Human Physiology 14

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NursyDaisy
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100707
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Human Physiology 14
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2011-10-11 23:50:08
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Human Physiology
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Cardiac Output, Blood Flow, and B/P
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  1. What is the volume of blood pumped per minute by each ventricle?
    cardiac output
  2. What is the volume of blood pumped per beat by each ventricle?
    stroke volume
  3. What is the beats per minute of the heart?
    cardiac rate
  4. What is the stroke volume times the cardiac rate?
    cardiac output
  5. What is the average blood volume of an adult?
    5.5 L
  6. What is the effect of epinephrine on cardiac rate?
    an increase
  7. What is the effect of norepinephrine on cardiac rate?
    an increase
  8. What is the effect of acetylcholine on cardiac rate?
    a decrease
  9. What coordinates the activity of the autonomic innervation of the heart?
    the cardiac control center of the medulla oblongata
  10. What is the general effect of the sympathetic division of the ANS on the heart?
    It increases the rate and the strength of contractions.
  11. What is the general effect of the parasympathetic division of the ANS on the heart?
    It decreases the rate of contraction.
  12. What three factors regulate the stroke volume?
    • end-diastolic volume
    • total peripheral resistance
    • the strength of the ventricular contraction
  13. What term refers to the proportion of end-diastolic volume that is ejected?
    ejection fraction
  14. What is the approximate ejection fraction (%) of the heart?
    60%
  15. What physiological law states the relationship between EDV, contraction strength, and stroke volume?
    the Frank-Starling Law
  16. According to the Frank-Starling Law an increase in what physiological factor will increase the strength of ventricular contraction?
    end-diastolic volume
  17. An increase in the end-diastolic volume changes what factor within the myocardial cells and thus
    increases the force of the contraction?
    sacromere length
  18. How does an increase in sarcomere length increase the strength of the contraction of myocardial cells?
    At rest actin filaments overlap one another. As length increase actin and myosin overlap optimally.
  19. How does the Frank-Starling Law explain how the heart can adjust to a rise in total peripheral resistance?
    • a rise in peripheral resistance decreases stroke volume thus increasing EDV resulting in further
    • stretching the ventricle and increasing the strength of the contraction
  20. Approximately what portion of the total blood volume is contained in the veins?
    two-thirds
  21. What is the mean venous pressure?
    2 mm HG
  22. What is the mean arterial pressure?
    100 mm Hg
  23. What factors move blood through veins?
    • skeletal muscle pump, pressure differences between thoracic cavity and the abdominal cavity
    • sympathetic nerve activity
    • gravity
  24. What proportion of the bodyís water is held in the intracellular compartment?
    two-thirds
  25. What proportion of the bodyís water is held in the extracellular compartment?
    one-third
  26. What percentage of the extracellular fluid interstitial fluid?
    80%
  27. What percentage of the extracellular fluid is held in the blood?
    20%
  28. What are the opposing forcing in filtration and absorption in the capillaries?
    hydrostatic pressure in the capillary and interstitial fluid and colloid osmotic pressure in the blood and interstitial fluid
  29. What causes net filtration at the arterial end of a capillary?
    high hydrostatic pressure within the capillary
  30. What causes net absorption at the venous end of a capillary?
    high osmotic pressure in the blood
  31. What maintains the osmotic pressure of blood?
    plasma proteins (albumins)
  32. What term refers to an excessive accumulation of tissue fluid?
    edema
  33. What are six possible causes of edema?
    • high arterial B/P
    • venous obstruction
    • leakage of plasma proteins into the interstitial fluid
    • myxedema
    • decreased plasma protein concentration
    • obstruction of lymphatic drainage
  34. What hormone is released by the posterior pituitary in response to an increase in the osmolality of the blood?
    antidiuretic hormone
  35. What two factors can increase the osmolality of the blood?
    • dehydration
    • excessive salt intake
  36. What hormone is produced by the atria of the heart in response to an increase in blood volume?
    atrial natriuretic peptide
  37. What steroid hormone is secreted by the adrenal cortex in response to a decrease in blood volume and stimulates the reabsorption of salt by the kidneys?
    aldosterone
  38. What structures in the kidneys sense a decrease in blood volume?
    juxtaglomerular apparatuses
  39. What enzyme is released by the juxtaglomerular apparatus in response to low blood pressure?
    renin
  40. What is the action of the enzyme renin?
    It cleaves angiotensin I from angiotensinogen
  41. What is the role of angiotensin I?
    It is converted to angiotensin II.
  42. How is angiotensin I converted to angiotensin II?
    Angiotensin-converting enzyme (ACE) does it in the lungs.
