2. 2.5 concentration

4. Glomerulus The glomerulus is the functional unit of the kidney
It consists of Bowman’s capsule, the proximal tubule, the distal tubule and the collecting duct
A knot of small capillaries, the glomerulus carries blood to the capsule.

7. Blood is filtered through the glomerulus
Only fluid, ions and small molecules enter Bowman’s capsule
Blood cells and proteins remain in the blood

9. Most of the glucose, sodium and amino acids are reabsorbed in the proximal tubule
90% of the fluid is reabsorbed

11. Concentration
The extracellular gradient created by active chloride transport draws water from the collecting duct.
The permeability of the collecting duct is controlled by ADH
Only birds and mammals can excrete a urine that is saltier than the blood.