Renal Physiology Anatomy & Blood Flow

Question 1

Describe the structural organization of the functional unit of the kidney- the nephron (both vascular and tubular elements)

Answer 1

functional units-

filtration: renal corpuscle
- composed of Bowman’s capsule and glomerular capillary tufts

reabsorption/secretion: renal tubule

regulation: JGA
excretion: CDs

• renal artery supplies kidney
• all blood delivered o kidney passes through glomerular capillaries
• efferent arterioles supply peritubular capillaries OR vasa recta
• all blood exits kidney via renal vein

Question 2

overview kidney function

Answer 2

1. regulation ECF and BP
2. regulation osmolality
3. maintenance ion balance
4. homeostatic regulation of pH
5. excretion of wastes
6. production hormones (erythropoietin, renin)

Question 3

fluid movement along nephron

Answer 3

1. plasma volume enters afferent arteriole (100%)
2. 20% of volume filters into nephron (bowman’s capsule)
3. > 19% of fluid is reabsorbed into efferent arteriole
4. > 99% plasma entering kidney returns to systemic circulation
5. <1% of volume is excreted to external environment

amount filtered- amount reabsorbed + amount secreted = amount excreted

Question 4

measuring RBF

Answer 4

substance used must:

• largely be excreted by nephron (NOT REABSORBED)
• not metabolized/produced by kidney
• not toxic to body
  i. e. PAH- 20% filtered, extensively secreted
• measure concentration in urine with amount going in

tells us how much plasma is delivered to kidney

** RPF does not change if filtration is impaired, need to do it together with GFR