Several major vessels enter and exit the heart. The arteries carry blood away from the heart while the veinsBlood vessels that carry blood to the heart. bring blood to the heart. While memorizing the major vessels is unnecessary, having a basic picture of the major vessels is clinically important. The main vessel feeding the right heart is the vena cava. The right atrium also receives venous blood from the coronary sinusThe common venous outlet into the right atria that drains the heart’s venous system from the coronary arteries. Six Second ECG Guidebook (2012), T Barill, p. 194, the main venous return of the heart’s blood supply.
Approximately 65% of blood volume is normally contained in the venous system. With increased energy demands, blood flowThe purpose of the cardiac cycle is to effectively pump blood. The purpose of the cardiac cycle is to effectively pump blood. The right heart delivers deoxygenated blood to the lungs. Here oxygen is picked up and carbon dioxide is... must increase. Sympathetic nervous systemThe involuntary nervous system that provides alpha, Beta 1 and Beta 2 responses as stimulated by catecholamines – epinephrine, norepinephrine and dopamine; combined responses include increased heart rate, more forceful contraction, peripheral vasoconstriction and bronchial dilation. 1. Six Second ECG Guidebook (2012), T Barill, p. 206 stimulation is responsible for the majority of the fluctuations in blood flow during exercise, with vasodilation and vasoconstriction occurring simultaneously to increase blood flow to the vital organs (i.e. brain, muscle).
The right ventricleThe right ventricle ejects blood through the main branches of the left and right pulmonary arteries to the lungs. The chambers of the heart are the main drivers within an intricate pathway, delivering blood to the lungs for gas exchange... ejects blood through the main branches of the left and right pulmonary arteries to the lungs. The left atrium receives its oxygen-rich blood supply via four main pulmonary veins. The left ventricleThe left ventricle ejects blood into the aortic arch to the body. Within the arch, the coronary arteries branch off first followed by three main arteries that branch to the brain (carotids) and the upper thorax (subclavian artery). The chambers... ejects blood into the aortic archThe left ventricle ejects blood into the aortic arch to the body. Within the arch, the coronary arteries branch off first followed by three main arteries that branch to the brain (carotids) and the upper thorax (subclavian artery). Figure 1.6... to the body. Within the arch, the coronary arteriesThe coronary arteries provide blood to the heart tissues, carrying blood first across the epicardium, then the myocardium and finally terminating in the endocardium. The epicardium forms the outer layer of the heart. The myocardium forms the middle layer and... branch off first followed by three main arteries that branch to the brain (carotids) and the upper thorax (subclavian arteryMain vessels carrying blood from the heart; the arteries have minimal elasticity and contain approximately 20% of the blood supply. Major Vessels 1. Six Second ECG Guidebook (2012), T Barill, p. 15, 190).
Note that the lion’s share of blood volume is delivered to the muscles during exercise. During periods of cardiac ischemiaThe ability to identify cardiac ischemia, injury and infarction is vital in the management of the majority of cardiac emergencies. Most sudden cardiac deaths are associated with an ischemic episode. Patient deaths due to an acute myocardial infarction (MI) typically..., resting the muscles provide significant reductions to cardiac outputWhat is it? Why is it Vital? The amount of blood pumped out of the ventricle in a minute (most often refers to the blood pumped by the left ventricle) What is cardiac output? Simply, cardiac output is the amount... demands – and cardiac oxygen demand – thus helping to minimize the extent of the ischemic episode.
Atrial FibrillationOne of the most common dysrhythmias, the atria have a host of sites that are concurrently firing at a combined rate of 350-600/minute; since the junction allows maximum 240 impulses through per minute, the result is a chaotic rhythm most... and the Major Vessels
About 1 in 5 people over the age of 50 develop atrial fibrillation, a chaotic quivering of the atriaRight and left atria (1/3 volume and muscle mass of the ventricles) pump blood to the ventricles. Chambers and Layers of the Heart 1. Six Second ECG Guidebook (2012), T Barill, p. 190. Blood velocity typically slows along the walls of the atria from the friction between the endocardiumThe smooth innermost layer of the heart covers the inner chambers and the cardiac valves. The mechanical structures of the heart include the heart’s layers, chambers, septum, valves, and the major vessels (including the coronary arteries). Each of these structures... and the blood. As long as the atria rhythmically contract, the blood is propelled quickly forward. Without atrial contraction (i.e. atrial fibrillation), blood along the walls can slow significantly. After 48 hours, about 3-5% of people in atrial fibrillation will form a blood clot in the atria.
If this clot is dislodged from the right atrium and floats to the lungs via the pulmonary arteries, a pulmonary emboli results. If a clot develops and moves from the left atrium, the aortic arch is next in line. Of the three main vessels of the arch, two of the three vessels target the brain. As expected, atrial fibrillation is a major risk factor for cerebral vascular accidents (stroke).
Having an understanding of the mechanical structures of the heart helps us make sense of both normal physiology and pathophysiology. Looking at the ramifications of atrial fibrillation is but one example.
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 15-17