Human Physiology

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  1. what are the fuxns of the kidneys
    • make urine
    • regulate osmotic pressure of plasma and other extracellular fluids
    • regulate the excretion of sodium and water
    • regulate the individual concentration of numerous electrolytes
    • regulate plasma bicarbonate concentration
    • eliminate metabolic waste products
    • produce hormones, proteolytic enzymes, paracrines, active D, and glucose
  2. what is the outer part of the kidney
    cortex
  3. what is the inner part of the kidney
    medulla
  4. what is the basic unit of kidney structure and fuxn.
    nephron
  5. Image Upload
    • A - Proximal Convoluted Tubule
    • B - Loop of Henle
    • C - Distal Convoluted Tubule
    • D - Collecting Duct
  6. what are the two types of nephrons
    • cortical
    • juxtamedullary
  7. how do you id a cortical nephron
    loop of Henle is short
  8. how do you id a juxtamedullary nephron
    long loop of henle
  9. what is the ratio of cortical to juxtamedullary in humans
    • 85% cortical
    • 15% juxtamedullary
  10. what are the major structures of a proximal tubular cell
    • microvilli
    • brush border
    • tight junction
    • basolateral cell membrane
    • basement membrane
  11. what
  12. what is the flow of blood through the kidneys
    • artery
    • afferent arterioles
    • glomerulus
    • efferent arteriole
    • peritubular capillaries
    • vein
  13. what is the vasa recta
    capillaries that descend into and ascend from the medulla in parallel with the tubular structrures
  14. where is blood flow/pressure highest in the nephron and why
    glomerulus b/c filtration happens there
  15. where is blood pressure/flow lowest and why
    • peritubular capillaries for uptake of fluid reabsorbed by the tubules
    • maintain higher osmotic pressure
  16. what is the extrinsic mechanism in the kidney vessels
    innervation by SNS releases NE that binds to alpha receptors causing vasoconstriction of the afferent arterioles
  17. how are kidneys regulates without the sympathetic nerve fibers
    intrinsic mechanisms/renal auto regulation
  18. how does renal autoregulation fuxn
    • if BP/flow increases, the afferent arterioles constrict
    • if BP/flow decreases, the afferent arterioles dilate
  19. how does changes in BP/flow affect filtration and excretion
    changes in BP/flow = changes in filtration = big changes in excretion
  20. what can happen if BP/flow remains high
    permanent constriction of afferent arterioles leads to kidney failure
  21. what is the juxtaglomerular apparatus
    structure in the kidneys consisting of macula densa, extraglomerular mesangial cells, and granular cells, located in the region where the distal tubule touches afferent and efferent arterioles of its parent glomerulus
  22. what are granular cells
    cells embedded in the smooth muscle walls of afferent arterioles responsible for synthesizing and releasing renin
  23. where is renin released
    by the granular cells of the juxtaglomerular apparatus
  24. what is the fuxn of renin
    if BP/flow decreases to the kidneys then renin released end result is angiotensin II is formed that stims adrenal cortex to secrete aldosterone
  25. what is the fuxn of aldosterone
    stims Na reabsorption by the collecting ducts
  26. what are macula densa cells
    epithelial cells in the DCT
  27. what are extraglomerular mesangial cells
    messenger cells b/t the granular and macula densa cells
  28. what is the tubuloglomerular feedback
    NaCl composition of tubule fluid in DCT is relayed bact to afferent arterioles, changes in blood flow changes filtration
  29. what is the fuxn of the nephron
    form urine
  30. what are the steps of urine formation
    • glomerular filtration
    • tubular reabsorption
    • tubular secretion
  31. what is glomerular filtration
    • the first step in the formation of urine that is non-selective filtration of plasma
    • allows passage of anything w/ mw <10,000 out of blood into lumen of Bowman's capsule
  32. what is GFR
    the # of ozs. filtered out of blood at given amt. of time
  33. what is tubular reabsorption
    process whereby substances are transferred out of the tubular fluid and returned to the peritubular capillaries; much more selective
  34. where does the bulk of reabsorption occur
    PCT
  35. what is tubular secretion
    mvmt of substances across tubule epithelium in a direction opposite to reabsorption
  36. how much is excreted, filtered, and reabsorbed daily
    • excrete 1.5 -2L/day
    • filter 180 L/day
    • reabsorb 178L/day
  37. what is the fuxn of glomerular filtration
    always takes out of blood into lumen of tubule
  38. what is the glomerular filtration membrane
    three layers capillary endothelium, glomerular basement membrane, podocyte cell layer
  39. what is characteristic of the 1st layer of the glomerular filtration membrane
    fenestrae pores of about 50 -100 nm
  40. what is characteritic of the 2nd layer of the glomerular filtration membrane
    meshwork of fine fibrils embedded in a gel-like matrix