  43. What is the action of angiotensin II?
    Vasoconstriction and the release of aldosterone
  44. What endocrine gland secretes aldosterone?
    the adrenal cortex
  45. What is the effect of aldosterone?
    increased uptake of Na+ and water in the kidneys
  46. What is the action of atrial natriuretic hormone?
    • decrease release of ADH
    • increased NaCl and water excretion in the kidneys
  47. What two factors decrease blood flow (increase resistance) as they increase?
    length of the vessel and viscosity of the blood
  48. What factor increases the flow of blood (decreases resistance) as it increases?
    the radius of the vessel
  49. How does blood flow to an organ change if the arteries supplying it vasodilate?
    It increases
  50. How does blood flow to an organ change if the arteries supplying it vasoconstrict?
    It decreases
  51. What effect do adrenergic sympathetic fibers have on vascular smooth muscle?
    vasoconstriction
  52. What effect do cholinergic sympathetic fibers have on vascular smooth muscle?
    vasodilation
  53. The blood vessels of what organs are innervated by adrenergic sympathetic fibers?
    digestive organs, kidneys, skin
  54. The blood vessels of what organs are innervated by cholinergic sympathetic fibers?
    skeletal muscles
  55. In relation to the neurotransmitter released, parasympathetic fibers are always what type?
    cholinergic
  56. Parasympathetic fibers always have what effect on the blood vessels they innervate?
    vasodilation
  57. Parasympathetic innervation of blood vessels is limited to what organs?
    • the digestive tract
    • external genitalia
    • salivary glands
  58. What are molecules produced by one tissue to help regulate another tissue of the same organ?
    paracrine regulators
  59. What is the effect of nitric oxide, bradykinin, and prostacyclin on smooth muscle? What effect
    would this have on blood vessels?
    relaxation & vasodilation
  60. What is the effect of the paracrine regulator endothelin-1?
    vasoconstriction
  61. If blood pressure and blood flow into an organ are too low, what is the response of the arteries supplying that organ?
    vasodilation
  62. If blood pressure into an organ is too high, what is the response of that organ?
    vasoconstriction
  63. What type of control mechanism results from the direct response of vascular smooth muscle to changes in blood pressure?
    myogenic
  64. What type of control mechanism brings about changes in blood flow in response to changes in the
    chemical environment of an organ?
    metabolic
  65. List four chemical changes that promote vasodilation.
    • decreased oxygen concentration
    • increased CO2 concentration
    • decreased pH
    • release of adenosine or K+
  66. What type of metabolism does the myocardium use?
    aerobic
  67. List three adaptations the myocardium uses to maintain its aerobic metabolism.
    • dense capillary beds
    • myoglobin
    • high numbers of mitochondria
  68. What is the effect of norepinephrine on alpha-adrenergic receptors in blood vessels of the heart?
    vasoconstriction
  69. What is the effect of epinephrine on beta-adrenergic receptors of the blood vessels of the heart?
    vasodilation
  70. Vasodilation of the blood vessels of the heart results from what type of regulatory mechanism?
    intrinsic metabolic
  71. What effect results from sympathetic adrenergic fibers stimulating alpha-adrenergic receptors of blood vessels of skeletal muscle?
    vasoconstriction
  72. What effect results from sympathetic cholinergic fibers stimulating beta-adrenergic receptors of blood vessels in skeletal muscles?
    vasodilation
  73. What effect results epinephrine stimulating beta- adrenergic receptors of blood vessels of skeletal
    muscle?
    vasodilation
  74. What type of control mechanism increases blood flow into skeletal muscles during prolonged exercise?
    intrinsic metabolic
  75. What three changes increase the blood flow to skeletal muscles during exercise?
    • increased cardiac output
    • metabolic vasodilation in the exercising muscles
    • the diversion of blood away from the viscera and skin
  76. What factors increase cardiac output during exercise?
    • increased cardiac rate
    • maintenance of EDV due to increased venous return resulting from increased skeletal muscle activity and increased respiration
    • increased ejection fraction
  77. What are the responses of blood vessels within the brain to increases and decreases of B/P?
    • Increased B/P leads to vasoconstriction
    • Decreased B/P leads to vasodilation
  78. What type of regulatory mechanism leads to changes in the blood vessels of the brain as B/P increases and decreases?
    intrinsic myogenic
  79. What changes occur in blood vessels in the brain as CO2 levels increase or decrease?
    • Increases cause vasodilation
    • Decreases lead to vasoconstriction
  80. What type of control mechanism regulates blood flow in the brain in response to changes in CO2
    levels?
    intrinsic myogenic
  81. What type of regulatory mechanism increases blood flow to regions of the brain as they become more active?
    intrinsic metabolic
  82. What type of mechanism controls blood flow to the skin?
    extrinsic by means of the sympathetic division of the ANS
  83. What happens to blood flow in the skin if ambient temperatures are low and body temperature is dropping?
    It decreases
  84. What happens to blood flow to the skin if body temperature rises?
    It increases
  85. If increased blood flow to the skin does not sufficiently lower body temperature, what additional
    measures are taken?
