Lecture 33-34: Urinary Microanatomy Flashcards
____secrete urine
kidneys
_____ convey urine
ureters
____ stores and discharges urine
bladder
_____ discharges urine
urethra
the outer layer of the kidney capsule is made up of what
fibroblasts and collagen fibers (protection)
the inner layer of the kidney capsule is made up of what
myofibroblasts
what encompasses the parenchyma of the kidney
cortex and medulla
what makes up the renal lobe
renal pyramid + adjacent renal cortex + 1/2 column
each renal lobe drains into _____
one minor calyx
the renal papilla is?
pyramid extension into the minor calyx
what is the area cribosa
surface of papilla w/ openings of papillary ducts
what is the path of urine
minor calyx –> major calyx –> renal pelvis –> ureter –> urinary bladder
what does the uriniferous tubule include
the nephron and collecting duct
what is the purpose of the urinary space in the renal corpuscle?
conducts the ultrafiltrate to renal tubules
what is the glomerulus composed of?
- fenestrated capillary bundle
- afferent arteriole (enters)
-efferent arteriole (exits)
what are the two layers of the glomerular capsule
parietal layer - simple squamous epithelium
visceral layer- layer of podocytes that covers the glomerulus
what are pedicels
secondary processes of podocytes that interdigitate b/w podocytes
what is the term for the gaps b/w pedicels
filtration slits
what specialized cells are in the renal corpuscle
mesangial cells
characteristics of the mesangial cells?
- modified smooth muscle cells
- secrete extracellular matrix (Mesangium) for support
- regulate glomerular distension (contraction)
- keep the glomerular filtration apparatus clean
Function of the proximal tubule
reabsorption of ions and fluids and secretion of calcitriol
calcitriol = increases uptake of calcium and increases its concentration in blood
histology characteristics of the proximal tubule
- simple cuboidal epithelium
- microvilli, irregular lumen
- lateral and basal folds - no clear cell borders
- high concentration of mitochondria, vesicles and lysosomes at the basal surface
what is the function of the Thin loop of Henle
absorption of fluid by countercurrent exchange with the vasa recta, concentration of urine
countercurrent exchange = gradient-dependent transport of fluid into blood
histology characteristics of thin loop of Henle
- simple squamous epithelium (thin) facilitates countercurrent exchange
- few short microvilli
Function of the distal tubule
- selective secretion and absorption of ions (osmoregulation)
Secretion to ultrafiltrate if high [ions] in blood
Absorption if low [ions] in blood
juxtaglomerular apparatus for sodium
histology characteristics of distal tubule
- simple cuboidal epithelium
- few short microvilli (smaller and more regular border than proximal tubule)
- later and basal folds - no clear cell borders
blood supply to kidney
- afferent arteriole (renal artery to glomerular capillaries)
- efferent arteriole (glomerular capillaries to cortical and medullar capillaries)
conduct urine into minor calices
collecting ducts
Predominant cells of the collecting duct that are stimulated by ADH to provide water permeability
light cells
cells of the collecting duct that are involved in acid-base balance. Secrete carbonate into urine to decrease blood pH. Secrete H+ into urine to increase blood pH
Dark cells
