11/28: Urinary System II Flashcards
(81 cards)
What is the first segment of the renal tubule?
Proximal convoluted tubule
Where does the proximal convoluted tubule begin?
At the urinary pole of the glomerulus
Where is a majority of the glomerular filtrate reabsorbed?
PCT (70%)
What is the loop of henle continuous with?
PCT in cortex
Where does the loop of henle travel?
Into the medulla, then back to the cortex
Where does the loop of hele empty into?
Distal convoluted tubule (DCT)
What does the loop of henle form?
A hair-pin structure that dips down into the medulla
What 4 segments are contained in the loop of henle?
Pars recta (straight/thick descending limb of proximal tubule)
Thin descending limb
Thin ascending limb
Thick ascending limb
What do the thick and thin segments denote?
Epithelial change (cuboidal to squamous) in both the descending and ascending limbs
Where does the turn of the loop of henle occur?
In the thin segment within the medulla
Where does the tubule ascend after the turn in the loop of henle?
Towards the cortex parallel to the descending limb
What does the end of the loop of henle become?
The distal convoluted tubule near its original glomerulus
What is the area in the loop of henle where it runs parallel into capillary loops known as?
Vasa recta
What does the loop of henle serve to create?
High oscmotic pressure in the renal medulla via the counter-current multiplier system
What is high osmotic pressure important for?
Reabsorption of water in the later segments of the renal tubule, helps create hypertonic urine (excretion of excess solutes)
Where does the bulk of the loop of henle extend into?
Medulla; variable length
Describe the length of thin limbs
Long in juxtamedullary nephrons
Short in cortical nephrons
What kind of epithelium does thin limb have?
Simple squamous
What kind of epithelium does thick limb have?
Simple cuboidal epithelium
What does the pars recta have?
Brush border of apical microvilli (like PCT)
What is the loop of henle surrounded by?
Peritubular capillary network, vasa recta
What does the countercurrent multiplier function to generate?
High osmotic pressure in ECF of renal medulla via Na-K pumps in thick ascending limb of loop of henle
Where is extracellular Na quantities higher?
Medulla combined with water resorption by proximal convoluted tubule in cortex (cortico-medullary interstitial gradient)
What does counter current (exchange) multiple system of urine concentration result in?
Production of hypertonic urine
