Lecture 6: Histology (Cortes-Hinojosa) Flashcards
Order pronephros, mesonephros, and metanephros in order of evolution
pronephros –> mesonephros –> metanephros
Name 3 things found in the medullary rays*****
1) Proximal straight tubules
2) Distal straight tubules
3) Cortical collecting ducts
Name 3 things found in the cortical labyrinth*****
1) glomeruli
2) proximal convoluted tubules
3) distal convoluted tubules
What structures are in the CORTEX?**
Medullary rays (PST, DST, CD) and cortical labyrinth (PCT, DCT, glomeruli)
What structures can be found in all regions of the MEDULLA?**
Collecting duct
Thin tubule
PST
What structures are in the outer stripe of the medulla?**
PST, DST, collecting duct
What structures are in the inner stripe of the medulla?**
DST, thin limb of loop of Henle, collecting duct
Thick ascending limb of loop of henle =**
distal straight tubule
Thick descending limb of loop of henle = **
proximal straight tubule
What structures are in the outer medulla (outer + inner stripes)?
PST, DST, thin limb of loop of Henle, collecting duct (PST and DST are thick limbs!)
PST and DST are considered thin or thick limbs?
thick
What is found in the inner medulla?
thin limbs and collecting duct only
Structures found in both cortex and at least one region of the medulla
Collecting duct
PCT
DCT
Pathway of blood in the kidney
renal a.–> lobar a. –> arcuate a. –> interlobular a. –> afferent arterioles –> glomerular capillaries –> efferent arterioles –> peritubular capillaries –> vasa recta (to medulla)
Where are arcuate aa. found?
at corticomedullary junction
What is the mesangium?
Inner layer of the glomerulus within the basement membrane surrounding the glomerular capillaries. The cells are phagocytic and secrete the amorphous mesangial matrix
What drives solute and water reabsorption in the proximal tubule?
basolateral plasma membrane infoldings containing Na/K ATPase
Main fxs of loop of Henle
- generation and maintenance of medullary interstitial gradient
- regulation of H2O balance and urea excretion
3 main nephron segments of loop of Henle
1) PST
2) Thin limbs (w/ hairpin turn)
3) Thick ascending limb (DST)
what kind of animal secretes urea?
mammals
what kind of animal secretes uric acid?
birds and reptiles.
T or F: reptiles and birds don’t have Loops of Henle
true
tubule fluid bypasses what in short-looped nephrons? Why is this important?
inner medulla. Enhances water excretion
Advantage of long-looped nephrons
Water reabsorption enhanced because countercurrent exchange maintains medullary gradient
Thick limbs main fx
Na,CL resorbtion/K secretion
Thin limbs main fx
countercurrent exchange
fx of juxtaglomerular apparatus
regulates single glomerular filtration rate
fx of extraglomerular mesangium (ECM)
regulates glomerular blood flow via contraction
fx of macula densa
detection of signal related to solute contents
fx of Distal convoluted tubules (DCT)
Na/Ca/Mg resorption, dilution of tubule fluid
fx of Cortical collecting duct (CCD)
1) NaCl reabsorption
2) K secretion
3) vasopressin-sensitive H2O reabsorption
4) acid-base regulation
Fx of outer medullary collecting duct
1) K and acid secretion
2) K and NaCl absorption
Fx of medullary collecting duct
1) acid secretion
2) NaCl reabsorption
3) ADH-sensitive H2O and urea reabsorption
Where does collecting duct system start and end?
Starts in cortical medullary rays, ends where papillary rays empty into renal pelvis
What kind of epithelium in calyces, renal pelvis, ureters, and bladder?
Transitional epithelium
What kind of epithelium in urethra?
Stratified squamous epithelium
Pathway of urine from kidney to urethra
calyces –> renal pelvis –> ureters –> bladder –> urethra
How does ureter minimize accretion of CaCO3 crystals?
secretions of mucous glands in lamina propria
3 layers of tunica muscularis in the urethra?
1) inner longitudinal
2) middle circular
3) outer longitudinal
*in males, striated urethral muscle replaces the middle circular layer at the prostate
Which species have mucous glands in their urethra?
horses and cats
