The Circulatory System Essay -- essays research papers

The Circulatory SystemThe circulatory system in pulp and physiology is the course taken bythe filiation with the arteries, capillaries, and veins and back to the lovingness. Inhumans and the higher vertebrates, the heart is made up of four house theright and left(p) ears, or atria, and the right and left ventricles. The right spot of the heart pumps oxygen-poor melodic phrase from the cells of the consistency back to thelungs for new oxygen the left side of the heart receives blood rich in oxygenfrom the lungs and pumps it through the arteries to the various parts of thebody. Circulation begins early in fetal life. It is estimated that a given(p)portion of the blood completes its course of circulation in approximately 30seconds. pneumonic circulation is where the blood from the entire body istransported to the right auricle through devil large veins. The superior vena cavaand the inferior vena cava. When the right auricle contracts, it forces theblood through an opening i nto the right ventricle. Contraction of this ventricledrives the blood to the lungs. Blood is prevented from returning into theauricle by the tricuspid valve, which completely close downs during abbreviation ofthe ventricle. In its passage through the lungs, the blood is oxygenated, thatis, then it is brought back to the heart by the four pulmonary veins, whichenter the left auricle. When this chamber contracts, blood is forced into theleft ventricle and then by ventricular capsule into the aorta. The bicuspid,or mitral, valve prevents the blood from flowing back into the auricle, and thesemilunar valves at the start-off of the aorta stop it from flowing back intothe ventricle. Similar valves are present in the pulmonary artery.The aorta disjoints into a number of main branches, which in turn divideinto smaller ones until the entire body is supplied by an elaborately branching series of blood vessels. The smallest arteries divide into a fine network ofstill more than minute ve ssels, the capillaries, which have extremely thin wallsthus, the blood is enabled to come into close relation with the fluids andtissues of the body. In the capillaries, the blood performs three functions thenit releases its oxygen to the tissues, it furnishes to the body cells thenutrients and new(prenominal) essential substances that... ...itiating the heartbeat. The contraction then spreads over the auricles inthe septum amidst the auricles, it excites another leaf node called theauriculoventricular node. The auriculoventricular bundle conducts the impulsefrom this node to the muscles of the ventricles, and in this way contraction andrelaxation of the heart are coordinated. individually phase of the cardiac cycle isassociated with the production of an electrical potential that hobo be recordedby electrical instruments to produce a knowledge known as an electrocardiogram.Circulation of the blood in superficial capillaries can be observedunder the microscope. The red blood c ells can be seen despicable along rapidly inthe middle of the blood current, while the face cloth cells advance more slowly alongthe walls of the capillaries. The capillaries present a off the beaten track(predicate) larger surface withwhich the blood comes in contact than do other blood vessels end because theyconsequently offer the greatest resistance to the go along of the blood, theyhave a great influence on the circulation. Capillaries expand when temperaturerises and back up to cool the blood then they contract in cold and sustain preserveinternal heat.