The cardiovascular system

Heart

The heart is a muscular organ located in the middle of the chest that has both the right and the left, an upper chamber (atrium), which receives blood and a lower chamber (ventricle), which ejects.

To ensure that blood flows in one direction, the ventricles have valves.

The four heart valves include the following:

1. bicuspid or mitral valve: Prevents the return of blood from the left ventricle to the left atrium.

2. tricuspid valve: Prevents the return of blood from the right ventricle to the right atrium.

3. sigmoid aortic valve: Prevents the return of blood from the aorta to the left ventricle.

4. pulmonary semilunar valve: Prevents pulmonary blood returns through the right ventricle.

The primary function of the heart is to pump blood throughout the vascular system to deliver oxygen throughout the body and at the same time, release of waste products (carbon dioxide). Specifically, this function involves collecting blood, oxygen deficient body and pumping it to the lungs, where it picks up oxygen and releases carbon dioxide; then the heart leads this oxygen-rich blood to all tissues of the body.

Cardiac function

With each heartbeat, while the heart chambers are relaxed, they fill with blood (period called diastole) and when they contract, the expelled (period called systole). The two atria relax and contract together, like the ventricles.

The blood circulation in the heart happens as follows. First, the oxygen-poor blood and overloaded with carbon dioxide from the entire body reaches the right atrium through two large veins (veins superior and inferior vena cava) that converge just before the heart. When the right atrium fills, forces blood into the right ventricle; when it is full, pumped through the pulmonary valve into the pulmonary arteries to reach the lungs. In these, the blood flows through tiny capillaries surrounding the air sacs, absorbing carbon dioxide and releasing oxygen, which is then exhaled. The oxygen-rich blood, and circulates through the pulmonary veins to the left atrium.

This circuit between the right heart, lungs, and the left atrium is called pulmonary circulation. When the left atrium fills pushes oxygen-rich blood into the left ventricle; when it is filled in turn, forces blood through the aortic valve into the aorta, the body's largest artery from which emerge all other arteries. This supplies oxygen-rich blood throughout the body except the lungs.

Blood vessels

The rest of the circulatory system (cardiovascular) comprises a branched system of arteries, arterioles, capillaries, venules and veins. The arteries, strong and flexible, carry blood from the heart and support the increased blood pressure. Its elasticity keeps an almost constant between each heartbeat blood pressure.

Arteries and arterioles are smaller muscular walls adjusting its diameter in order to increase or decrease the blood flow to a particular zone. The capillaries are tiny vessels with extremely thin walls, which act as bridges between the arteries (which carry blood from the heart) and veins (which carry it back to him). On one hand, the capillaries allow oxygen and nutrients to pass from the blood into tissues and secondly, also let pass waste products from the tissues into the blood.

The capillaries drain into venules, which in turn flow into the veins leading to the heart. Because veins have very thin walls but are usually wider than the arteries carry the same volume of blood but with a lower speed and with much less pressure.

The essential difference between the arterial and venous system is that the first vessels have smooth muscle that allows them to contract in a coordinated manner with the heart to pump blood through them while veins lack muscle in their walls.

Exercise and cardiovascular system

Physical activity helps to strengthen the heart, enabling it to pump blood throughout the body with less effort. Anyone of any age can benefit from daily exercise.

Unless diseases such as respiratory failure, angina or diabetes, you can start exercising at any time suffer. And if they occur, will be made only according to the doctor's recommendations.

Benefits of exercise on the heart

It helps increase the relative levels of "good" cholesterol in the blood.

It helps prevent pooling of blood in the peripheral veins and thus prevents blood clots.

It helps control blood pressure.

It helps maintain a healthy weight.

It helps control blood sugar levels and reduces the incidence of diabetes mellitus, one of the main factors of cardiovascular disease.

Reduces the probability of dying in case of having a first heart attack and help you recover if you have suffered.