The Kidney Flashcards
Significance of noncontinuous GBM
GBM separates podocytes from endothelial cells and from the mesangium
It doesn’t complete cover the endothelial cell so there is direct contact between endothelial and mesangium
SUBSTANCE IN BLOOD CAN GET TO MESANGIUM WITHOUT CROSSING GBM.
Three layers of GBM
lamina densa - central lamina rara interna - thin inner lamina rara externa - thin outer composed of Type IV collagen has negative charge - lets neutral and cationic through
Ducts of Bellini
collecting ducts empty into these, discharge urine through the papillae and into calyces
JGA componenets
1) Macula densa - thick ascending limb of loop of henle with closely packed nuclei
2) Extraglomerular mesangial cells - between macula densa and hilar arterioles
3) Terminal afferent arteriole and proximal efferent arteriole
ANGIOTENSIN AND RENIN SYNTHESIS AND SECRETION
Potter sequence
results from insufficient amniotic fluid oligohydramnios sequence decreased urine production -->less amniotic fluid --> fetus compression -flattening of face -low set ears -small receding chin -beak like nose -bent lower extremities -PULMONARY HYPOPLASIA - chest compression and decreased stimulus
Renal Agenesis
stillborn + Potter sequence
unilateral + no other anomalies –> hypertrophy
unilateral + kidney hypoplasia –>progressive glomerular sclerosis (secondary FSGS) from over worked nephrons
Renal hypoplasia
6 or less renal lobes
should differentiate from atrophy or scarring
oligomeganephronia results –> over worked –> FSGS
Renal ectopia
fails to migrate from pelvis
simple ectopia - drains normally into bladder
crossed ectopia - one kidney drained to contralater side and both are located on one side of body
horseshoe kidney
fused at lower pole
increased risk for pyelonephritis and obstruction because ureters are compressed
Renal dysplasia
hetertopic tissue present in mesenchyme (cartilage)
tubulues form cysts
usually accompanied by other abnormalities (atresia, agenesis, stenosis)
undifferentiated tubules and mesenchyme and islands of cartilage
4 types:
-Aplastic renal dysplasia: small misshapen dysplastic kidneys, difficult to ID, potter sequence if bilateral, hereditary
-Multicystic renal dysplasia: unilateral, renal enlargement, multiple cysts, mis-shapen kidney, MOST COMMON CAUSE OF PALPABLE MASS IN NEW BORNS, Rx surgery
-Diffuse cystic renal dysplasia: uniform sized cysts, preservation of kidney shape, can lead to potter sequence, hereditary
-Obstructive renal dysplasia: focal or diffuse, uni or bilat, cause by intrauterine obstruction to urine flow (valves, stenosis)
AD PKD
Enlarged and multicystic kidneys
mutations in PKD1 or 2 (POLYCYSTIN) lead to ciliopathy (disrupts calcium signaling, cell polarity, induce tubular epithelial cell proliferation)
cysts fluid - filtrate then from transepithelial secretion
arise from any portion of nephron, parenchyma atrophy and fibrosis occurs
ALSO hepatic, spleen, pancrease cysts and cerebral aneuryms
AR PKD
most die in utero because of potter sequence
children that are born have renal insufficiency and hepatic fibrosis with PH
mutations in PKHD1 gene (FIBROCYSTIN)
cysts have radial arrangement
interstitial fibrosis and tubular atrophy
liver - congential hepatic fibrosis
Cysts in COLLECTING DUCTS
Glomerulocystic Disease
isolated or in concert with another cystic disease AD- mutations in HNF-1B large or small kidneys small round cysts dilation of Bowmans capsule glomerular tuft distorted or immature
Nephronophthisis and Medullary Cystic Disease
Neph- AR, NPHP gene mutation (NEPHROCYSTINS - link primary cilia to PKD or PKHD products), onset before 18
3 forms : infantile, juvenile (most common), adolescent –> ESRD
Medullary - AD, onset adolescent, renal failure in adults, MCKD1 or 2 gene mutation (UROMODULIN)
polyuria and renal failure in fourth decade
can be accompanied by gout and hyperuricemia
BOTH - Cysts at corticomedullary junction, distal nephron portions
Atrophic tubules, thickened BM, loss of tubules
Present with polyuria, polydipsia, enuresis –> azotemia and renal failure follow
Medullary Sponge Kidney
major are bilateral
papillary cysts that arise from collecting ducts
flank pain, dysuria, hematuria or gravel in the urine
may predispose to secondary pyelonephritis
