BIOL 373 midterm 2 questions well answered to pass

BIOL 373 midterm 2

Why not only filter the 1% of filtrate that needs to be excreted? - correct answer ✔✔filtering all then
excreting selected solutes is easier because there isn't a need for specific transport mechanisms

-able to happen quickly



Why are the roles of the kidneys? - correct answer ✔✔1) regulation of ECF volume and blood pressure

2) regulates plasma osmolarity (Na+,CL-)

3) regulates ion balances

4) excretion of waste

5) regulates plasma pH

6) endocrine



Describe the urinary tract pathway - correct answer ✔✔1. fluid moves from plasma into nephrons
(hollow tubules) in the kidneys

2. nephrons modify the composition of the fluid as it passes through

3. modified fluid leaves the kidneys and enters hollow tube called ureter

4. ureters lead from kidney to bladder

5. bladder fills and expands until it conracts and expels urine through a single tube called urethra



What are the vascular elements of a nephron? - correct answer ✔✔renal artery

smaller arteries

1) afferent arteriole

2) glomerulus (capillaries)

3) efferent arteriole

4) peritubular capillaries

5) vasa recta (juxtamedullary only)

,What is contained in the cortex of the nephron? the medulla of the nephron? - correct answer
✔✔cortex:

-all Bowman's capsules

-PCTs

-DCTs

medulla:

-Loop of Henle

-collecting ducts



What are the tubular elements of the nephron in order? - correct answer ✔✔renal corpuscle (Bowman's
capsule + glomerulus)

proximal tubule

descending limb

Loop of Henle

ascending limb

distal tubule

collecting duct

to bladder



Describe renal circulation in general - correct answer ✔✔artery -> capillary -> vein -> capillary -> vein ->
heart

nephrons have 2 capillary beds (glomerulus capillaries and pertitubular capillaries)



What is the difference between renal circulation in juxtaglomedullary nephrons and corticol nephrons? -
correct answer ✔✔jutaglomerular nephrons go through vasa recta



Describe the detailed pathway of renal circulation - correct answer ✔✔abdominal aorta -> renal artery -
> branches of smaller arteries -> 1. afferent arterioles -> 2. glomerulus (capillaries) -> 3. efferent arteriole
-> 4. peritubular capillaries/ 5. vasa recta -> venules -> veins -> renal vein -> vena cava

, Overview of kidney function - correct answer ✔✔-kidneys process over 180 L plasma/day but only 1.5 L
secreted - 99% of fluid is reabsorbed

1) filtration

2) reabsorption

3) secretion



What is filtration? - correct answer ✔✔movement of water/solute from blood into tubules

-occurs in renal corpuscles

-once in tubules, filtrate will be excreted if not reabsorbed



What is reabsorption? - correct answer ✔✔movement of water/solute from filtrate back into blood
(peritubular capillaries)



What is secretion? - correct answer ✔✔removing molecules from blood, adding them to filtrate

-much more selective than filtration



Where does filtration occur? - correct answer ✔✔only at the glomerulus

-blood to lumen



What does urinary excretion depend on? - correct answer ✔✔filtration, reabsorption and secretion

amount of solute excreted = amount filtered - amount reabsorbed + amount secreted



filtrate at the renal corpuscle - correct answer ✔✔-filtrate is almost identical to plasma in composition
(isoosmatic with plasma, Na+ Cl-)

-minus blood cells and most of the protein



Reabsorption and secretion in the nephron - correct answer ✔✔-70% of filtrate and solute is reabsorbed
in proximal tubule (iso-osmotic reabsorption)

-fluid leaving ascending Loop of Henle is hypo-osmotic relative to plasma (at this point 90% of fluid has
been reabsorbed)