In the previous article, we talked about different body system and their major organs and respective functions. In this article, we will see the anatomy of the heart, working, and functions or CardioVascular (Heart) Circulation System.Blood enters the heart on the right side through two main veins: the superior vena cava and inferior vena cava.
|Fig. Cardiovascular Circulation|
Superior vena cava brings blood from the body’s upper parts like head, arms, etc.
Inferior vena cava brings blood from the body’s organs and lower body parts below the heart.
Coronary Sinus vein empties blood into the right atrium.
All three veins empty blood into the right atrium. When the right atrium is full, it contracts and forces blood through the tricuspid valve into the right ventricle. When ventricular pressure exceeds
the atrial pressure, the tricuspid valve closes and the pressure in the ventricle forces the semilunar pulmonary valve to open, which then pumps the blood into the lungs with the pulmonary artery.
Leading to lungs, pulmonary artery divides into two parts toward the left and right lungs. This artery divides into many smaller arteries with smaller cross-sections. In alveoli, an exchange of oxygen and carbon dioxide takes place. The impure blood takes oxygen and gives up carbon dioxide. Now, all the small arteries combine to form bigger veins and takes oxygenated blood to the left atrium.
When the left atrium is full, it contracts and forces blood through the mitral valve or bicuspid valve into the left ventricle. When the ventricular pressure exceeds the atrial pressure, the bicuspid valve closes and the pressure in the ventricle forces the aortic valve to open, which then pumps the oxygenated blood to different body parts with aorta artery. The heart diagram is shown below.
Atrium and Ventricles are synchronised when to contract or dilate. Everything is synchronised with the help of pacing function of the heart. The electrical impulses are generated inside the heart. We have discussed it in Cardiac Conduction System.
The heart pumping cycle is divided into two major parts i.e. Systole and Diastole.
Systole is the period of contraction of the heart muscles, specifically the ventricular muscles when blood is pumped into the pulmonary artery and aorta.
Diastole is the period of dilation of the heart cavities as they fill the blood.