Prosnephros
Week 4, then degenerates
Mesonephros
- Later contributes to male genital system
Metanephros
Ureteric bud
Metanephric mesenchyme/ blastema
Uteropelvic junction
- Most common site of obstruction in fetus (hydronephrosis)
Horseshoe kidney associated with
Compare unilateral renal agenesis and multicystic dysplastic kidney
Unilateral renal agenesis: ureteric bud fails to DEVELOP and induce differentiation of metanephric mesenchyme → complete absence of kidney and ureters; often diagnosed prenatally via ultrasound
Multicystic dysplastic kidney: ureteric bud fails to induce differentiation of metanephric mesenchyme → nonfunctional kidney consisting of cysts and connective tissue; often diagnosed prenatally via ultrasound
Duplex collecting system
Renal blood flow
Renal a. → segmental a. → interlobar a. → arcuate a. → interlobular a. → afferent arteriole → glomerulus → efferent arteriole → vasa recta/ peritubular capillaries → venous outflow
How to measure plasma volume
Radiolabeling albumin
How to measure extracellular volume
Inulin or mannitol
Filtration by fenestrated capillary endothelium
Size barrier
Filtration by fused basement membrane with heparan sulfate
Negative charge and size barrier
Filtration by epithelial layer consisting of podocyte foot processes
Negative charge barrier
What value can be used to calculate GFR
Inulin clearance, as it is freely filtered and is neither reabsorbed nor secreted.
Creatinine clearance is an approximate measure of GFR. Slightly overestimates GFR because creatinine is moderately secreted by renal tubules.
What value can be used to calculate effective renal plasma flow (eRPF)
Para-aminohippuric acid (PAH) clearance because between filtration and secretion there is nearly 100% excretion of all PAH that enters the kidney. eRPF underestimates true renal plasma flow (RPF) slightly.
Glucose clearance in a normal pregnancy
Normal pregnancy may decrease ability of PCT to reabsorb glucose and amino acids → glucosuria and aminoaciduria
Early PCT physiology
Thin descending loop of Henle physiology
Thick ascending loop of Henle physiology
Early distal convoluted tubule physiology
Collecting tubule physiology
How much Na+ is reabsorbed at various parts of the nephron