Urinary- Tubular Reabsorption

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Urinary- Tubular Reabsorption
2015-09-08 20:11:13
vetmed urinary tubules

vetmed urinary system
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  1. How much urine should the kidneys make?
    the min amount of water needed to excrete the normal metabolic by-products and maintain homeostasis
  2. Because the medulla becomes more _______ the deeper you go, the juxtamedullary nephrons contribute more to creating _________ urine.
    concentrated; concentrated
  3. Function of the glomerulus.
    sieve- water and dissolved solutes leave capillary and enter bowman's space
  4. Function of the proximal tubule.
    bulk reabsorption of Na+, Cl-, glucose, calsium, AAs, and water
  5. Function of the descending thin limb of the loop of henle.
    water reabsorption
  6. Function of the ascending thick limb of the loop of henle.
    sodium reabsorption
  7. Function of the distal tubule.
    diluting segment, fine-tunes acid-base balance and potassium balance
  8. Function of the collecting duct.
    final determination of urine concentration via aquaporins and ADH
  9. Reabsorption that involves entering the tubular epithelial cell from the luminal side and then exiting via the basolateral side.
    transcellular reabsorption
  10. Reabsorption that involves solutes moving between the cells leaky tight junctions, such as in the proximal tubule.
    paracellular reabsorption
  11. Reabsorption is driven by...
    energy-consuming pumps and electrochemical and conc gradients
  12. Transcellular reabsorption requires...
    a way to pass the cellular membrane (fat soluble, carrier protein)
  13. Type of active transport directly coupled to an energy source, which is used to move solutes against their electrochemical gradient.
    primary active transport
  14. Type of active transport that uses the electrochemical gradient generated by primary active transport.
    secondary active transport
  15. Primary active transport of sodium via _________ decreases the _________ sodium content, creating a favorable gradient for sodium to move from _______ to _______; coupling sodium and ________ to a carrier molecule to carry the latter against its conc gradient is an example of secondary active transport.
    Na+K+ATPase pump; intracellular; lumen; inside the cell; glucose
  16. Type of passive transport in which molecules move down their conc gradient.
    simple diffusion
  17. Type of passive transport that requires a carrier molecule for the molecule to pass down its electrochemical gradient.
    facilitated diffusion
  18. Type of passive transport that involves the osmosis of water carrying small solutes with it.
    osmosis and solvent drag
  19. Pinocytosis is a form of ________; it occurs in the ________ to clear _______ that was not filtered at the glomerulus.
    active transport; proximal tubule; protein
  20. Substances that are __________ have a theoretical transport maximum.
    reabsorbed via a carrier molecule
  21. The limit to the rate at which a substance can be reabsorbed before all the nephrons start spilling it into the urine.
    transport maximum
  22. Low levels of a substance that may start to appear in the urine before the transport maximum is reached; due to the fact that some nephrons are not as efficient as others.
    transport threshold
  23. There is no transport maximum for substances that are __________.
    passively reabsorbed without a carrier
  24. For a substance that is passively reabsorbed without a carrier, no matter how high blood concs are,...
    it will all be reabsorbed because it has no transport maximum.
  25. The rate of transport for substances that are passively reabsorbed without a carrier is determined by... (3)
    electrochemical gradient, permeability of the membrane, time the fluid is in the tubule
  26. What two parts of the nephron have the highest metabolic activity? What is a possible repercussion of this?
    proximal tubule and ascending thick limb of the loop of henle; prone to damage during ischemia
  27. The Na+K+ATPase pump moves ________ out of the cell and ________ in the cell to create a relative ________ in the cell, allowing for its subsequent reabsorption.
    3 Na+; 2K+; sodium deficit
  28. The vast majority of sodium is reabsorbed to prevent _________.
    hypovolemic collapse
  29. The bulk of filtered sodium is reabsorbed in the _________ with ________ in the first half of the tubule and with ________ in the second half.
    proximal tubule; glucose; chloride
  30. Glucose is freely filtered at the __________; it is reabsorbed in the _________ via ___________ with sodium; it moves across the basolateral membrane back into the blood by _________.
    glomerulus; proximal tubule; secondary active transport; facilitated diffusion
  31. Glucose requires a __________ an therefore has a _________.
    carrier molecule; transport maximum
  32. Amino acids are reabsorbed in the ________ via ___________ coupled with ____________.
    proximal tubule; secondary active transport; sodium reabsorption
  33. Filtered urea is _________ reabsorbed in the ___________; as water is reabsorbed, urea conc increases, creating a favorable gradient for reabsorption; urea is also passively reabsorbed through ________ in the _____________ and ___________.
    passively; proximal tubule; urea transports; ascending thin loop of henle; medullary collecting ducts
  34. Chloride is passively reabsorbed via the __________ pathway or though __________ in the ____________.
    paracellular; secondary active transport with sodium; proximal tubule
  35. The descending thin limb of the loop of henle is highly permeable to _________, which is passively reabsorbed.
  36. The ascending thin limb of the loop of henle is _________ to water.
  37. The ascending thick limb of the loop of henle reabsorbs __(3)__ by using the __________ and __________.
    filtered sodium, chloride, and potassium; Na+K+Cl- pump; secondary active transport
