a&p test 5

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  1. Regulation of Water Output: Influence of ADH
    • Decrease in ADH leads to - dilute urine and decrease volume of body fluids
    • Increase in ADH leads to concentrated urine
  2. Dehydration
    Negative fluid balance
  3. ECF water loss due to
    hemorrhage, severe burns, prolonged vomiting or diarrhea, profuse sweating, water deprivation, diuretic abuse
  4. Dehydration Signs and symptoms
    thirst, dry flushed skin, oliguria (low output of urine)
  5. Dehydration may lead to what conditions
    weight loss, fever, mental confusion, hypovolemic shock, and loss of electrolytes
  6. Define Hypovolemic shock
    An emergency condition in which severe blood and fluid loss makes the heart unable to pump enough blood to the body. This type of shock can cause many organs to stop working
  7. Mechanism of dehydration
    Excessive loss of H2O from ECF leads to ECF osmotic pressure rising leads to Cells loosing H2O to ECF by osmosis and cells shrink
  8. Edema
    Atypical accumulation of IF fluid leads to tissue swelling
  9. Edema causes
    Due to anything that increases flow of fluid out of the blood or hinders its return
  10. edema can be caused by
    • Increase in Blood pressure
    • Increased Capillary permeability (usually due to inflammatory chemicals)
    • —Incompetent venous valves
    • —Localized blood vessel blockage
    • Increased blood volume
  11. Edema
    • Hindered fluid return occurs with an imbalance in colloid osmotic pressures, e.g., hypoproteinemia (decreased plasma proteins)
    • Fluids fail to return at the venous ends of capillary beds
    • —Results from protein malnutrition, liver disease, or glomerulonephritis
  12. Edema
    Blocked (or surgically removed) lymph vessels
    • —Cause leaked proteins to accumulate in IF
    • Increased Colloid osmotic pressure of IF draws fluid from the blood
    • Results in low blood pressure and severely impaired circulation
  13. What are Electrolytes
    salts, acids, and bases
  14. Electrolyte balance usually refers only to ?
    salt balance
  15. Importance of saltsb (3)
    • Controlling fluid movements
    • —Excitability
    • Membrane permeability
  16. Central Role of Sodium
    • Changes in plasma sodium levels affect
    • Plasma volume, blood pressure
    • ICF and IF volumes
    • No receptors are known that monitor Na+ levels in body fluids
    • Na+-water balance is linked to blood pressure and blood volume control mechanisms
  17. Define Hypernatremia
    elevated plasma Na+
  18. Define Hyponatremia:
    decreased plasma Na+
  19. Aldosterone
    • Na+ reabsorption
    • —65% is reabsorbed in the proximal convoluted tubule (PCT)
    • —25% is reclaimed in the loop of Henle
    • Aldosterone Leads to active reabsorption of remaining Na+
    • Water follows Na+ if ADH is present
  20. What is the main trigger for for aldosterone release?
    Renin-angiotensin mechanism
  21. Mechanism for production of aldosterone
    • Juxtaglomerular apparatus in kidney secretes renin in response to due to decrease in blood pressure
    • Renin catalyzes the production of angiotensin II, which prompts aldosterone release
  22. —Atrial natriuretic hormone (ANH) are released by which cells in which organ?
    what are they released in response to?
    • Atrial cells in the heart
    • in response to stretch (increased blood pressure)
  23. Effects of Atrial natriuretic hormone (ANH)
    • —Decreases blood pressure and blood volume:
    • decreases ADH, renin and aldosterone production —­
    • Increases Excretion of Na+ and water
    • —Promotes vasodilation directly and also by decreasing production of angiotensin II
  24. Influence of Estrogen
    • Estrogen: ­ Increases NaCl reabsorption (like aldosterone)
    • leads to H2O retention during menstrual cycles and pregnancy
  25. —Importance of potassium:
    Affects resting membrane potential (RMP) in neurons and muscle cells (especially cardiac muscle)
  26. Define Hyperkalemia
    abnormally high levels of potassium in extracellular fluid
  27. Define Hypokalemia
    abnormally low levels of potassium in extracellular fluid.
