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26 Cards in this Set
- Front
- Back
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Heart pumps blood into 2 circuits in sequence...
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pulmonary circuit (to/from lungs); systemic circuit (to/from rest of the body)
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Pericardial Cavity
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surrounds the heart; lined by pericardium made of two layers (primary goal is to reduce friction)--visceral pericardium (covers heart surface) and parietal pericardium (lines pericardial sac that surrounds heart
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Visceral pericardium
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epicardium--covers heart surface
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Parietal pericardium
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lines pericardial sac that surrounds heart
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Auricle
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outer portion of atrium
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coronary sulcus
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deep groove that marks boundary of atria and ventricles
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posterior interventricular sulcus (theres an anterior as well)
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mark boundary btwn left/right ventricles; sulci contain major cardiac blood vessels; filled w/protective fat
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Cardiac Muscle Cells
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Shorter than skeletal muscle fibers; have single nucleus; have striations (sarcomere organization); depend on aerobic metabolism; connected by intercalated discs
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interatrial septum
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separates atria
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desmosomes
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transmit tension
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gap junctions
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transmit action potential
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interventricular septum
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separates ventricles
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atrioventricular valves
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4--located btwn atrium and ventricle; ensure one-way flow from atrium to ventricle (left thicker than right which only goes to lungs)
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Heartbeat needs two types of cardiac cells....
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contractile cells--provide the pumping action; cells of the conducting system--generate and spread the action potential
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the conducting system
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initiates and spreads electrical impulses in heart (wave-like fashion); 2 types of cells (nodal and conducting); heart is self-exciting
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Nodal cells
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pacemaker cells; reach threshold first and set heart rate
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conducting cells
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distributes stimuli to myocardium
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normal pacemaker is the
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sinoatrial (SA) node
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impulse spreads from SA node...
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across atria, to atrioventricular (AV) node, to AV bundle and bundle branches, via purkinje fibers to ventricles
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2 phases in cardiac cycle
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systole--contraction phase; both ventricles simultaneously;;;diastole--relaxation phase
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blood volume reflexes
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stimulated by changes in venous return (VR is amt of blood entering heart); atrial reflex (speeds up heart rate and triggered by stretching wall of right atrium); frank-starling principle (increases ventricular output and triggered by stretching wall of ventricles
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Parasympathetic innervention (ANS)
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releases Ach (acetylcholine); lowers heart rate and stroke volume
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Sympathetic innervation (ANS)
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releases NE (norepinerephrine) and raises heart rate and stroke volume
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Adrenal medulla hormones (ANS)
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epinephrine, norepinephrine released; heart rate and stroke volume increased
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other hormones that increase output.. (ANS)
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thyroid hormones and glucagon
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CNS control of the heart--basic control in medulla oblongata
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cardioacceleratory center (activation of sympathetic neurons); cardioinhibitory center (governing parasympathetic neurons); higher centers; blood pressure sensors; oxygen, carbon dioxide sensors
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