deck_593513 Flashcards
Glomerular endothelial cells
Aff and eff arteriolesFenestrated endotheliumPart of glomerular filtration barrier
Podocytes
Visceral layer of bowmans capsulePart of glomerular filtration barriermodified epithelial cells
Parietal layer of bowmans capsule
Squamous epithelial cellsLines urinary space
Intraglomerular mesangial cells
Modified smooth muscle cellsSupport glomerulusClean filtration barrier via phagocytosis
Extraglomerular mesangial cells
Modified smooth muscle cellsFunction unknown
JG cells
JG apparatus in Tunica media of aff and eff arteriolesModified smooth muscle cellsSyn and secrete renin
Macula densa cells
Cuboidal or columnar epithelial cellsIn dct at vascular poleMonitor urine volume and concentrationStim JG to release renin
Proximal convoluted tubule
Simple CuboidalSpecialized for resorption - most in proximal portionMicrovilli brush borderBasal infoldings, mitochondriaEndosomal and lysosomal compartments
Loop of henle
Squamous cellsType I - cortical nephronsType II, III, IV - juxtamedullary nephronDescending permeable to water, urea and ionsAscending less permeable
Distal tubule cells
Low simple cuboidal cellsNot permeable to water or ureaActively transport Na and Cl Apical nuclei, less microvilli and less mitochondria
Principal cells
Light cells of collecting ductSecrete KReabsorb NaImpermeable to water unless ADH is present
Intercalated cell
Dark cell of collecting duct (mostly cortical)Active transport of H - acid base controlImpermeable to water unless ADH present
Syn and secrete epo
Endothelium of peritubular capillary networkFrom efferent arterioles (w/ diaphragms)Cortical nephrons
Endothelium of vasa recta
From juxtamedullary nephron efferent arteriolesPermeable to water and saltCounter current exchange - maintain osmotic gradient
Transitional epithelium
Renal calyces, ureters, urinary bladder, portions of urethraTop layer is domed
Podocalyxin
Negatively charged protein in podocyte pediclesKeep large negative charges proteins from crossing filtration border
Vasa Recta
parallel with juxtamedullary nephronmaintains interstitial osmotic gradient Arteriola recta: lose H2O and gain salt - increase osmolalityVenula recta: gain H2O and lose salt -decrease osmolality
Glomerular filtration barrier
EndotheliumBasal Lamina (GBM): Podocytes (visceral layer bowman’s capsule)
Basal Lamina
Lamina Densa – physical barrier due to collagen IV, restricts molecules > 70,000 D’sLamina Rara externa – adjacent to podocyte processes, electrostatic barrierLamina interna – adjacent to endothelium also electrostatic barrier
Blood supply
Renal a. - Segmental artery - lobar artery - interlobar a. - arcuate a. - interlobular a. afferent a. glomerulus efferent a. vasa recta or peritubular
arterial portal system
glomerulus (cap bed) –> efferent arterioles –> peritubular capillaries and vasa recta
medullary rays
Cortical structures projecting from base of pyramidaxis of lobulesstraight portions of proximal and distal tubules and collecting ducts
Tubuloglomerular feedback at
•Macula densa cells monitor Na+ concentration•JG Cells secrete renin (receives signal from macula densa)•Renin converts Angiotensinogen (hepatocytes) to Angiotensin I•ACE (endothelial cells lung, kidney) converts Angiotensin I to Angiotensin II• Vasoconstriction of arterial smooth muscle• Posterior pituitary secretes ADH reabsorption of H2O• Adrenal cortex secretes aldosterone decrease excretion of NaCl in kidney
Metanephrogenic mesynchyme
nephron (develops distal to proximal)
