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Heart (Anatomy (Cardiac Muscle (Involuntary, Striated, Smaller than…

- - - - Return blood to the heart
    - - Interconnect smallest arteries and smallest veins and exchanges dissolved gases, nutrients, and wastes between blood and surrounding tissue
    - - Carry blood away from the heart
  - - - Carries blood to and from the rest of the body
    - - Carries blood to and from gas exchange surfaces of lungs
    - - Supplies blood to muscle tissue of heart
        
        Coronary Arteries
        
        Originate at aortic sinuses and elevate blood pressure and elastic rebound of aorta maintain blood flow through coronary arteries
  - - - Arterioles are small branching vessels with high resistance
        
        Capillaries are the site of exchange between blood and tissue
        
        Venules are small converging vessels
        
        Veins are relatively large converging vessels that conduct blood to the heart
  - - - Inner serous pericardium, outer parietal layer, inner visceral layer (epicardium)
      - Pericardial cavity is between parietal visceral layers and contains pericardial fluid
      - Outer fibrous pericardium
  - - - Cardiac muscle tissue
    - - Covers inner surfaces of heart and is consistent of simple squamous epithelium and areolar tissue
    - - Covers surface of heart
  - - - Right atrium = Inferior and Superior Vena Cava with the sinoatrial node
      - Left atrium = four pulmonary veins
      - Low pressure
      - AV valves prevent backflow from ventricle to atria during systole
        
        Tricuspid = floor of RA opens into right ventricle
        
        Mitral (Bicuspid) = left atrium into left ventricle
      - Thin walled
      - Function
        
        Open passively in response to pressure changes
        
        Open when atrial pressure is greater than ventricular pressure
        
        Cusps connected to papillary muscles by chordae tendinae
        
        Closes when atrial pressure is less than ventricular pressure (during ventricular contractions); papillary muscles contract to hold chordae tendinae
    - - Characteristics
        
        Left ventricular wall is three times thicker than right ventricle
        
        Papillary muscles (3 in the right and 2 in the left)
        
        Pumping chamber creates high pressure
        
        Semilunar valves prevent backflow from aorta and pulmonary arteries to ventricle during diastole - aortic and pulmonary
        
        Thick wall
      - Function
        
        Open when ventricular pressure is greater than arterial pressure (when ventricle contracts)
        
        Closes when ventricular pressure is less than arteriole pressure (ventricle relaxes) and stops blood flow back into ventricle
        
        Three semilunar cusps
- - - - Adjust diet to lower cholesterol
      - Promote weight loss
      - Treat high blood pressure
      - Reduce stress
      - Stop smoking
      - Increase physical activity
    - - Cause vasodilation (e.g. nitroglycerin)
      - Block calcium ion movement into muscle cells (calcium ion channel blockers)
      - Block sympathetic stimulation (proprandolol or metoprolol - beta blockers)
      - Relieve pain and help dissolve clots (in MI)
      - Reduce coagulation (e.g. aspirin and coumadin)
- - - - Autorhythmic/Pacemaker cells
        
        Control and coordinate heartbeat
      - Contractile Cell
        
        Produce contractions
    - - All heart chambers contract in series, first the atria and then the ventricles
      - A single cardiac contraction