Discription Essay Example | Topics and Well Written Essays - 500 words - 1

Discription - Essay Example The pumping of the heart is controlled by the Sino atrial (SA) node that is located in the posterior wall of the right atrium(Heart 1995). 2. The valves: there are two types of valves the Atrioventricular valves (located in the middle of the heart between the ventricle and the atria) of two types the tricuspid on the right and mitral/cuspid on the left and the Semilunar valves of two types pulmonary and the aortic valve. The functions of the valve is too prevent the backflow of blood to the chambers. 3. The vessels: There are four main vessels in the heart; the vena cava divided into superior and inferior, the pulmonary artery, the pulmonary vein and the aorta. The functions of veins is to covey blood from and to the heart. The heart is divided into four chambers: the top two chambers are known as the atriums and the bottom two chambers are called ventricles. Importantly, the atriums both contract at the same time same as the two ventricles(Heart 1995). First and foremost, deoxygenated blood enters the heart via the superior and the inferior vena cava into the right atrium. The right atrium contracts and forces the blood to rush into the right ventricle through the tricuspid valve. Consequently, when the right ventricle contracts, the deoxygenated blood is pumped into both lungs through the pulmonary arterypast the semi lunar valves(Heart 1995). The process continuesas the blood is returned from the lungs via the pulmonary veins wherethe oxygenated blood is delivered to the left atrium. When the atrium contracts the blood is rushed through the valves into the left ventricle, thestrongest and most muscular portion of the heart.When the left ventricle contracts, blood is rushed through the aort a: he aorta is the main artery leaving the heart (Lewis 1925). Through this process, oxygenated blood is now taken throughout