heart ch 20 m flashcards.txt

  1. heart wall layers
    • epicardium: external layer
    • myocardium: cardiac muscle
    • endocardium: inner layer
  2. av valves
    • from RA to RV: tricuspid valve
    • from LA to LV: bicuspid (mitral) valve
  3. Semilunar valves
    • exiting the RV: pulmonary valve
    • exiting the LV: aortic valve
  4. Right Ventricle
    forms ANTERIOR surface of the heart
  5. Left Ventricle
    • THICKEST chamber of the heart
    • Forms the APEX
    • Some blood flows into coronary arteries, rest into the body
  6. thickness of Myocardium
    Left ventricle works harder to maintain same blood flow as right
  7. cycle of contraction/relaxing
    • When atrium is contracting, ventricle must be RELAXING to obtain the blood (papillary muscles RELAX and Chordae tendinae slack)
    • valves open when ventricle pressure exceeds artery pressure. Some backflow is permitted here
  8. SYSTEMIC Circulation
    • STARTS with RECEIVING blood from the lungs in LEFT ATRIUM
    • Ends with veins leading back to RIGHT atrium
  9. PULMONARY Circulation
    • STARTS with blood RECEIVED from RIGHT Atrium
    • ENDS with blood taken to LEFT ATRIUM via Pulmonary VEINS
    Allow heart muscle to receive Sufficient OXYGEN
  11. Autorhythmic FIBERS
    • Specialized cardiac muscle fibers
    • 1. Act as pacemaker
    • 2. Form conduction system
  12. Conduction pathway
    • 1. starts in SA node (RA) & goes thru gap jxns to
    • 2. AV node in interatrial septum
    • 3. enters AV BUNDLE of His (action potential conducted from atria - ventricles)
    • 4. enters thru interventricular septum
    • 5. PURKINJE fibers conduct ap to myocardium ---ventricles contract
  13. AV node
    • act as pacemaker
    • rhythm control
  14. NERVE impulses
    modify STRENGTH of each heartbeat, NOT RHYTHYM
  15. Autonomic regulation
    • Norepinephrine: in SA & AV node it INCREASES the rate of depolarization
    • in contractile fibers it enhances Ca entry to INCREASE contractility
  16. Parasympathetic system
    releases Acetylcholine: SLOWS depolarization
Card Set
heart ch 20 m flashcards.txt