chapter 18.txt

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chapter 18.txt
2011-06-01 22:16:42
bio exam

bio 168 exam 2 ch 18
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  1. Describe the location of the heart:
    • In the mediasinum
    • Medial to the lungs
    • Deep to the sternum
    • Anterior to the spine
  2. Name the layers of the heart in order
    • Fibrous pericardium
    • Parietal layer
    • Pericardial cavity
    • Visceral layer
    • Myocardium
    • Endocardium
    • Heart chamber
  3. The suffix "-itis" refers to "inflammation of", what is endocarditis?
    Inflammation of the inner most lining of the chamber of the heart
  4. Which chamber has the thickest walls?
  5. List the three circulatory circuits:
    • 1.Pulmonary circuit - from heart to lungs and back
    • 2.Systemic circuit - blood from heart to rest of body and back
    • 3.Coronary circuit - blood from heart to tissues of heart and back.
  6. In the pulmonary circuit, arteries carry ______ blood to the lungs to oxygen. The pulmonary veins carry _____ blood back to the heard.
    • Deoxygenated
    • Oxygenated
  7. Coronary circuit carries oxygenated blood to the heart tissues. Vessels tend to run in depressions called a ______.
  8. Compare and contract semilunar valves and atrioventricular valves.
    • There is the aortic semilunar valve, and the pulmonary semilunar valve, they prevent back flow into the associated ventricles.
    • The two atrioventricular valves are located at each atrio-ventricular junction, the prevent backflow into the atria when the ventricles are contraction.
  9. Discuss the location of the pericardium and the location of the pericardial cavity.
    • � The heart is enclosed in a double-walled sac.
    • � It protects the heart,
    • � anchors it to surrounding structures,
    • � and prevents overfilling of the heart with blood
  10. Describe the histological structure of the myocardium and the significance of intercalated discs.
    The myocardium is the muscular layer of the heart. The branching cardiac muscle cells are tethered to one another by crisscrossing connective tissue and arranged in spiral or circular bundles. The intercalacted discs give continuity to the heart muscles, contain gap junctions and help the heart function as one.
  11. Compare and contrast skeletal muscle tissue and cardiac muscle tissue.
    Cardiac muscle is striated, it contacts by the sliding filament mechanism , but skeletal muscle is long, cylindrical, multinucleated skeletal muscle fibers. Cardiac muscle has intercalated discs
  12. Compare and contrast deoxygenated and oxygenated blood.
    Oxygenated blood is blood in which oxygen is attached to the hemoglobin molecules in the red blood cells. It is bright red because the attached oxygen makes the normally blue hemoglobin molecules turn red. When blood has delivered oxygen to the cells, it is described as deoxygenated. It now looks a very dark red because so many of the hemoglobin molecules have turned blue again. The mixture of blue and red molecules looks dark red to our eyes.
  13. 18b.
    • List three vessels that bring blood into the heart and identify their entry points.
    • � Superior vena cava
    • � Inferior vena cava
    • � Coronary sinus
  14. Identify the vessel which allow the blood to leave the heart.
  15. Describe the path blood flows as it flows thought the heart from the point of entry through the point of leaving to join systemic circulation. Including the chambers, valves, and vessels will pass thought.
    Right atrium from the superior, inferior vena cava and coronary sinus, to the right ventricle, then it passes through the pulmonary trunk via the pulmonary semilunar valve, and then it is pumped to the lungs via the pulmonary arteries. Once the blood becomes oxygenated it is pumped into the left atrium via the pulmonary veins, it is then shunted into the left ventricle. It now passes to the aorta from the aortic semilunar valve and then distributed to the body.
  16. Describe the flow of the blood thought the fetal heart and discuss how it differs from the adult heart.
    Blood skips pulmonary circuit. It travels directly to the left atrium via the foramen ovale. Where in the adult heart there is the fossa ovalis which is just a depression as opposed to a passage way. There is also a passage way from the pulmonary trunk to the aorta via the ductus arterious, which is the ligamentum arteriosum in the adult heart, which is fibrous remnants.
