Nephron

Question 1

Functional unit

Answer 1

Group of cells which perform functions

Question 2

4 steps into filtering blood in the kidney

Answer 2

Filtration
Reabsorption
Secretion
Excretion

Question 3

Filtration

Answer 3

Small particles filtered out by the blood

Afferent and Efferent
A = large lumen
E = small lumen
Therefore there will be higher pressure in the glomerulus = more filtration

Question 4

Reabsorption + secretion

Answer 4

Substances to be kept by the body (RA)
Substances to be removed by the body (S)

• Peritubular capillaries surround the nephrons
• The Proximal convoluted tubule (pct)
  ATP - active = glucose and Na
  No Atp - passive = bicarbonate + H2O
• Loop of Henle
  Na (always active transport ) + H2O
  Descending = Passive t (H2O) due to diffusion of water
  Ascending = Active t (H2O) due to diffusion
• Distal convoluting tubule
  H2O, Na, HCO3 is actively reabsorbed (water, Sodium, Bicarbonate)
  Secreted at all three locations

Hydrogen, Potassium and creatine are secreted to balance pH

- Collecting duct
Absorbs H2O (passive), Drains urine

Question 5

Excretion

Answer 5

Removal of urine

Question 6

Urine

Answer 6

Contains mostly water, some salts, urea and bile pigments (recycled from erythrocytes) - creates the yellow colour
More water = diluted pigments = less yellow