The Heart

Study Guide

1. Describe the relationships of the pulmonary and systemic circuits and differentiate them in terms of volume, length and pressure.

2. Identify the structure, arrangement, and functions of the endocardium, myocardium, and pericardium (visceral [epicardium], parietal) of the heart Terms: serous membrane, fibrous membrane, interatrial septum, interventricular septum, fibrous skeleton.

3. Identify and compare the structures, locations and functions of the atria (right, left), ventricles (right, left), atrioventricular valves (tricuspid, bicuspid, mitral), semilunar valves (pulmonary, aortic), pulmonary trunk, pulmonary arteries, pulmonary veins, aorta, superior vena cava, inferior vena cava, chordae tendineae, papillary muscles, trabeculae carnae, auricles.

4. Describe the blood flow through the heart including all valves, vessels and chambers in order of their occurrence. Be able, at any point in the pathway, to identify whether the blood is oxygenated or deoxygenated, where it has immediately come from, where it goes next, etc. Describe the simultaneous nature of this flow on the right and left sides of the heart.

5. Describe the structure and functioning of the one-way valves and relate their opening and closing to the events of the cardiac cycle and to the heart sounds. Terms: incompetence, stenosis, regurgitation, prolapsed valve.

6. Describe the events of the cardiac cycle in sequence, including pressure changes, blood flow, valve openings and closings, and heart sounds. Terms: systole, diastole, isovolumetric contraction phase, isovolumetric relaxation phase, ventricular ejection phase, quiescent period.

7. Describe the structural and physiological characteristics of cardiac muscle which are important to its function in the cardiac cycle and conduction system of the heart. Terms: contractile cells, myogenic, automaticity, rhythmicity, intercalated disks, refractory period, functional syncytium, pacemaker potential, slow calcium channels.

8. Describe the locations and functions of components in the heart's electrical conduction system and their relationship to the electrocardiogram (ECG or EKG). Describe the sequence of events in the impulse conduction of the heart. Terms: SA node, AV node, Bundle of His, bundle branches, Purkinje fibers, natural pacemaker, ectopic pacemaker, sinus rhythm, contractility.

9. Identify the waves of the ECG and relate them to the heart's conduction system. Describe how the ECG would vary with a heart block or damage to the heart's natural pacemaker. Terms: P wave, QRS complex, T wave, fibrillation, P-R interval, S-T interval.

10. Define what is meant by cardiac output (CO) and explain its calculation and the factors which affect it. Include: minute volume, stroke volume (SV), heart rate (HR), end diastolic volume (EDV), end systolic volume (ESV), ejection fraction, venous return, peripheral resistance, preload, afterload.

11. Describe the mechanisms which control cardiac rate and strength. Include: sympathetic division, parasympathetic division, cardioacceleratory center, cardioinhibitory center, vagus nerve, medulla, baroreceptors, chemoreceptors, carotid reflexes, aortic reflex, Bainbridge (right heart) reflex, higher brain centers, intrinsic controls, Starling's Law. Terms: tachycardia, bradycardia, congestive heart failure, vagal tone, length-tension relationship.