Heart

The inferior and superior vena cava brings the oxygen poor blood into the right atrium, through the tricuspid valve and into the right ventricle. The ventricle pumps the blood through the pulmonary valve, into the pulmonary artery, to go and get oxygen from the lungs. Pulmonary veins are then responsible for bringing back the oxygenated blood to the left side of the heart. At this point once the blood enters the left atrium, the walls contract and push the blood through the mitral valve into the left ventricle, which has the thickest walls of all four chambers. The reason for this is because it must have a strong pump to push the blood throughout the entire body. When the left ventricle contracts it pushes the blood through the aortic valve, into the aorta. The aorta then branches off and sends blood out through the rest of the body.

There are two phases of the heartbeat the diastole and the systole. Diastole is considered as the relaxation phase. In this phase the chambers fill with blood as the heart relaxes. Systole on the other hand is considered the contraction phase. It is in this phase that the heart pumps blood into the pulmonary artery and the aorta. The heart pumps out 3 ounces of blood with each contraction. This cycle is called the diastole-systole cardiac cycle, and it occurs between 70 to 80 beats per minute. The heart has an audible sound the “lubb-dubb” which can be heard through a stethoscope. The lubb is associated with the contraction phase of the heart, which is the systole, and the dubb is the relaxation phase, which is the diastole.

A sphygmomanometer consists of a rubber bag inside a cloth cuff that is wrapped around the upper arm. The rubber is inflated with the bulb pump by the hand. Air slowly escapes from the bag, and then the pressure is slowly lower at the point when the person listening with the stethoscope first hears the loud the sounds of the pulse within the blood vessels, which is the systolic blood pressure. As it...