Objective: Describe the double circulation in terms of circulation to the lungs and circulation to the body.
The human circulatory system is a double circulation system, meaning that blood passes through the heart twice in each complete circuit of the body. This system is highly efficient, ensuring that oxygenated and deoxygenated blood are kept separate and delivered to the correct parts of the body.
Pulmonary Circulation: Circulation to the Lungs
Pulmonary circulation is the pathway of blood from the heart to the lungs and back. Its main function is to oxygenate the blood.
Deoxygenated blood from the right ventricle of the heart enters the pulmonary artery.
The pulmonary artery branches into the pulmonary arteries, which carry the blood to the lungs.
In the lungs, carbon dioxide is released from the blood and oxygen is absorbed.
Oxygenated blood then travels from the pulmonary capillaries to the pulmonary veins.
The pulmonary veins carry the oxygenated blood back to the left atrium of the heart.
Systemic Circulation: Circulation to the Body
Systemic circulation is the pathway of blood from the heart to the rest of the body and back. Its main function is to deliver oxygen and nutrients to the body's tissues and remove waste products.
Oxygenated blood from the left atrium passes into the left ventricle.
The left ventricle pumps the oxygenated blood into the aorta, the main artery in the body.
The aorta branches into smaller arteries, which carry blood to all parts of the body.
Arteries then lead to arterioles and finally to capillaries, where oxygen and nutrients are delivered to the body's cells and waste products are collected.
Deoxygenated blood from the capillaries enters venules, which merge to form larger veins.
Veins carry the deoxygenated blood back to the right atrium of the heart.
Summary of Double Circulation
The double circulation system consists of two separate circuits: pulmonary and systemic. The pulmonary circuit handles the blood's journey to the lungs for oxygenation, while the systemic circuit distributes the oxygenated blood to the rest of the body.
Circuit
Starting Point
Destination
Main Function
Pulmonary
Right Ventricle
Lungs
Oxygenation of blood
Systemic
Left Ventricle
Rest of the body
Delivery of oxygen and nutrients to tissues
Suggested diagram: A diagram illustrating the pulmonary and systemic circuits of double circulation, showing the heart, lungs, and the distribution of blood throughout the body.