Renal

Question 1

Chronic renal artery stenosis causing significant renal hypoperfusion will lead to hyperplasia of what structures?

Answer 1

Juxtaglomerular cells (modified smooth m. cells) of the afferent glomerular arteriole

Question 2

How to calculate the total filtration rate for a substance and the excretion rate?

Answer 2

• F.R. = (Inulin clearance aka GFR) x (Plasma concentration of substance)
• E.R = (Filtration Rate) - (Tubular Reabsorption rate of Substance)

Question 3

CKD leads to hyperphosphatemia which can induce hypocalcemia via what 2 mechanisms?

Answer 3

• Phosphate binds free Ca²⁺ and precipitates in soft tissues
• Triggers release of FGF-23 (bone), inhibits renal expression of 1-alpha hydroxylase, reducing production of calcitriol and intestinal Ca²⁺ absorption

Question 4

What is the most common cause of unilateral fetal hydronephrosis?

Answer 4

Inadequate canalization of the ureteropelvic junction

Question 5

Which parts of the kidney arise from the ureteric bud?

Answer 5

• Collecting system of the kidney: including collecting tubules and ducts
• Major and minor calyces
• Renal pelvis
• Ureters

Question 6

Which parts of the kidney arise from the metanephric blastema?

Answer 6

• Glomeruli
• Bowman’s space
• Proximal tubules
• Loop of Henle
• Distal convoluted tubules

Question 7

What are the 2 most metabolically active segments of the nephron which are particularly vulnerable to acute tubular necrosis as a result of ischemia?

Answer 7

• Terminal (straight) portion of proximal tubule
• Thick ascending limb of the loop of Henle

Question 8

What is the effect of natriuretic peptides (ANP and BNP) on the kidney?

Answer 8

• Promote afferent dilation and efferent constriction which increases GFR
• Leads to increased Na⁺ and H₂O excretion

Question 9

Which renal disease presents with painless hematuria within 5-7 days of a URI and then subsides temporarily, returning ever few months or with another URI?

Answer 9

• IgA nephropathy (Berger disease)
• Biopsy showing: mesangial hypercellularity and mesangial IgA deposition