  28. Regulation of Potassium Balance
    • —H+ shift in and out of cells
    • Leads to corresponding shifts in K+ in the opposite direction to maintain cation balance
    • Interferes with activity of excitable cells
  29. Influence of aldosterone on Regulation of Potassium Balance
    • Stimulates K+ secretion (and Na+ reabsorption) by cells in the kidney tubules
    • Increased K+ in the adrenal cortex causes:
    • —Release of aldosterone
    • Potassium secretion
  30. Regulation of Calcium
    —What is Ca2+ in ECF important for?
    • Neuromuscular excitability
    • Blood clotting
    • Cell membrane permeability
    • Secretory activities
  31. Define Hypocalcemia-
    decreased calcium in the blood
  32. Define Hypercalcemia -
    Increased calcium in the blood
  33. What are the largest reservoir for Ca2+ and phosphates
  34. What stimulates Ca2+ uptake in the intestines
    Vitamin D
  35. What affect does Calcitonin have on extracellular Ca2+ levels
  36. Parathyroid hormone (PTH) increases or decreases Ca2+ extracellular levels
  37. true or False
    Calcium reabsorption and phosphate excretion go hand in hand
  38. Regulation of Phosphate Ions
    • Under normal conditions, reabsorption of phosphate occurs at maximum rate in the nephron
    • An increase in plasma phosphate increases amount of phosphate in nephron beyond that which can be reabsorbed; excess is lost in urine
  39. Define Hypophosphatemia
    reduced absorption from intestine due to vitamin D deficiency or alcohol abuse.
  40. Define Hyperphosphatemia
    renal failure, hyperparathyroidism (secondary to elevated plasma calcium levels)
  41. Regulation of Chloride Ions
    • Cl– is the major anion in the ECF
    • Helps maintain the osmotic pressure of the blood
    • 99% of Cl– is reabsorbed under normal pH conditions
    • When acidosis occurs, fewer chloride ions are reabsorbed
  42. Acid-Base Balance
    pH affects all functional proteins and biochemical reactions
  43. —Normal pH of body fluids
    Arterial blood:
    Venous blood and IF fluid:
    • Arterial blood: pH 7.4
    • Venous blood and IF fluid: pH 7.35
    • —ICF: pH 7.0
  44. Define Alkalosis
    arterial blood pH >7.45
  45. define Acidosis
    arterial blood pH < 7.35
  46. Acid-Base Balance

    What is most H+ produced by
  47. H+ is also produced by (4)
    • Phosphoric acid from breakdown of phosphorus-containing proteins in ECF
    • Lactic acid from anaerobic respiration of glucose
    • Fatty acids and ketone bodies from fat metabolism
    • —H+ liberated when CO2 is converted to HCO3– in
    • blood
  48. Concentration of hydrogen ions is regulated sequentially by
    • Chemical buffer systems: rapid; first line of defense
    • Brain stem respiratory centers: act within 1–3 min
    • —Renal mechanisms: most potent, but require hours to days to effect pH changes
  49. 1 Strong acids _______ in water; can _____ affect pH
    2 Weak acids dissociate _____ in water; are _____ at preventing pH changes
    3 _____ dissociate easily in water; quickly tie up H+
    —4 Weak bases accept H+ _______
    5 Buffers: Resist changes in pH —When H+ added, buffer _______
    6 When H+ removed, buffer ______
    • 1 Dissociate Completely, dramatically
    • 2 partially, efficient
    • 3 Strong bases
    • 4 more slowly
    • 5 removes it
    • 6 replaces it
  50. Define Chemical buffer system
    system of one or more compounds that act to resist pH changes when strong acid or base is added
  51. what are the 3 buffer systems
    • Bicarbonate buffer system
    • Phosphate buffer system
    • Protein buffer system
  52. Bicarbonate Buffer System
    • Mixture of H2CO3 (carbonic acid: weak acid) and HCO3– (bicarbonate ion: a weak base)
    • Buffers ICF and ECF
    • The only important ECF buffer
  53. Bicarbonate Buffer System
    If strong acid is added:
    • HCO3– ties up H+ and forms H2CO3
    • HCl + HCO3– ® H2CO3 + Cl –
    • pH decreases only slightly, unless all available HCO3–
    • (alkaline reserve) is used up
    • HCO3– concentration is closely regulated by the kidneys
