Blood flow through kidneys

1

blood enters kidneys through branch of aorta (renal artery). Blood contains glucose and O2 and urea

1 (a)

blood in renal artery must have sufficient pressure or kidney will not be able to filter blood

1 (b)

blood may have to much Na+ or much H2O. Kidney removes whichever excess to maintain adequate blood volume and ion balance

2

Renal artery branches into interlobular arteries, further divide into afferent arterioles

3

Each afferent arteriole leads to network of capillaries called glomerulus. Fluid leaks out capillaries of glomerulus, large molecules and cells don’t fill through pores

4

Blood leaves capillaries of glomerulus via efferent artiole

5

blood from efferent arterioles enter peritubular capillaries which collect much of the water that was lost through glomerulusand drain into the renal vein.

6

Interlobular veins from peritubular capillaries lead to renal vein, which exit kidneys and returns blood to inferior vena cava

6 (a)

blood in renal vein has had all its urea removed and should have exactly the right amount of H2O and Na+