    Sweat glands produce sweat as a coolant and bradykinin to increase vasodilation
  86. What are the three most important factors contributing to blood pressure?
    • cardiac rate
    • stroke volume (determined primarily by blood volume)
    • peripheral resistance (determined by vasocontriction or dilation)
  87. What units are used to measure blood pressure?
    mm Hg (millimeters of mercury)
  88. What type of instrument is used to measure blood pressure?
    sphygmomanometer
  89. How does the total cross-sectional area of vessels relate to blood pressure?
    inversely (as cross-sectional area increases, blood pressure decreases)
  90. What type of receptors respond to blood pressure?
    baroreceptors
  91. Where are baroreceptors located in the body?
    the aortic arch and the carotid sinuses
  92. In relation to stimulation by a continuous stimulus, what type of receptors are baroreceptors?
    tonic
  93. What cranial nerve innervates the baroreceptor in the aortic arch?
    the vagus nerve
  94. What cranial nerve innervates the baroreceptors in the carotid sinus?
    the glossopharyngeal
  95. What neural centers control vasoconstriction/vasodilation?
    the vasomotor control centers of the medulla oblongata
  96. What neural control centers regulate cardiac rate?
    cardiac control centers in the medulla oblongata
  97. Motor fibers controlled by the medulla oblongata to regulate cardiac rate and vasocontriction/vasodilation travel through what nerves?
    vagus nerve and sympathetic nerves and spinal nerves carrying sympathetic fibers
  98. Which division of the ANS raises blood pressure?
    the sympathetic
  99. Which division of the ANS lowers blood pressure?
    the parasympathetic
  100. Baroreceptors may take a few seconds to respond to the drop in blood pressure due to an individual moving from a resting position to a standing position. This can result in dizziness or even faint because the brain is not adequately perfused. What is the medical term for this drop in blood pressure?
    postural (orthostatic) hypotension
  101. What reflex maintains proper blood pressure?
    the baroreceptor reflex
  102. If blood pressure is dropping, what two hormones which effect blood volume help to increase it?
    aldosterone and antidiuretic hormone (ADH)
  103. If blood pressure is too high, what hormone which influences blood volume helps to lower it?
    atrial natriuretic peptide (ANP)
  104. What is the medical term for an expiratory effort against a closed glottis?
    the Valsalva's maneuver
  105. What type of flow occurs when all parts of a fluid move in the same direction, parallel to the axis of the vessel?
    laminar flow
  106. What type of flow occurs when some parts of a fluid move in different diretions?
    turbulent flow
  107. What term refers to the highest blood pressure in an artery when it equals the pressure in a blood pressure cuff and the first Korotkoff sound is produced?
    systolic pressure
  108. What term refers to the lowest blood pressure in an artery when it equals the pressure in a blood pressure cuff and the last Korotkoff sound is produced?
    diastolic pressure
  109. What term refers to the difference between the systolic and diastolic pressure within an artery?
    pulse pressure
  110. Pulse pressure is a reflection of what other physiological factor?
    stroke volume
  111. What is the significance of the mean arterial pressure?
    It is the pressure that drives blood through the capillaries
  112. What formula is an approximation of mean arterial pressure?
    Mean arterial pressure = diastolic pressure + 1/3 pulse pressure
  113. What medical term means “high blood pressure”?
    hypertension
  114. What type of hypertension is a result of known disease processes?
    secondary
  115. What type of hypertension is the result of complex and poorly understood processes?
    primary (essential)
  116. Which type of hypertension is the most common?
    primary (essential)
  117. What are two major dangers of hypertension?
    • The heart must work harder to overcome the increased afterload. This leads to pathological
    • changes in heart structure
    • Damage to vessels leads to increased risk of stroke.
    • Development of atherosclerois leads to heart disease
  118. What is a toxemia of late pregnancy characterized by high blood pressure, proteinuria, and edema?
    preeclampsia
  119. What type of shock occurs due to low blood volume?
    hypovolemic
  120. What type of shock results from infection?
    septic
  121. What type of shock occurs as a result of a severe allergic reaction?
    anaphylactic
  122. What type of shock results from damage to the nervous system?
    neurogenic
  123. What type of shock results from heart failure?
    cardiogenic
  124. What is heart failure in which the heart is unable to maintain adequate circulation of blood in the tissues of the body or to pump out the venous blood returned to it by the venous circulation?
    congestive heart failure

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