  41. how is the epithelium of the bowman's capsule
    has slit pores
  42. what does all three layers of the glomerular filtration membrane contain and what do they do
    contain glycoproteins that are negatively charged, which repel negative charged plasma proteins
  43. why is the measurement of GFR important
    valuable indication of renal fuxn
  44. what is necessary to measure GFR
    a cmpd that is not secreted or reabsorbed, allows the amt filtered to = amt excreted
  45. what cmpd is meets the requirements for GFR measurement
    inulin
  46. what is inulin
    cmpd form onion/artichoke
  47. what is the formula for clearance
    C = (U * V)/ P
  48. what is renal plasma clearance
    the rate of excretion of a substance divided by its plasma concentration
  49. what are the symbols in C=(U*V)/P
    • u - urine concentration
    • p - plasma concentration
    • v - urine flow rate
  50. what is the urine flow rate
    2ml/ min
  51. what is the clearance rate of inulin
    120ml/min
  52. what are the types of reabsorption
    • active
    • passive
  53. how much water do we excrete a day
    2L/day
  54. what is obligatory water loss
    the amt of we need to excrete a day which is 400ml/day
  55. what is actively reabsorbed
    • glucose
    • Na
    • uric acid
    • phosphate
  56. how is glucose reabsorbed
    • in PCT
    • coupled transport tw/ Na out of lumen
    • into PCT cell out basolateral membrane by facilitated diffusion
  57. how is Na reabsorbed
    • in PCT
    • coupled to glucose, some amino acids, phosphate, Cl, and water
  58. how is uric acid reabsorbed
    in PCT
  59. what causes gout
    high plasma levels of uric acid
  60. what is a symptom of gout
    big toe pain b/c crystal build up in the vessels of that region
  61. what is given to gout patients
    uricosuric agent to lower uric acid levels in plasma by blocking reabsorption of uric acid
  62. what is a uricosuric agent
    Probenecid
  63. what is passively reabsorbed
    • water
    • Cl
    • urea
  64. what is tubular secretion
    out of peritubular capillaries into tubule fluid
  65. why is tubular secretion necessary
    supplements filtration process
  66. what can be secreted
    • organic ion
    • penecillin
  67. what blocks reabsorption and secretion
    probenecid
  68. what is given to patients with penicillin and why
    • probenecid
    • to help patients that don't come back for next shot
    • inhibits peniciliin secretion
  69. what is related to Na reabsorption
    H and K secretion by antiport transport
  70. how is H secreted
    in PCT
  71. what causes acidified urine
    H in urine
  72. where is potassium secreted
    early in collecting ducts
  73. how is potassium secreted
    assoc. w/ Na/K ATPase pump
  74. what cmpd is necessary to measure total renal plasma flow
    PAH
  75. what happens to PAH
    almost completely cleared from the blood in 1 pass thru
  76. what is the total renal plasma flow rate
    625 ml/min
  77. why is Na reabsorption in the kidney important
    • Na reabsorption causes water reabsorption
    • Na reabsorption coupled to reabsorption of organic and inorganic ions
    • Na reabsorption related to secretion of H and K
    • 80% of energy supports Na reabsorption
  78. where is 70% of water and Na reabsorbed
    PCT
  79. how is Na reabsorbed in the PCT
    • enters lumen by Na/solute cotransporters
    • exits by basolateral Na/K ATPase pumps
  80. what drives Na into the blood
    peritubular capillary Starling forces
  81. how does peritubular capillary starling forces fuxn
    tubules pressure is low do to the blood passing thru other vessels, favors the uptake of Na
  82. how much Na and water is reabsorbed in the Loop of Henle
    20% of Na and 10% of water
  83. why is less water reabsorbed in the loop of henle
    the ascending loop is impermeable to water
  84. how is Na reabsorbed in the loop of henle
    • reabsorption occurs through coupled transport of Na/K/Cl
    • exits by Na/K ATPase pump from the basolateral membrane
  85. why is less Na reabsorbed in the DCT and collecting ducts
    b/c of tight epithelial
  86. how much Na and water is reabsorbed in the DCT and collecting ducts
    9% of Na and 19% of water
  87. what controls the collecting ducts
    hormones
  88. what hormone stims Na reabsorption in the collecting duct
    aldosterone
  89. what is the reabsorption of Na in the collecting duct linked to
    Na/K exchanger
  90. what is the fuxn of ADH
    increase collecting duct permeability, causes more water reabsorption
  91. how does the lack of ADH affect Diabetes insipidus patients
    • less water reabsorbed causing freguent urination
    • 15-20L/day = polyuria
  92. what does the bowman's capsule surround
    glomerulus
  93. what causes the activation renal autoregulation
    BP/flow increases
  94. what refers to the rate of excretion of a substance divided by its plasma concentration
    renal plasma clearances
  95. where does active of absorption of Na occur
    PCT
  96. what does aldosterone and ADH act to increase
    reabsorption of Na and water
  97. secretion

