24 - Kidney Histology Flashcards
Function of renal corpuscule
ultrafiltration of blood
Layers of glomerular filtration barrier
o Fenestrated capillary endothelium
o Basement membrane
o Podocyte layer of Bowman’s capsule
Function of proximal convoluted tubule
reabsorption
o Na+/K+ ATPase in basolateral membranes
o 70-80% of the water, Na+ and Cl-
o ~100% of amino acids and glucose
o some bicarbonate reabsorbed/ H+ secreted
o Larger proteins, carbohydrates - endocytosis
Appearance of PCT
Microvillus brush border, endocytotic vesicles and lysosomes, basal and lateral interdigitations
Function of loop of henle
creates and maintains high ionic concentrations in medulla
Structure of loop of henle
o Thin simple squamous epithelium
Descending loop of henle
permeable to urea, h20 but less to NaCl- absorbs water
Ascending loop of henle
impermeable to water, allows some NaCl diffusion
Structure and functionof thick ascending limb
simple cuboidal, actively transports Na+ with Cl- out of tubule without water→ hypotonic urine and hypertonic concentration gradient of NaCl in medulla
Function of distal convoluted tubule
– reabsorb H2O with ADH presence and electrolyte (Na, K, Cl) by aldosterone
Appearance of distal convoluted tubule
Simple, cuboidal epithelium, few microvilli or endocytotic vesicles
Function of juxtaglomerular apparatus
regulates BP and volume
Juxtaglomerular cells function
afferent arteriole sense decreases in blood pressure and secrete renin (renin- angiotensin- aldosterone system)
Macula densa
sense decreased Na+ content of distal tubule
Function of collecting duct
Similar to DCT
Final concentration of urine (ADH sensitive);
Electrolyte and acid base balance (aldosterone sensitive)
Urea diffusion helps maintain high solute conc of the medulla