APK Exam4 Ch18

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  1. What are the functions of the urinary system? (5) (4 are regulatory)
    • Regulate
    • Plasma ionic composition
    • Plasma vol
    • Plasma osmolarity
    • Plasma pH
    • Remove metabolic waste and foreign substances from plasma
  2. Secondary functions of kidneys include secretion of ___ and ____, activation of ___, and ____ (involved in metabolism).
    • erythropoietin, renin
    • Vit D3 to calcitriol
    • gluconeogenesis
  3. Kidneys: ___ urine
    Ureters: ___ urine from ___ to ____
    Bladder: ___ urine
    Urethra: ___ urine from ___ to ___
    • form
    • transport; kidneys to bladder
    • store
    • excrete; bladder to outside body
  4. Smallest functional unit of kidney
  5. ___ allows us to conserve water
    Loop of henle
  6. 4 steps of renal processes
    • 1. Glomerular filtration: from glomerulus to Bowman's capsule
    • 2. Reabsorption: from tubules to peritubular capillaries
    • 3. Secretion: from peritubular capillaries to tubules
    • 4. Excretion: from tubules out of body
  7. What are the two parts of the renal corpuscle?
    Bowman's capsule and glomerulus
  8. Does the portion of cardiac output the kidneys
    receive match the portion of body weight the kidneys represent?
    No, kidneys are less than 1% body weight, but receive 20% of cardiac output at rest
  9. Cortical nephron is located primarily in ___ but a juxtaglomerular nephron is located in both cortex and medulla (b/c loop of Henle dips deep in medulla)
  10. Mvmt of protein-free plasma from glomerulus to Bowman's capsule
    Glomerular filtration
  11. Volume of plasma filtered per unit of time. What is normal?
    • Glomerular filtration rate (GFR)
    • 180 L/dy (or 125 mL/min)
  12. Epithelial cell of Bowman's capsule
  13. Why is GFR highly regulated?
    B/c if mean arterial pressure gets too low (such as lots bleeding or lots sweating...ie fluid loss), so does filtration pressure and thus the GFR. Also decrease in MAP increases symp nerve activity, causing arterioles to constrict, which decreases blood flow to glomerulus, which decreases filtration pressure, which decreases GFR
  14. Between what blood pressures can we keep GFR constant?
    80-180 mm Hg
  15. Small increase in ____ causes large increase in fluid filtered and excreted
    GFR (glomular filtration rate)
  16. Selective transport of molecs from inside renal tubules to interstitial fluid, which then move into bloodstream via peritubular capillaries
  17. Just be aware that most solutes with the
    exception of urea are mostly reabsorbed.
  18. During reabsorption, solutes move from inside renal tubules to ____, then to ___.
    interstitial fluid, then into bloodstream via peritubular capillaries
  19. Where does most solute reabsorption occur?
    Proximal convoluted tubule (but some in distal as well)
  20. What are the 2 barriers for reabsorption in kidneys?
    • Epithelial cells of renal tubules
    • Endothelial cells of capillary
  21. What is the difference between active and passive reabsorption?
    • Active: solutes move against their concentration gradient (this causes water to passively move towards the direction of higher solute concentration)
    • Passive: solutes diffuse down their concentration gradient
  22. How does solute reabsorption affect water
    During active solute reabsorption, solutes move against their concentration gradient, and this causes water to passively move towards the direction of higher solute concentration
  23. Point at which a certain plasma concentration of a solute is totally saturated by carrier proteins, and some of it "spillsover" into the urine
    Renal threshold
  24. What does renal threshold mean for a solute
    like glucose that needs a carrier molecule to be reabsorbed?
    It will show up in the urine, such as is the case with a diabetic. Also increases urine volume b/c glucose is considered a solute, and when glucose is in the tubules, water stays there also instead of being reabsorbed.
  25. Where do we have unregulated reabsorption?
    Regulated reabsorption?
    • Unregulated: proximal tubule
    • Regulated: distal tubule/collecting duct
  26. glucose is actively reabsorbed by cotransport of sodium across the ______, followed by facilitated diffusion across the ____
    • Apical membrane
    • Basolateral membrane
  27. What is the loop of Henle’s job?
    Establishes conditions necessary to concentrate urine, which minimizes water loss
  28. When a solute, such as ___ or ___, moves from peritubular capillaries into tubules. Same barriers and transport mechanisms as reabsorption but opposite direction

    K+ or H+
  29. When a solute and water are eliminated from body in form of urine
  30. Amount of a substance excreted =
    Amt filtered + Amt secreted - Amt reabsorbed

  31. Amt of a substance that is excreted depends on: (3)
    • Filtered load
    • Secretion rate
    • Reabsorption rate
  32. If amt of solute excreted per min was less than filtered load --> solute was ____.
    If amt of solute excreted per min was more than filtered load---> solute was ___.
    • Reabsorbed
    • Secreted
  33. Where does urine go from the end of the renal
    Drains into renal pelvis and into ureter, which lead to bladder
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APK Exam4 Ch18
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