  54. Bicarbonate Buffer System
    If strong base is added
    • It causes H2CO3 to dissociate and donate —H+
    • H+ ties up the base (e.g. OH–)
    • NaOH + H2CO3 Leads to NaHCO3 + H2O
    • pH rises only slightly
    • H2CO3 supply is almost limitless (from CO2 released by respiration) and is subject to respiratory controls
  55. Phosphate Buffer System
    • Action is nearly identical to the bicarbonate buffer
    • Components are sodium salts of:
    • Dihydrogen phosphate (H2PO4–), a weak acid
    • Donates a free H+ when H+ concentration falls
    • —Monohydrogen phosphate (HPO42–), a weak base
    • —Accepts a free H+ when H+concentration rises
    • Effective buffer in urine and ICF, where phosphate concentrations are high
  56. Protein Buffer System
    Intracellular proteins are the most plentiful and powerful buffers; plasma proteins are also important

    • —Protein molecules are amphoteric (can function as both a weak acid and a weak base)
    • When pH rises, organic acid or carboxyl (COOH) groups release H+
    • When pH falls, NH2 groups bind H+
  57. Physiological Buffer Systems
    • —Respiratory and renal systems
    • Act more slowly than chemical buffer systems
    • Have more capacity than chemical buffer systems
  58. Respiratory Regulation of H+
    • Respiratory system eliminates CO2
    • A reversible equilibrium exists in the blood:
    • CO2 + H2O <---> H2CO3 <---> H+ + HCO3–
    • During CO2 unloading the reaction shifts to the left (and H+ is incorporated into H2O)
    • During CO2 loading the reaction shifts to the right (and H+ is buffered by proteins)
  59. Respiratory Regulation of H+
    • activates medullary chemoreceptors
    • —Rising plasma H+ activates peripheral chemoreceptors
    • As carbon dioxide levels increase ---> pH decreases ----> respiratory rate increases -----> H+ concentration decreases
  60. Respiratory Regulation of H+
    • depresses the respiratory center
    • —As carbon dioxide levels decrease ----> pH increases -----> respiratory rate and depth decrease ------> H+ concentration increases
  61. Respiratory Regulation of H+
    What do respiratory system impairments cause?
    —Respiratory system impairment causes acid-base imbalances
  62. Hypoventilation leads to
    increases blood carbon dioxide levels ® respiratory acidosis
  63. Hyperventilation leads to
    decreases blood carbon dioxide levels ® respiratory alkalosis
  64. Acid-Base Balance
    • Chemical buffers cannot eliminate excess acids or bases from the body
    • —Lungs eliminate volatile carbonic acid by eliminating CO2
    • Kidneys eliminate other fixed metabolic acids (phosphoric, uric, and lactic acids and ketones) and prevent metabolic acidosis
  65. Renal Mechanisms of Acid-Base Balance
    • Most important renal mechanisms
    • Conserving (reabsorbing) or generating new HCO3–
    • Excreting HCO3–
    • Renal regulation of acid-base balance depends on secretion of H+
  66. Acidosis: pH body fluids below _____
  67. Respiratory Acidosis
    • Most common cause of acid-base imbalances
    • —Due to decrease in ventilation or gas exchange
    • Characterized by falling blood pH and rising blood CO2
    • levels
  68. Metabolic Acidosis
    • A decrease in pH not caused by abnormal blood CO2 levels
    • Ingestion of too much alcohol (----> acetic acid)
    • —Excessive loss of HCO3– (e.g., persistent diarrhea) —Accumulation of lactic acid, ketosis in diabetic crisis, starvation, and kidney failure
  69. Alkalosis: pH body fluids above ______
  70. Respiratory Alkalosis
    —A common result of hyperventilation due to stress or pain
  71. Metabolic Alkalosis
    • Metabolic alkalosis is much less common than metabolic acidosis
    • An increase in pH not caused by abnormal blood CO2 levels
    • —Indicated by rising blood pH and HCO3–
    • Caused by vomiting of the acid contents of the stomach or by intake of excess base (e.g., antacids, bicarbonate from soda)
Card Set:
a&p test 5
2012-03-25 00:50:51

maria college a&p test 5
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