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Flashcards

Chapter 20 - The Heart

Kyha Avery Biology 1692 Resp Therapy Inglês 77 flashcards

Flashcards do conjunto (77)

  1. 1Where is the heart located?It is located directly behind the sternum, in the anterior portion of the mediastinum.
  2. 22/3 of heart is located where? Where does the other portion rest?2/3 heart's mass lies left to the midsternal line. The right side lies on the diaphragm
  3. 3What does the mediastinum contain?It contains the great vessels, the thymus gland, the esophagus, & the trachea
  4. 4What are the 3 layers of the heart?Epicardium (visceral pericardium)
    Myocardium
    Endocardium
  5. 5What does the myocardium contain? What does the endocardium line?The myocardium has cardiac muscle.
    The endocardium lines the inside of chambers & valves.
  6. 6What kind of arrangement do ventricular muscles have and why?The ventricular muscles have a spiral arrangement in order to "wring" blood out from apex to base
  7. 7What ventricle holds more blood?Trick question! They both hold the same amount of blood
  8. 8What ventricle is larger, thicker & generates higher pressure?The left ventricle
  9. 9Where do the left & right coronary arteries located?At the base of the aorta at the aortic sinuses
  10. 10How do the LA + RA work togther?They receive blood coming back to the heart. Contract together to push blood into the ventricles
  11. 11How do the RV + LV work togther?Contract together pushing blood into systemic and pulmonary circuits.
  12. 12Where do arteries carry blood? Where do veins carry blood?Arteries carry blood away from the heart.
    Veins carry blood to the heart.
  13. 13How do the free edges of AV nodes not collapse into the atrium?The free edges of AV nodes don't collapse into the atrium during contraction because they are held in place by chordae tendineae. Chordae tendineae are held in place by papillary muscle.
  14. 14What are semilunar valves?Are three thin leaflets, out-pocketing of the vessel wall
  15. 15What are the 2 types of semilunar valves?Aortic semilunar valve
    pulmonary semilunar valve
  16. 16How does deoxygenated blood flow through the right side of the heart?1.) Deoxygenated blood returns the the SVC/IVC
    2.) Blood enters the RA
    3.) Passes through the R AV valve or the tricuspid valve
    4.) Blood enters the RV
    5.) Blood passes through the pulmonary SL valve
    6.) Blood enters the pulmonary trunk
    7.) Enters L & R pulmonary Veins
  17. 17When the pressure is greater behind the valve it will....It will open
  18. 18When the pressure is greater in front of the valve it will....close
  19. 19When the ventricles are relaxed what valves are open & which ones are closed?The AV valves are open & the semilunar valves are closed
  20. 20When ventricles are contracting, what valves are open and which ones are closed?The AV valves are closed & the semilunar are open
  21. 21What is the property called that pacemaker cells have?Automaticity
  22. 22What does the SA node contain & do?Has the pacemaker cells that establish the basic heart rhythm called sinus rhythm
  23. 23What are internodal pathways?They are a system of conduction cells that run through the walls of the atria; connects the SA node to the AV Node
  24. 24What does the atrioventricular node contain?Contains the pacemaker cells
  25. 25What does the AV Bundle (Bundle of His) do?The Bundle of His carries impulses to left & right branches which conduct to Purkinje fibers & papillary muscles.
  26. 26The Purkinje fibers distribute impulses through ventricular at what time?Atrial contraction is completed
    Ventricle contraction begins
  27. 27What are 2 characteristics of pacemaker cells?1.) Pacemaker cells do not have stable resting membrane
    2.) Pacemaker potentials are spontaneous depolarizations
  28. 28What causes pacemaker potentials?They are due to the opening of voltage gated Na+ channels & the closing of voltage gated K+ channels.
  29. 29What is a VG Na+ channel also referred to as?Funny channels
  30. 30What does the P wave represent?Atrial depolarization
  31. 31What does the QRS complex represent?Ventricular depolarization
  32. 32What does the T wave represent?Ventricular repolarization
  33. 33What cells form the bulk of the heart's muscle tissue?Contractile cells
  34. 34What do contractile cells form?Forms the walls of the atria & ventricles
  35. 35What are the physical characteristics of contractile cells?These are branching cells, mostly uninucleate
  36. 36Branching cells are wrapped with what and what does it prove for the cell?Branching cells (contractile cells) are wrapped with collagen and elastic fibers for physical support & elasticity
  37. 37What are the 3 steps in ventricular contractile cells?1.) Depolarization
    2.) The plateau
    3.) Repolarization
  38. 38What causes rapid depolarization in an action potential? How long does it last?Na+ entry
