Nephrons

Question 1

Importance

Answer 1

-supplied with blood from the renal artery
-waste products are excreted whilst substances the body needs are reabsorbed into the blood

Question 2

3 processes

Answer 2

1.Ultrafiltration- removing substances from the blood
2. Selective reabsorption- reabsorbing the substances the body needs
3. Urine formation-substances which are not reabsorbed travel as urine along the nephron to the collecting ducts where the waste travels to the bladder

Question 3

Ultrafiltration

Answer 3

-blood reaches the glamolerus from the renal artery
-high blood pressure maintained
-always occurs in the Bowman’s capsule
-small molecules and ions are squeezed out of the blood and into the nephron
-larger molecules eg proteins stay in the blood

Question 4

Selective reabsorption

Answer 4

-happens in the proximal convoluted tubule
-simple ions, Amino acids and glucose diffuse into the blood via channel proteins
-occurs in the loop of Henle (reabsorption of water and salt)

Question 5

Counter current multiplier in the loop of Henle - Descending limb

Answer 5

-permeable to water
-water leaves the nephron by osmosis and is reabsorbed in the kidney
-as much water as needed in reabsorbed here

Question 6

Ascending limb

Answer 6

-permeable to ions
-the tissue around the loop has a high concentration of water
-sodium (Na+) and chlorine (Cl-) ions diffuse out of the nephron
-the concentration of Na+ and Cl- decrease further up the limb

Question 7

Distal convoluted tubules

Answer 7

-this is here the final reabsorption of ions and water occurs to adjust the water balance
-ADH effects the amount of water reabsorbed here