BIOH 113 1st Edition Lecture 10Outline of Last Lecture I. Heart AnatomyII. Layers of the HeartIII. External HeartIV. Atria and VentriclesV. Coronary CirculationVI. Fetal StructuresVII. Microscopic Anatomy of Heart MuscleOutline of Current Lecture I. Membrane PotentialII. Cardiac Muscle ContractionIII. Heart physiologyCurrent LectureI. Membrane Potentiala. Voltage across membraneb. Resting membrane potentialc. Ranges from -20 to 200 mVd. Results from Na+ and K+ concentration gradients across the membranee. Steady state: potential maintained by active transport of ionsII. Cardiac Muscle Contractiona. Heart muscle:i. Stimulated by nerved and is self excitable—automaticityii. Contracts as a unitb. The actual events of cardiac muscle contraction are similar to skeletal muscle contractionIII. Heart Physiology:These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Intrinsic Conduction System: i. Autorhythmic cells:1. Initiate action potentials2. Have unstable resting potentials called pacemaker potentials that are a result of Na+ channels3. Use calcium influx for rising phase of the action potentialii. Contractile cells are connected to autorhythmic cells via gap junctions buthave some different membrane properties1. Chief among which is stable resting membrane
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