BIOL 1080 Lecture Notes - Lecture 14: Arteriole, Tachycardia, Acetylcholine
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Valves control blood flow: lub --> av valves close (r = tricuspid valve / l = mitral valve, dub --> semilunar valves close (b/w ventricles and arteries) Ex: stenosis = narrowing of the valve! Can cause fatigue / shortness of breath / exercise intolerance / heart failure. Ex: porcine (from pig) --> but will need immunosuppressants: the cardiac cycle, contraction of atria, contraction of ventricle, rest, contraction = systole (ex: 120/80, relaxation = diastole (ex: 120/80) Referred to as the afterload (pressure during rest in heart) If too high ==> means that heart has to work harder to pump / has to overcome higher resistance to eject the same amount of blood! Intercalated disks: sa node, av node, bundle of his, bundle branches (splits into left and right, purkinje fibers, problems with conduction. Abnormal sa node firing (tachycardia (fast) / bradycardia (slow)) Normally - sa node fires at 100bpm! (but resting heart rate is less b/c parasympathetic ns)
