|
|
|
|
The Heart
|
|
|
Each part has a receiving chamber, called the atrium, and an ejecting chamber, called the ventricle. The ventricles have a thick muscular wall, the myocardium, which contracts regularly (at rest, at a rate of 60 to 70 times a minute) to pump the blood towards the various organs; as the blood flows in the arteries, it produces a characteristic beat called the pulse. The atria are separated from the ventricles by valves (the tricuspid valve to the right and the mitral valve to the left), which have a one-way action: when the ventricle contracts to squeeze the blood out into the artery, they prevent the blood from flowing backwards into the atrium; there are also valves at the ventricle exits (the pulmonary valve at the exit of the right ventricle and the aortic valve at the exit of the left ventricle) which prevent the blood, during diastole, from "flowing backwards" towards the ventricle after being squeezed out into the artery.
For the myocardium to function normally, it must, like all the other organs, receive oxygen-rich blood; this blood is brought to it by the coronary arteries, which are the first branches of the initial aorta, starting a few centimetres from where it begins. |
|
|
When the heart is functioning normally, the coronary arteries provide a normal supply of blood to the myocardium, and thus the myocardium and valves function properly.
|
© 2009 LES LABORATOIRES SERVIER,
an incorporated company of SERVIER
All Rights Reserved -
Terms of Use
Page last updated on 31/01/2008 -
Get the latest updates
SERVIER does not sell its products over the Internet -
More information