Glomerular Filtration

Question 1

of blood entering glomerulus, how much is filtered?

Answer 1

20% filtered, and of this, 19% is reabsorbed into bloodstream

Question 2

what crosses GBM, crosses GBM but reabsorbed in proximal tubule, does not cross GBM

Answer 2

Crosses GBM

• Water
• Electrolytes
• Urea
• Creatinine

Crosses GBM but reabsorbed in proximal tubule

• Glucose
• Low molecular weight proteins (α2 microglobulin)

Does not cross GBM

• Cells (RBC, WBC)
• High molecular weight proteins (albumin, globulins)

Question 3

what arteriole has high hydostatic pressure?

Answer 3

afferent arteriole

Question 4

golden rule of circulation?

Answer 4

if have high resistance, pressure will be increased downstream and reduced upstream

Question 5

outline the methods of intrinsic and extrinsic control of the kidneys

Answer 5

intrinsic:

• afferent arteriolar vasodilation
• efferent arteriolar vasoconstriction

extrinsic:

• sympathetic VC nerves- afferent & efferent constriction
• circulating catecholamines- mainly afferent
• Angiotensin II- mainly efferent