never entered the cell. Elimination is the removal of undigested matter e.g.fibre

Question 3

why is excretion important?

Answer 3

because it maintains homeostasis, it does this by
-osmoregulation- maintaining water levels in the body
and
- removing toxic wastes e.g. urea, lactic acid

Question 4

list the organs of excretion

Answer 4

lungs, skin, kidneys, liver

Question 5

what do the lungs do in excretion?

Answer 5

excrete C02 from cellular respiration

Question 6

what does the skin do in excretion?

Answer 6

excretes sweat, salt, urea, lactic acid, the water in sweat has 2 other roles
1- protects internal organs
2- thermoregulation- maintaining body temp

Question 7

what do the kidneys do in excretion?

Answer 7

main functions
1- maintaining H20 levels in the body(by making you urine more or less concentrated)
2- excreting metabolic wastes- by removing them from the blood and putting them in the urine. wastes include nitrogenous wastes(urea, uric acid, creatinine) as well as drugs, hormones, electrolytes