Description of the Human Heart - Essay Example

Interestingly, the heart has three linings, the softer innermost layer called the endocardium, the middle region called the myocardium, and the outer fluid-filled surrounding called the pericardium. The pumping of the heart is controlled by the Sinoatrial (SA) node which is located in the posterior wall of the right atrium(Heart 1995).
To understand how the heart can perform its task of supplying blood, we should be able to note the main important parts.

1. Chambers of the heart: the heart contains four chambers, the right, the left atrium, and the left and right ventricles. These are the sites where blood collects throughout the process.
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 function of the valve is to 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 function of veins is to covey blood from and to the heart.

How the Heart Works
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 artery past the semilunar valves(Heart 1995). The process continues as the blood is returned from the lungs via the pulmonary veins where the oxygenated blood is delivered to the left atrium. Read More