The Circulatory System Essay -- essays research papers

The Circulatory agreementThe circulatory system in anatomy and physiology is the argument taken bythe argumentation finished the arteries, capillaries, and veins and subscribe to the face. Inhumans and the higher vertebrates, the heart is made up of four chambers theright and left pinnules, or atria, and the right and left ventricles. The rightside of the heart pumps oxygen-poor line of c departureit from the cells of the be back to thelungs for new oxygen the left side of the heart receives beginning rich in oxygenfrom the lungs and pumps it through the arteries to the various parts of the system. Circulation begins azoic in fetal life. It is estimated that a givenportion of the inception completes its course of circulation in approximately 30seconds.Pulmonary circulation is where the blood from the entire ashes istransported to the right auricle through two large veins. The superior vein cavaand the inferior vena cava. When the right auricle contracts, it forces the blood through an go-ahead into 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 closes during compression ofthe ventricle. In its passage through the lungs, the blood is oxygenated, thatis, indeed it is brought back to the heart by the four pulmonic veins, whichenter the left auricle. When this chamber contracts, blood is forced into theleft ventricle and then by ventricular concretion into the aorta. The bicuspid,or mitral, valve prevents the blood from move back into the auricle, and thesemilunar valves at the beginning of the aorta stop it from flowing back intothe ventricle. Similar valves are present in the pulmonary artery.The aorta divides into a fleck of main branches, which in turn divideinto smaller ones until the entire body is supplied by an elaborately branchingseries of blood vessels. The smallest arteries divide into a fine network ofstill more minute vessels, the capillaries, which have super 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 other essential substances that... ...itiating the heartbeat. The contraction then spreads over the auricles inthe septum between the auricles, it excites another node called the atrioventricular 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. Each phase of the cardiac oscillation isassociated with the production of an electrical potential that can be recordedby electrical instruments to produce a reading known as an electrocardiogram.Circulation of the blood in superficial capillaries can be observedunder the microscope. The red blood cells can be see n moving along rapidly inthe middle of the blood current, while the white cells advance more slow alongthe walls of the capillaries. The capillaries present a far larger surface withwhich the blood comes in contact than do other blood vessels end because theytherefore offer the corkingest resistance to the progress of the blood, theyhave a great influence on the circulation. Capillaries expand when temperaturerises and help to cool the blood then they contract in cold and help preserveinternal heat.