  38. Furosemide affects the ___________ to have a _________ effect.
    Na+K+Cl- pump; diuretic (theses substances are not reabsorbed, so water is pulled back into the ultrafiltrate in the collecting duct)
  39. Describe the function of the distal tubule.
    first portion similar to ascending thick limb of the loop of henle (filter sodium, chloride, potassium); second portion similar to collecting duct
  40. The macula densa is the specialized segment of the _________ that makes up part of the juxtaglomerular apparatus.
    distal tubule
  41. The early distal tubule is sometimes called the _________ because there is some reabsorption of _________ here.
    diluting segment; filtered sodium
  42. The principal cells of the _______ resorb _________ and secrete _________ under the influence of __________.
    cortical collecting duct; sodium; potassium; aldosterone
  43. How does aldosterone affect the collecting duct?
    it causes transcription of proteins that increase the activity of the Na+K+ATPase pump and opens luminal K+ pumps (resorb sodium, secrete K+); it also increases the number of open sodium channels
  44. Intercalated type A cells in the __________ secrete ________ and return ________ to systemic circulation.
    collecting duct; acid; bicarb
  45. Intercalated type B cells in the __________ secrete ___________.
    collecting duct; bicarb/alkali
  46. Carnivores need more ___________ in their collecting ducts to secrete _________.
    intercalated type A cells; acid
  47. Herbivores need more ____________ in their collecting ducts to secrete __________.
    intercalated type B cells; alkali
  48. The majority of water reabsorption occurs in the _______; some occurs in the __________; a small amount occurs in the ________.
    proximal tubule; descending thin limb of the loop of henle; collecting duct
  49. What parts of the nephron are impermeable to water?
    ascending thick limb of the loop of henle, early distal tubule (shares properties with aforementioned)
  50. What is the prime directive of PTH?
    increase calcium
  51. If blood calcium decreases, _______ is stimulated and increases blood calcium through __(3)__ target organs.
    PTH; bone, gut, and kidney
  52. PTH increases ________ to mobilize calcium; it also increases _________ formation, which increases calcium absorption from the gut; finally, it increases renal reabsorption of calcium in the __(2)__.
    bone resorption; Vit D; loop of henle and distal tubule
  53. Most calcium reabsorption occurs in the _________.
    proximal tubule
  54. PTH increases calcium reabsorption in... (2)
    loop of henle and distal tubule
  55. __________ calcium reabsorption in independent of PTH.
    Proximal tubule
  56. Most calcium reabsorption in the proximal tubule occurs __________ via _________ as _________.
    paracellularly; solvent drag; water is reabsorbed
  57. What are the mechanisms of calcium reabsorption in the proximal tubule? (4)
    paracellular via solvent drag, transcellular via Na+K+ATPase creates gradient for luminal Ca++ channels, Ca++ATPase pump, 3Na+Ca++ countertransporter
  58. What are the mechanisms of calcium reabsorption in the ascending thick loop of henle? (2)
    paracellular, transcellular stimulated by PTH
  59. What are the mechanisms of calcium reabsorption in the distal tubule? (3)
    luminal calcium channel, basolateral Ca++ATPase pump, 3Na+Ca++ countertransporter
  60. In the distal tubule, PTH increases...
    the number of 3Na+Ca++ countertransporters--> net calcium reabsorption
  61. With a high amount of filtered phosphate (hyperphosphatemia), __________ is reached, leading to...
    transport maximum; excretion of excess phosphate in urine.
  62. With a low amount of filtered phosphate (hypophosphatemia), ...
    all phosphate is reabsored.
  63. PTH _______ the transport maximum of phosphate, causing the kidneys to...
    decreases; dump more phosphate in the urine.
  64. The main site for phosphorous reabsorption is the _________, which has a __________ that reabsorbs ______ with each phosphate.
    proximal tubule; Na+Ph co-transporter; 3Na+
  65. Most of the magnesium reabsorption takes place in the ________ by a __________ route through a __________.
    Loop of Henle; paracellular; divalent ion pole
  66. The percentage of glomerular filtrate that gets reabsorbed in the proximal tubule remains constant at _____.
  67. An increase in systemic arterial pressure increases... (2)
    renal sodium and water excretion.
  68. Aldosterone functions. (2)
    increases sodium reabsorption and potassium excretion
  69. Angiotensin II functions. (2)
    increases sodium and water reabsorption
  70. ADH function. (1)
    increase water reabsorption
  71. Atrial natriuretic peptide (ANP) functions. (2)
    decreases sodium and water reabsorption
  72. PTH functions. (2)
    increase sodium reabsorption and potassium excretion
  73. The sympathetic nervous system _________ afferent and efferent arterioles, _________ water and sodium excretion; also, stimulates _______ release.
    constricts; decreasing; renin
  74. Hydrostatic pressure in the peritubular capillary opposes __________.
  75. Colloid osmotic pressure in the peritubular capillary favors __________.
  76. In the peritubular capillary, hydrostatic pressure is influenced by... (2)
    arterial pressure, resistances of afferent and efferent arterioles
  77. Peritubular capillary colloid osmotic pressure is determined by... (2)
    systemic plasma colloid osmotic pressure, filtration fraction
  78. A higher filtration fraction means more _________ being ________, leading to...
    water; filtered in the glomerulus; increased protein conc left in plasma.
  79. Once solutes leave the lumen and enter the renal interstitium, they can be...
    taken up by peritubular capillary and washed away.
  80. If reabsorption in the peritubular capillary is low due to high _________ or low _________, solutes in the renal interstitium are more likely to...
    hydrostatic pressure; oncotic pressure; diffuse back into the tubular lumen.