Bio - 13.1

Question 1

excretion - definition

Answer 1

the removal of the waste products of metabolism and substances in excess of requirements

Question 2

excretory products - C02

Answer 2

lungs

Question 3

excretory products - urea

Answer 3

kidney

Question 4

excretory products - salt

Answer 4

skin

Question 5

excretory products - hormone

Answer 5

liver

Question 6

excretory products - alcohol

Answer 6

liver

Question 7

excretory products - drugs

Answer 7

liver

Question 8

urea - definition

Answer 8

• waste product produced in the liver
• from break down of excess amino

Question 9

process from protein to urea excretion (9)

Answer 9

1. protein is taken from diet
2. protease enzymes in stomach and small intestines breaks down into amino acids
3. amino acids absorbed into blood stream and goes to liver via HPV
4. deamination occurs - amino acids broken down to carbs and ammonia
5. ammonia it too toxic so its converted to urea
6. urea is realised into blood and transported to kidney
7. kidney filters blood and removes excess urea, water and ions to produce urine
8. urine flows from kidney through the ureters into bladder for storage
9. when sphincter muscles relax, urine is released thru the urethra

Question 10

parts of a kidney (4)

Answer 10

1. cortex
2. medulla
3. nephron
4. ureter

Question 11

nephron

Answer 11

• thousands of tiny tubules
• begins at cortex, loops down into medulla, back into cortex, goes down to medulla then joins up with ureter

Question 12

formation of urine

Answer 12

1. blood flows into kidney thru renal artery
2. it goes into a tiny, coiled tube called glomerulus
3. small molecules (water, urea, glu, ions) are filtered out of blood intro nephrons but big ones (RBC and protein) cant
4. useful substances (water and glu) are take back into blood for reabsorption
5. final liquid that flows out of the nephron is urea, water and salt (urine)