    3-5 msec
  39. 39What cause the plateau in an action potential? How long does it last? How does it end?The entry of Ca+
    175 msec
    Ends with the closure of slow Ca+ channels
  40. 40What causes repolarization in an action potential? How long does it last? How does it end?K+ LOSS
    75 msec
    ends with the closure of slow K+ channels
  41. 41What prevents tetany of the heart?In cardiac muscle fibers, the absolute refractory period continues until relation is underway; the cell cannot be restimulated
  42. 42How long is the cardiac cycle?From the start of one heart beat to the next heartbeat
  43. 43What are the 2 phases of the cardiac cycle?Systole & Diastole
  44. 44What is end-diastolic volume (EDV)?It is the volume of blood in the ventricle at the end of ventricular diastole
  45. 45What is isovolumetric ventricular contraction?It is during the beginning of ventricular systole when the muscle is contracting but not enough pressure has built up to open the semilunar valves.
  46. 46What is Stroke Volume (SV)?Is the volume of blood ejected from the ventricle each beat
  47. 47When all the valves are closed, what is this called?Isovolumetric ventricular relaxation
  48. 48What causes normal heart sounds?It is caused by turbulent blood flow as the heart valve closes
  49. 49What is S1 related to?Related to the closing of the AV valves
  50. 50What is S2 related to?S2 is related to the closing of SL valves
  51. 51How do you calculate SV?SV= EDV - ESV
  52. 52What is the normal values for EDV & ESV?EDV=130 mL
    ESV= 50 mL
  53. 53What is ejection fraction (EF%)?Is the % of the end diastolic volume represented by the stroke volume
  54. 54How do you calculate EF?EF=SV/EDV
  55. 55What is a normal EF?55-60%
  56. 56How do you calculate cardiac output (CO)?CO= HR X SV (L/min)
  57. 57What 2 factors effect HR?Hormones & autonomic innervation
  58. 58What 2 factors effect SV?EDV & ESV
  59. 59What is the definition of CO?the volume of blood pumped by each ventricle in 1 minute
  60. 60What do the cardioacceleratory centers control?The control sympathetic postganglionic neurons through the cardiac nerve. NE released by sympathetic neurons increases HR. A more sustained rise in HR follows the release of epinephrine and NE by the adrenal medullae.
  61. 61What do Cardioinhibitory centers control?Controls parasympathetic postganglionic fibers through the vagus nerve. ACh released by parasympathetic motor neurons decreases the HR.
  62. 62What part of the automimic system dominates at rest?Parasympathetic tone dominates at rest
  63. 63At the right atrium, an increase in venous return will cause what?1.) Direct stimulation of the SA node causing increased HR and Increased CO
    2.) Brain bridge reflex
  64. 64What is the Bainbridge reflex?Entry of blood stimulates stretches receptors of the right atrial walls
    Triggers a reflexive increase increase in HR though increased sympathetic activity
  65. 65What 2 factors effect EDV?1.) Venous return
    2.) Filling time
  66. 66What effects venous return?Depends an CO, blood volume, peripheral circulation, & skeletal muscle activity
  67. 67What effects filling time?the duration of Ventricular diastole, which is effected by heart rate. The faster the heart rate, the less filling time.
  68. 68What is preload?refers to the degree of stretching in ventricular fibers ( the size of zone of overlap prior to contraction)
  69. 69What does the Frank-Starling law refer to?The heart will automatically adjust output to match inflow (more in = more out)
  70. 70increased sympathetic activity would have what kind of effect on contractility and ESV?Increased contractility
    decreased ESV
  71. 71What hormones increase sympathetic activity?E, NE, thyroid hormones, glucagon
  72. 72What drugs are used to mimic sympathetic (adrenergic) stimulation?Isoproterenol, dopamine, & dobutamine
  73. 73When we increase parasympathetic activity, where is the greatest reduction in contractile force within the heart? Why?In the atria because parasympathetic innervation is relatively limited in the ventricles
  74. 74What drugs are used to decrease cardiac function?Beta blockers
    Calcium channel blockers
  75. 75What is afterload?Is the pressure that must be overcome for the ventricles to open the semilunar valves & eject blood
  76. 76When does after load increase?any factor that:
    1.) Restricts arterial blood flow
    2.) Weakens the myocardium
  77. 77An increased after load causes what 3 things?1.) Extends the isovolumetric contraction phase
    2.) Less time for ejection
    3.) Increases ESV & Decreases SV

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Resp Therapy Biology 1692 FlashCards sobre Chapter 20 - The Heart, criado por Kyha Avery em 19-03-2023.
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Kyha Avery
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