  17. Impulses ravel thought the heart, regulating the contraction of the heart. Where do these impulses come from?
    Autonomic nervous system
  18. What does an �ECG tracing� race?
  19. _____junctions between cardiac cells transmit impulses from cell to cell making ------- ----- of cells in the tissue possible.
    • Gap junctions
    • Simultaneous contraction
  20. Depolarization =
  21. Repolarization =
  22. Describe how the impulse that travels thought the heart is depicted by the ECG as waves of repolaization/depolarization occur. P wave =
    Depolarization of atria
  23. Describe how the impulse that travels thought the heart is depicted by the ECG as waves of repolaization/depolarization occur. QRS wave =
    Repolarization of atria, and depolarization of ventricles
  24. Describe how the impulse that travels thought the heart is depicted by the ECG as waves of repolaization/depolarization occur. T wave =
    Repolaization of ventricles
  25. List the parts of the conduction system and explain how the system functions o control efficient pumping of the heart.
    • 1. SA node (pacemaker)= generates impulse
    • 2. AV node = impulses pauses
    • 3. AV bundle = connects the atria to the ventricles
    • 4. Bundle branches = conduct the impulses thought the interventricular septum
    • 5. Purkinje fibers = depolarize the contractile cells of both ventricles.
  26. Describe the innervations of the SA node, the involvement of the autonomic nervous system, and discuss the function of the SA node in respect to the pacing of the heart.
    It sets the pace of the heart as a whole because no other region of the conduction system has a faster depolarization rate. � sinus rhythm
  27. 18c.
  28. Define: Cardiac Cycle
    All the events that occur in the heart during one complete heart beat
  29. Describe, in your own words, how atrioventricular valves function. Be sure to include the importance of pressure differentials between the atria and the ventricles.
    Atria fills when atrial pressure is greater then ventricular pressure. The blood pushes the valve open. Then once the pressure is greater in the ventricle then the atria it closes the valve. Once ventricles contract blood pushes out and lower pressure etc. all based on pressure differentials between atria and ventricles�.
  30. What are the roles of chordae tendineae and papillary muscles
    They help hold the valves in place so they don�t of back into the atria.
  31. Describe, in your own words, how semilunar valves function. Be sure to include the importance of pressure differentials.
    As ventricles contract, pressure increases and pushes against semilunar valves, onece ventricular pressure is greater then aortic or pulmonary pressure it pushes blood thought the valve, and onces the pressure in the aorta is greater then the ventricles its shuts the valve.
  32. List the phases of the cardiac cycle.
    • 1. Ventricular filling � ventricles fill
    • 2. Ejection period � ventricles contract
    • a. Isovolumetric contraction � both valves closed. Nothing leaving
    • b. Ejection period � valves open, blood ejects from ventricles to arteries
    • 3. Isovolumetric relaxation � ventricle relax � valves open
  33. Explain how atrial systole is related to ventricular filling.
    Systole is the contraction period. Atrial systole is when the atria is contracting the pressure differential in the ventricle causes the ventricle to fill onces the pressure is greater in the ventricle then artia it forces the blood into the atria
  34. Define: systolic BP
    Pressure exerted by the blood on the walls of the vessles during ventricular contraction.
