What is
The Circulatory System?
The circulatory system is an organ system that moves nutrients, gases, and wastes to and from cells, helps fight diseases and helps stabilize body temperature.
The main components of the human circulatory system are the heart, the blood, and the blood vessels.
An average adult contains five to six quarts of blood, which consists of plasma and three types of cells or cell fragments: red blood cells, white blood cells and platelets.
Furthermore, these components can either belong to the systemic circulation and the pulmonary circulation.
The systemic circulation is the main part of the circulatory system, while the pulmonary system oxygenates the blood.
How does the
Heart
Play Its Role?
The heart is a muscular organ responsible for pumping blood through the blood vessels to other parts of the body.
The heart is composed of cardiac muscle, an involuntary muscle tissue which is found only within this organ.
In the human body, the heart is usually situated in the middle of the thorax with the largest part of the heart slightly offset to the left.
Therefore, the left lung is smaller than the right lung because the heart occupies more of the left hemi thorax.
What do the
Ventricles do?
During the normal cardiac cycle, the right ventricle receives deoxygenated blood as the right atrium contracts. During this process the pulmonary valve is closed, allowing the right ventricle to fill. Once both ventricles are full, they contract. As the right ventricle contracts, the tricuspid valve closes and the pulmonary valve opens. The closure of the tricuspid valve prevents blood from returning to the right atrium, and the opening of the pulmonary valve allows the blood to flow into the pulmonary artery toward the lungs for oxygenation of the blood
The right and left ventricles contract simultaneously; however, because the right ventricle is thinner than the left, it produces a lower pressure than the left when contracting. This lower pressure is sufficient to pump the deoxygenated blood the short distance to the lungs.
The lower left chamber of the heart. During the normal cardiac cycle, the left ventricle receives oxygenated blood through the mistral valve from the left atrium as it contracts. At the same time, the aortic valve leading to the aorta is closed, allowing the ventricle to fill with blood. Once both ventricles are full, they contract. As the left ventricle contracts, the mistral valve closes and the aortic valve opens. The closure of the mistral valve prevents blood from returning to the left atrium, and the opening of the aortic valve allows the blood to flow into the aorta and from there throughout the body.
The left and right ventricles contract simultaneously; however, because the left ventricle is thicker than the right, it produces a higher pressure than the right when contracting. This higher pressure is necessary to pump the oxygenated blood throughout the body.
The left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle.
The right atrium is also one of four chambers in the human heart. It receives de-oxygenated blood from the superior and inferior vena cavae and the coronary sinus, and pumps it into the right ventricle through the tricuspid valve.
What does
Blood do?
Blood is a specialized bodily fluid (technically a tissue) that is composed of a liquid called blood plasma and blood cells suspended within the plasma.
The blood cells present in blood are red blood cells, white blood cells and platelets.
Plasma is predominantly water containing dissolved proteins, salts and many other substances; and makes up about 55% of blood by volume.
Humans have red blood, which is bright red when oxygenated, due to hemoglobin.
By far the most abundant cells in blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates transportation of oxygen by reversibly binding to this respiratory gas and greatly increasing its solubility in blood.
In contrast, carbon dioxide is almost entirely transported extracellularly dissolved in plasma.
White blood cells help to resist infections and parasites, and platelets are important in the clotting of blood. But these are not limited to blood only; they occur elsewhere in the body as well, most notably in the spleen, liver, and lymph glands.
