Lecture 32 4/4/24 Flashcards
What are the characteristics of the Loop of Henle?
-in medulla
-parallel with the course of vasa recta
-U-shaped
-lining varies; simple squamous in thin segments, simple cuboidal in thick segments
What are the functions of the Loop of Henle?
-establish extracellular tonicity gradient
-concentration
-facilitation of ion and water exchange
How does the Loop of Henle length impact water retention?
the longer the Loop of Henle, the more water retention that occurs
What are the characteristics of the distal tubules?
-active transport: reabsorption, secretion, and exchange
-main target of aldosterone
-present in cortex only
-less numerous than proximal convoluted tubules
-lined by single layer of cuboidal epithelial cells
-contain specialized cells of macula densa
What are the functions of the distal tubules?
-adjust ion and urea concentrations
-maintain acid-base balance
What are the characteristics of the distal tubule epithelium?
-no brush border
-many mitochondria
-basolateral interdigitations
What is the location of juxtaglomerular apparatus?
site of physical contact between distal tubule and renal corpuscle in the same nephron
What is the function of the juxtaglomerular apparatus?
sensor for urine ion concentration and blood pressure
What are the macula densa?
chemoreceptors to sense sodium concentration in filtrate
How does the macula densa work?
-elevated NaCl triggers macula densa contraction of afferent arteriole
-leads to decreased GFR and volume concentration
What are the juxtaglomerular cells?
baroreceptors that sense blood pressure in afferent arterioles
How do the juxtaglomerular cells work?
-low blood pressure leads to the secretion of renin to the vessel lumen
-renin triggers aldosterone release, which increases sodium and water resorption in DCT
-resorption increases blood pressure
What are the characteristics of the collecting ducts?
-run from cortex to medulla
-continuous with papillary ducts
-primarily principal cells
-contain intercalated cells
What are the functions of collecting ducts?
-concentration
-acid-base
-immune response
-transportation of filtrate to papillary ducts into renal pelvis
How can cortex be distinguished from medulla?
-cortex contains proximal and distal tubules and collecting ducts
-medulla contains LOH and collecting ducts
What are the steps of renal blood flow?
-renal artery
-interlobular artery
-arcuate artery
-interlobular artery
-afferent arteriole
-glomerular capillaries
-efferent arteriole
-peritubular capillaries
-interlobular vein
-arcuate vein
-interlobular vein
-renal vein
What is the venous blood flow of the juxtamedullary nephrons?
descending vasa recta to ascending vasa recta
What is the clinical significance of renal blood flow?
-tubules are supplied by blood that has already gone through glomerulus
-blood cannot go through damaged/scarred glomerulus, leading to the tubules not being well perfused
What is the function of the renal pelvis and calyces?
-collects urine from the kidneys
-passes urine to ureters
What is unique about the renal pelvis and ureter in the horse?
they contain mucous glands
What are the characteristics of transitional epithelium?
-special type of stratified epithelium called urothelium
-only in the urinary system
-shape change with pressure allows structures to distend
-contributes immune properties
What are the characteristics of the ureters?
-carry urine to urinary bladder
-characteristic star shaped lumen
-oblique entrance into urinary bladder
What are the characteristics of the urinary bladder?
-stores urine
-urothelium mucosa
-detrusor muscle to allow bladder control
What are the characteristics of the urethra?
-carries urine from bladder to exterior
-mucosa transitions from urothelium to squamous
-muscularis transitions from smooth to skeletal muscle