  35. Define: Diastolic BP
    Arterial BPreached during or as a result o diastole; lowers level of any given cardiac cycle
  36. Define: Dicrotic notch and discuss why it appears.
    Closure of the aortic valve causes a brief rise in aortic pressure as back flowing blood rebounds off the closed valve cusps
  37. Define: Heart murmur
    Abnormal heart sound usually resulting from valve problems
  38. Which valve closure results in the first heats sound?
    AV valve
  39. Which valve closure results in the second heart sound
    Semilunar valve
  40. Heart rate set b the firing of the SA node. How does the SA node know when to fire? B control from the?
    Medullary centers in the medullar oblongata
  41. Name the two centers found in the medulla oblongata
    • 1. Cardioacceleratory center
    • 2. Cardioinhibitory center
  42. CAC is the
  43. CIC is the
  44. Type of nerve: CAC
  45. Name of nerve: CAC
    Cardiac nerve
  46. Chemical signal released: CAC
  47. Heart rate change: CAC
  48. Contraction force change: CAC
  49. Type of nerve: CIC
  50. Name of nerve: CIC
  51. Chemical signal released: CIC
    ACH (actacholine)
  52. Heart rate change: CIC
  53. Contraction force change: CIC
  54. The medulla reacts to changes in the body and send the appropriate signal via the CAC or CIC to t return the body to homeostasis. For this to happen, the body must send siginals to the medulla to process. Where do some of these signals come from? What are they measureing.
    • Baroreceptors � specialized centers that detects BP
    • Stimulation of the baroreceptors will send mssages to the CAC and or CIC therefore by effecting the HR and BP
  55. List the areas where barorecetors are found
    • 1. Carotid sinus (arterial BP)
    • 2. Aortic arch (aterial BP)
    • 3. Superior vena cava (venous BP)
    • 4. Inferior vena cava (venous BP)
    • 5. Wall of right atrium
  56. Discuss the effects of increased and decreased BP sensed by the carotid sinus and the aortic arch.
    • Stimulus: increased BP = stimulates COC and inhibits CAC
    • Stimulus: decreased BP � stimulates CAC
  57. Besides BP what other factors indulcence BP?
    • Chemicals
    • Temp
    • Strong emotions
    • Sex
    • Age
  58. How does the presesnce of th epinephrine effect heart rate?
    • 1. Increase SA noe exicatibility
    • 2. Increase heart rate and contraction force
    • 3. Stimulates adrenal medulla
  59. What is the effect of temperature changes on heart rate?
    • Increased body temp = increased HR
    • Decreasd body temp a= decreased HR
  60. What is the advantage of leowering temp in operating rooms?
    Long surgery = slow on purpose = lower HR less blood being pumped � less lost.
  61. How does stress affect Hr?
  62. How does depression affect HR?
  63. How does sex adfect heart rate?
    Female HR greater then male HR
  64. How does age affect Hr?
    Younger HR greater then older HR
  65. Define: systole
    Contraction period
  66. Define: diastole
    Relaxation period
  67. 18d.
  68. Define: cardiac output
    The volume of blood pumped by the heart in one minute
  69. Why would one measure cardiac output?
    Used to monitor changes in patient conditions and compare overall cardiac health to the mean
  70. Write the formula for figuring out cardiac output.
    • CO=HR*SV
    • CO = cardiac output � Vol/min
    • HR = heart rate � beats/min
    • SV = stroke volume - vol/beat
  71. Given normal values of 75BPM for heart rate, 70ml/beat for stroke volume, calculate the cardiac output for a normal situations.
