PSIO 202 1nd EditionExam # 1 Study Guide Lectures: 1 - 10Lecture 1 (August 25)I. Systemic Circulation (arterialized)a. Carries oxygenated blood from the aorta to the tissuesb. The left ventricle ejects blood into the aortac. Blood is distributed to 6 major organ systemsi. Brain, kidneys, muscles, GI system, and skind. This circulation happens in parallel vs. in series that way the same mixture of oxygenated blood is spread evenly to all the systemsII. Pulmonary Circulation (venous blood)a. The right ventricle ejects blood into the pulmonary circulation that returns from the organ systemb. Carries deoxygenated blood to the lungs and then back to the heartc. The blood that leaves the pulmonary circulation (arterial blood) enters the left atriumIII. Pathway of Blood through the Heart and Lungsa. Right atriumi. Tricuspid valveb. Right ventriclei. Pulmonary valvec. Pulmonary trunk and pulmonary arteriesd. Pulmonary capillaries (blood loses CO2 and gains O2)e. Pulmonary veinsf. Left atriumi. Bicuspid valveg. Left ventriclei. Aortic valveh. Aorta and systemic arteriesi. Systemic capillaries (blood loses O2 and gains CO2)j. Super vena cava; Inferior vena cava; Coronary sinusIV. What is cardiac output?a. The amount of blood pumped by the ventricles per unit timeb. At rest, the left and right ventricles each pump 5.0 liters of blood /minute (L/min)c. This amount increases to as much as 30 L/min during maximal exerciseV. How many chambers in the heart?a. The mammalian heart is composed of four chambersi. The right atriumii. The left atriumiii. The right ventricleiv. The left ventricleb. The left ventricle has much more muscle and is much thicker than the right ventricleVI. Heart Valves sa. Four “one-way” valvesb. These insure that the blood flows in one direction, from the heart to the tissues and back to the heartc. Two atrioventricular valves between atria and ventriclesi. The tricuspid is located in the right atrium 1. Separates the right atrium and right ventricleii. The bicuspid is located in the left atrium1. Also called the mitral valve2. Separates the left atrium and left ventricleiii. The tissue flaps of the AV valves have tendons known as chordae tendinaeiv. Chordae tendinae attach to the valve cusps to the inner ventricular wallsv. They prevent “prolapse” of the valves into the atria during ventricular contractionvi. Specialized muscles known as papillary muscles regulate tension in the chordae tendinae and contract simultaneously with the ventriclesd. Two semilunar valves (between left ventricle and aorta and between right ventricle and pulmonary trunk) – these are both pressure dependenti. Aortic semilunar valve1. Separates the left ventricular chamber from the aorta2. 100 mmHgii. Pulmonary semilunar valve1. Separates the right ventricular chamber from the main pulmonary trunk2. 30 mmHgVII. Blood supply to the Heart Musclesa. The tissues of the heart are supplied with blood from the coronary circulationb. The right coronary artery originates on the ascending aortai. This supplies the sinoatrial (SA) node, the atrocentricular (AV) node, parts of the right atrium, the interventricular septum, the right ventricle, and the leftventricleii. The marginal branch originates on the right coronary and supplies the anterior portions of the right ventricleiii. The posterior interventricular branch originates on the right coronary and supplies the posterior portions of both ventriclesc. The left coronary artery originates on the ascending aorta i. Supplies the SA node, parts of the left atrium, interventricular septum, and ventriclesii. The circumflex branch supplies the left atrium and posterior regions of the left ventricleiii. The anterior interventricular branch originates from the left coronary and supplies the anterior portions of both ventriclesVIII. The coronary veinsa. The Great Cardiac drains the anterior heartb. Middle cardiac vein the posterior heartc. Both of these drain into the coronary sinus which then drains into t he right atriumLecture 2 (August 27)I. Structure of the Cardiac Musclea. Consists of branched, striated fibers with one or two centrally located nucleib. Actin and myosin are packaged in myofibrils, as they are in skeletal musclec. The branched pattern forms a network that can facilitate the transmission of electrical impulses in all directionsd. Cardiac muscle is a synctium (functions together to contract) of many heart muscle cellse. Contraction from apex upII. Gap junctionsa. Small channels which allow electrical impulses to pass quickly from one cell to the next and spread rapidly throughout the heart muscleb. Located in “intercalated discs” which lie between adjacent muscle cellsc. Intercalated discs also contain desmosomes hold adjacent cells togetherIII. How the heart muscle contracts:a. Sinoatrial nodeb. Atrioventricular nodec. AV bundle (Bundle of His)d. Right and left bundle branchese. Conducting myofibrils (purkinje fibers)IV. Conduction system of the Hearta. The pacemaker (SA node) is a mass of cells in the right atrial wallb. Pacemaker cells spontaneously discharge action potentials at a rate of 100-120+ per minutec. Autonomic nerves modify the rate of discharge, so that the resting “heart rate” is about 70 b/mind. The atria and ventricles must contract in a coordinated fashione. The sequence of cardiac muscle excitation is such that the first event is depolarized of the SA nodef. The impulses then travel down and across both atria, causing atrial muscle fiber contractiong. At the AV border here is a band of poorly-conducting tissue (small fibers, few gap junctions)h. The presence of the poorly-conducting tissue slows the impulse by about 0.1 seci. This gives the atria time to fully empty before the ventricles begin to contractj. The AV bundle leads to right and left bundle branchesk. These transmit the action potential into the muscle of both ventriclesl. The sequence of excitation is such that lower portions of the ventricles contract first, pushing the blood upwardsV. Intrinsic Conduction System-SA node:a. Pacemaker cells are auto-rhythmic cellsb. Initiates action potentials spontaneouslyc. Have unstable resting potentials called pacemaker potentials – leak currentsd. Ca++ influx, RATHER THAN NA+ accounts for the rising phase of the action potentiale. This is shown aboveVI. Cardiac Muscle Action Potentiala. Rapid depolarization due to Na+ inflow when voltage-gated fast Na+ channels openb. Plateau (maintained