    a. dependent upon Na/K ATPase pump
    b. requires both the descending and ascending limbs
    c. K is controlled by this process
    d. urea shows this
    e. is decreased with low MAP
    K is controlled by this process
  98. active reabsorption

    a. dependent upon Na/K ATPase pump
    b. requires both the descending and ascending limbs
    c. K is controlled by this process
    d. urea shows this
    e. is decreased with low MAP
    dependent upon Na/K ATPase pump
  99. countercurrent multiplication

    a. dependent upon Na/K ATPase pump
    b. requires both the descending and ascending limbs
    c. K is controlled by this process
    d. urea shows this
    e. is decreased with low MAP
    requires both ascending and descending limbs
  100. filtration

    a. dependent upon Na/K ATPase pump
    b. requires both the descending and ascending limbs
    c. K is controlled by this process
    d. urea shows this
    e. is decreased with low MAP
    is decreased with low MAP
  101. passive reabsorption

    a. dependent upon Na/K ATPase pump
    b. requires both the descending and ascending limbs
    c. K is controlled by this process
    d. urea shows this
    e. is decreased with low MAP
    urea show this
  102. principal

    a. releases renin
    b. has microvilli
    c. responds to ADH
    d. has fenestrae
    e. has foot processes
    responds to ADH
  103. tubular epithelial

    a. releases renin
    b. has microvilli
    c. responds to ADH
    d. has fenestrae
    e. has foot processes
    has microvilli
  104. glomerular capillary

    a. releases renin
    b. has microvilli
    c. responds to ADH
    d. has fenestrae
    e. has foot processes
    has fenestrae
  105. granular

    a. releases renin
    b. has microvilli
    c. responds to ADH
    d. has fenestrae
    e. has foot processes
    releases renin
  106. podocyte

    a. releases renin
    b. has microvilli
    c. responds to ADH
    d. has fenestrae
    e. has foot processes
    has foot processes
  107. how much body water is contained in the ECF and ICF
    • ECF - 1/3 of body water
    • ICF - 2/3 of body water
  108. what determines water distribution
    osmotic pressure
  109. what is the largest contributor to osmotic pressure of body fluids
    electrolytes
  110. what is osmotic pressure directly related to
    osmolality
  111. what is osmolality
    total solute conc.
  112. what is directly related to the amt of water in a compartment
    the amt of solute in that compartment
  113. what happens if solute conc. increases
    osmolality increases
  114. how does water move
    • water moves from lower osmolality to higher osmolality
    • water moves from lower osmotic pressure to higher OP
  115. what is equal in humans
    the OP of ECF and ICF
  116. what determines the volume of water in the ECF
    Na and its accompanying anions accounts for 90%
  117. what determines the volume of water in ICF
    K
  118. what do kidneys have a major role in
    balancing water, electrolytes, protons, and some organic cmpds.
  119. what are the 2 mechanisms of water balance
    hormonal and thirst
  120. how does hormonal water balance work
    ADH controls renal excretion of water
  121. how does the thirst mechanism of water balance work
    • osmoreceptors in the hypothalamus detect cellular hydration
    • signal cerebral cortex
    • you feel thirsty
  122. what may also stim thirst
    • blood vol receptors in CV system and kidneys
    • causes hypovolemia and
    • you fell thirsty
  123. what is responsible for 95% of total Na output
    urine
  124. what is closely related to Na balance
    ECF
  125. what controls Na excretion
    negative feedback system
  126. what mechanisms responds to changes in ECF vol
    • GFR
    • plasma aldosterone levels
    • renal SNS activity
    • Plasma ANP
    • peritubular capillary starling forces
    • intrarenal blood flow distribution
  127. how does GFR respond to changes in ECF vol
    increase of ECF <increase of GFR < increase in sodium excretion
  128. how does aldosterone react to changes in ECF vol
    decrease ECF vol <renin release<leads to angiotensin II< aldosterone< Na reabsorption
  129. how does ECF vol affect renal sns activity
    decrease of renal sodium excretion
  130. how does ECF vol affect ANP
    increase Na excretion
  131. how does ECF vol affect peritubular capillary starling forces
    increase Na excretion with increase in hydrostatic pressure or decrease of colloid osmotic pressure
  132. how does ECF vol affect intrarenal blood flow

Card Set Information

Author:
hillab@warhawks.ulm.edu
ID:
15262
Filename:
Human Physiology
Updated:
2010-04-21 01:43:16
Tags:
biology kidney physiology
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Description:
test 3
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