    75 beats/min * 70ml/beat = 5.25 L/min
  72. Increase in HR will cause ______ in cardiac output.
  73. Decrease in HR will cause ______ in cardiac output
  74. Increase in SV will cause ____ in cardiac output
  75. Decrease in SV will cause _______ in cardiac output.
  76. How is heart rate regulated?
    By medullary centers and baroreceptors
  77. Define: stroke volume
    • The volume of blood expelled by the heart in one complete hear beat
    • EDV-ESV
  78. Define: end systolic volume
    Volume in the ventricle at the end of contraction and expulsion of blood
  79. Define: end diastolic volume
    Volume in the ventricles at the end of the filling period
  80. Give the formula to figure out stroke volume
    SV = EDV � ESV
  81. An increase in EDV will cause a _____ in stroke volume, which in tureen will cause a ____ in cardiac output.
    • Increase
    • Increase
  82. A decrease in EDV will cause a _____ in stroke volume, which in tureen will cause a ____ in cardiac output.
    • Decrease
    • Decrease
  83. An increase in ESV will cause a _____ in stroke volume, which in tureen will cause a ____ in cardiac output.
    • Decrease
    • Decrease
  84. A decrease in ESV will cause a _____ in stroke volume, which in tureen will cause a ____ in cardiac output.
    • Increase
    • Increase
  85. How does an increase in heart rate affect EDV? Why? What affect will this have on SV?
    • � Length of filling time
    • � Longer fill time, more V fit in ventricle
    • � Increased HR = Decreased filling time = Decreased EDV
  86. How does venous pressure affect EDV?
    • � Higher venous pressure, increased amount of blood entering the heart
    • � Within a given time = increased EDV
  87. How does an increase in arterial blood pressure affect the function of the semilunar valve?
    Force ventricular contraction
  88. How will forced ventricular contraction affect ESV? Why?
    • � Forced of contraction must exceed arterial pressure before semi lunar valve will open and expel blood.
    • � Increased AP = Decreased emptying time = decreased volume expelled = Increase ESV = decrease SV
  89. How does the force of ventricular contraction effect ESV? SV? CO?
    • ESV = decreased
    • SV = Increase
    • CO = Increase
    • Greater force = more expelled during a given time = decreased ESV = Increase SV and increased CO.
  90. List the factors involved in the control of ventricular contraction?
    • � Length of muscle fibers
    • � Nervous system chemicals
    • � Body temperature
    • � Emotions
  91. Which of the factors above are genetically determined?
    Muscle fibers and nervous system chemicals
  92. Which can we make a conscious effort to change?
  93. Which can aerobic exercise change?
    Body temperature
  94. State �starling�s Law�:
    Force of muscular contraction is determined by the length of cardiac muscle fibers. The greater the length, the stronger the contraction ( within reason).
  95. Discuss the factors which can cause an increase in EDV?
    • � Increase stretch of ventricle wall
    • � Increase Muscle fiber length
    • � Increased force of contraction
    • � Decreased ESV: more pusched out = less left in
    • � Increased SV
  96. Demonstrate the importance of EDV on cardiac output.
    • � Increased EDV = Increased SV and Decrease in ESV = Big increase in SV
    • � CO = HR * SV
    • � Therefore Increased EDV = big increase in CO
  97. How does regular exercise, and the ensuing conditioning of the heart muscle, help the efficiency of cardiac function and therefore overall cardiac health?
    � Greater force of ventricular contraction the more fluid is expelled in a given time period, so stronger heart muscles = lower ESV which means greater SV and greater CO. Therefore the reason to get cardiac exercise on a regular basis can increase the efficiency of the heart
  98. What is the function of the bicuspid valve?
    To allow one directional flow of blood from the left atria to the left ventricle at the proper time.
  99. What structure is commonly called the �pacemaker?� Why?
    SA node is called the pacemaker because it receives signals from the ANS and passes on signals which tell the heart how often to beat, ie sets the pace of the heart.
  100. 1.(5 points) Discuss how the circulation through the fetal heart differs from circulation through the adult heart. (Answer on back of this page.)
    • Fetal flow essay must include the following points
    • Fossa ovalis in adult hear is the foramen ovale in the fetla heart, allowing flow from one atria to the other.
    • 1)Ligamentum arteriosum in the adult heart is the ductus arteriosum in the fetal heart allowing blood to flow from the pulmonary trunk t the aorta
    • 2)A portion (1/2 point) of the blood will bypass the lungs using the alternate routes because the lungs do not oxygenate (1/2 oint) the fetal blood. Not ALL blood goes through the fossa ovalis (or there wouldn�t be any left in the pulmonary trunk to go through the ductus arteriosum.) or through the ductus arteriosum.