The kidneys - SB7

Question 1

Each kindey contains thousands of tiny microscopic tubes called what?

Answer 1

nephrons

Question 3

where is urine made?

Answer 3

in the nephron?

Question 4

What are the stages of the making of urine in the nephron?

Answer 4

1. Blood flows in a network of capillaries called a glomerulus which runs inside the Bowman’s capsule of each nephron
2. Filtration occurs to make sure only small particles are let into the nephron
3. Filtrated fluid runs inside the nephron and selective re-absorbtion of useful subtances occurs here
4. Substances pass through first convoluted tubule via active transport
5. Water is re-absorbed via osmosis in the loop of Henle + collecting duct
6. remianing fluid flows into ureter - te substance is now called urine

Question 5

how is the nephron adapted for re-absorbtion of subtances

Answer 5

• large surface area of contact between nephron and capillaries
• Cell membrane of cells lining the first convoluted tube has tiny folds called microvilli - increases surface are: volume ratio
• Cells have protein pumps in the cell membranes that contai many mitochandria

Question 6

what else do the kindeys control besides getting rid of urea?

Answer 6

water content of blood

Question 7

What gland detects water content levels?

Answer 7

pituitary gland

Question 8

what does the pituitary gland release when there is too little water in the blood?

Answer 8

ADH

Question 9

what is the purpose of ADH in terms of water content in the blood?

Answer 9

changes the permiability of the collecting duct in nephrons + increase the concentration of the urine - meaning more water can be absorbed via osmosis from the collecting duct back into the blood