Double Circulation

Double circulation is a circulatory system where blood passes through the heart twice in one complete circuit. Understanding this gets easier with a double circulation diagram and flowchart. The double circulation mechanism ensures that oxygenated and deoxygenated blood flows in separate pathways within the heart.

In this article, we will study double circulation pathways, mechanisms, and more in detail.

In double circulation, the blood flows twice through the heart in one complete cardiac circuit. Double circulation allows for spearation of oxygenated and deoxygenated blood streams. This allows for a more efficient delivery of oxygen to the body’s tissues. Double circulation is a characteristic feature of mammals and birds. The other type of circulation found in nature is single circulation. Here, the blood travels through the heart only once during each complete circuit. It is common in fishes and birds.

Now let’s discuss double circulation in detail.

The labelled diagram of double circulation is given below:

Also Read: Double Circulation Diagram

Double circulation is a highly effective method of blood flow compared to single circulation. In a double circulatory system, the heart which is the main organ for circulation pumps blood through two distinct pathways:

• Oxygenated Pathway: Oxygen-rich blood returning from the lungs enters the left atrium, flows to the left ventricle (the heart’s strongest chamber), and then out to the body through the aorta, the main artery.
• Deoxygenated Pathway: Blood depleted of oxygen returns from the body to the right atrium. It then flows through the right ventricle and into the lungs via the pulmonary artery for gas exchange.

This separation of oxygenated and deoxygenated blood streams is the defining feature of double circulation.

Pulmonary Circulation

Pulmonary circulation is the path blood takes through the heart and lungs to pick up oxygen. The pathway is given below:

• The left ventricles send oxygenated blood to capillaries via systemic circulation.
• The aorta receives the oxygen-rich blood before distributing it to various body areas.
• The deoxygenated blood, which is high in carbon dioxide, is later collected from various sections of the body through veins and venules.
• Re-oxygenated blood is pushed back into the right atrium and subsequently into the vena cava which is superior.
• The right ventricle would receive blood from the right atrium for circulation i.e, pulmonary circulation after receiving the deoxygenated blood.

Systemic Circulation

Blood circulates from the atrium which is on right to the atrium on the left in the pulmonary circulation. Along this path:

• The right ventricle’s blood is collected by the pulmonary artery and sent to the lungs for oxygenation.
• The oxygenated blood is pushed to the atrium present on the left side following the purification process through the pulmonary vein, which is transported to the left ventricles.
• The oxygenated blood is pumped from the left ventricles to the aorta for circulation which would be systemic.
• The rigorous separation of deoxygenated blood and oxygenated blood would be supported by double circulation. Therefore always a certain amount of Oxygen would be supplied to the body this circulation also increases bodily efficiency. In part because of this, mammals are able to regulate their body temperatures. A third portal system exists in addition to the double circulation to increase circulation effectiveness.

Through blood vessels—the arteries and veins—the blood travels rigidly along a predetermined path. 

The systemic circulatory system delivers oxygen and essential nutrients to body tissues, while also removing waste products like carbon dioxide for elimination. The hepatic portal system is a distinct circulatory loop connecting the digestive system to the liver. Blood from the intestines travels through the hepatic portal vein to the liver for processing before entering the general systemic circulation. Finally, the coronary circulation is a unique network of blood vessels that supplies blood specifically to the heart muscle itself.

Here’s a breakdown of the flow through the four chambers of the human heart:

• Right Atrium: Receives deoxygenated blood from the body through superior and inferior vena cavae.
• Right Ventricle: Pumps deoxygenated blood to the lungs through the pulmonary artery.
• Left Atrium: Receives oxygenated blood from the lungs through the pulmonary vein.
• Left Ventricle: Pumps oxygenated blood to the body through the aorta.

The flow of blood through heart and lungs is better explained with the help of a flowchart.

The advantages of double circulation are:

• Efficient Oxygen Delivery: Ensures that oxygenated and deoxygenated blood do not mix, providing tissues with highly oxygenated blood for more efficient metabolism.
• Higher Blood Pressure: Maintains higher blood pressure in the systemic circuit, allowing blood to be delivered more effectively to all body parts, especially in larger animals.
• Better Regulation: Allows for better regulation and control of blood flow to different parts of the body according to their needs.
• Improved Waste Removal: More efficient removal of carbon dioxide and metabolic wastes from tissues due to effective blood circulation.
• Adaptation to Activity Levels: Supports higher activity levels and endothermy (maintaining constant body temperature) in mammals and birds by providing a consistent and efficient supply of oxygen and nutrients.
• Separate Circuits: The separation of pulmonary (lungs) and systemic (body) circuits allows for specialized functions and adaptations in each system.

The difference between double circulation and single circulation is given below:

In conclusion, the double circulation system is a highly efficient method of blood flow found in mammals and birds. This system allows for the separation of oxygenated and deoxygenated blood, which significantly improves the delivery of oxygen and nutrients to body tissues and the removal of waste products. By maintaining higher blood pressure and providing better regulation of blood flow, double circulation supports higher activity levels and the ability to maintain a constant body temperature. The separation of pulmonary and systemic circuits enables specialized functions, making this circulatory system more effective than single circulation found in fish and some amphibians. Overall, double circulation is a key factor in the high metabolic efficiency and adaptability of complex organisms.

Also Read:

• Diagram of Human Circulatory System
• Human Circulatory System
• Diagram of Blood Vessels
• Body Fluids and Circulation
• Fetal Circulation Diagram
• How is Blood Circulated in the Body?

What is the Double Circulation System Class 10?

The double circulation system in Class 10 refers to the pathway where blood passes twice through the heart in a single complete circuit.

What is the Difference Between Double Circulation and Single Circulation?

The difference between double and single circulation lies in whether blood passes through the heart once (single) or twice (double) during each complete circuit of the body.

What is the Flow of Double Circulation?

The flow of double circulation involves the heart pumping oxygenated blood to the body through the systemic circuit and deoxygenated blood to the lungs through the pulmonary circuit.

What is Oxygenated and Deoxygenated Blood?

Oxygenated blood is rich in oxygen and is pumped from the lungs to the body, while deoxygenated blood is low in oxygen and returns from the body to the heart or lungs for oxygenation.