ch.23 urinary Flashcards
distal convoluted tubule
apart of the renal tubule
hormones mainly act on here
What hormones act on the distal convoluted tubule?
aldosterone, ADH, atrial natriuretic peptide
aldosterone
promotes sodium reabsorption and water reabsorption which decreases urine volume and maintains BP
ADh
promotes water reabsorption and maintains BP
atrial natriuretic peptide
released by right atria
promotes sodium and water excretion increasing urine output and decreasing BP
parathyroid hormone
increases blood calcium and calcium reabsorption
collecting ducts
adjust the concentration of urine
hypotonic urine
more water, less salt
water remains in urine, salt reabsorbed
hypertonic urine
more salt, less water
dehydration leads to increase in ADh, increases aquaporin channels
more water is reabsorbed and urine is more concentrated
countercurrent multiplier
on nephron loop, tubule
used to create a high osmolarity gradient
What are the three parts of the countercurrent multiplier?
descending limb and ascending limb
urea recycling
descending limb
reabsorbs water but not salt
ascending limb
reabsorbs sodium, potassium, chloride
maintains high osmolarity
recycling of urea
accounts for 40% of high osmolarity of the medulla
countercurrent exchange system
formed by vasa recta
maintains concentration gradient using descending capillaries and ascending capillaries
descending capillaries
water diffuses out of blood and NaCl diffuses into blood
ascending capillaries
water diffuses into blood and NaCl diffuses out of blood
urinalysis
the examination of the physical and chemical properties of urine