A circulatory path is a path taken by the blood, wherein it travels throughout the different organs of the body through arteries and veins. In humans, it is a closed circulatory system that exists, as blood flows in closed blood vessels. The circulatory system is responsible for the transport of gases, nutrients, waste products etc.
Double circulation is the most efficient way of circulation. Here, in humans, the four-chambered heart, arteries, veins, and capillaries all have a vital role to play. Blood gets pumped out of the heart. This blood goes to different organs and then blood again comes back to the heart. All this happens in a very systematic way through the different arteries and veins carrying oxygenated and deoxygenated blood.
In double circulation, there are two pathways in which blood flows. They are:
- Pulmonary pathway
- Systemic pathway.
The pulmonary circulation or pathway carries the deoxygenated blood from the right side of the heart to the lungs. Exchange of oxygen and carbon dioxide takes place in the lungs and the blood is now oxygenated (with oxygen).
Through the systemic circulation, oxygenated blood travels from the left side of the heart to the other areas of the body. At various organ sites, exchange of gases, nutrients, and waste through lymph occurs. This deoxygenated blood again goes back to the right side of the heart.
The pulmonary circuit and the systemic circuit work together. This ensures that deoxygenated blood goes to the lungs through the pulmonary artery while the oxygenated blood from the aorta reaches the different organs and tissues.