Venous Return

The heart is one of the most crucial organs responsible for sustaining life. The heart is the pumping organ of the body. It pumps blood all the time. It helps in transporting blood to all the parts of the body. The heart pumps blood through the set of connections between veins and arteries. Throughout a person’s lifespan, the functioning of the heart is essential. Besides humans, most animals also have a heart, although their functioning is different.

The process starts with a heartbeat production to the commencement of the upcoming beat. It mainly includes systole, intervening pause, and diastole. The heart rate determines the occurrence of the entire cardiac cycle indicated naturally as beats every minute are called the cardiac cycle. In this study material, we are going through the Venous Return formula, an essential cardiac cycle phase.  

Introduction to Cardiac Cycle 

In simple terms, the cardiac cycle can be defined as the sequence of events in which the heartbeats. The heart rate determines the occurrence of the entire cardiac cycle indicated naturally as beats every minute. The process starts with the beginning of a heartbeat and ends at the beginning of another one. It mainly includes systole, intervening pause, and diastole. The entire cardiac cycle begins at the fourth gestational week. This is the time when the heart first starts to beat the foetus. 

There are mainly three stages in a single cardiac cycle, systole, intervening pause, and diastole. A healthy heart in the human body beats 72 times in a minute, which means that in 60 seconds, 72 cardiac cycles take place. One cardiac cycle lasts for around 0.8 seconds, which involves relaxation and contraction of ventricles and atria. 

What is Venous Return? 

Venous Return can be described as how the blood flows back to the heart. The Venous Return typically limits cardiac output. Under the steady-state conditions, the Venous Return is the same as the cardiac output when averaged over time as the cardiovascular system is simply a closed loop. Else, the blood will start accumulating in pulmonary or systemic conditions. Although both the venous return and cardiac output are independent, both are closely dependent on one another. The entire body’s circulatory system comprises two circulations called the systemic and pulmonary. These are located between the left ventricle (LV) and right ventricle (RV). 

Factors affecting the Venous Return 

Several factors directly or indirectly affect the entire venous return mechanism. These are as follows – 

• Musculovenous pump
• Decreased venous capacitance
• Respiratory pump
• Vena cava compression
• Gravity
• Pumping action of the heart

The Human Circulatory System

Circulation is the process by which fluids are transported into the body. It is one of the vital organ systems in human beings. The components that make up the circulatory system are blood, heart, and blood vessels.

Heart: The heart is the pumping organ of the body. It pumps blood all the time. It helps in transporting blood to all the parts of the body. Some of its chief characteristics are:

• The heart is present on the left side of the chest cavity.
• The heart is sized almost as big as your fist.

Blood: It is the fluid or liquid that flows throughout our body. It flows through the blood vessels. Blood is composed of various components such as Red blood cells or RBCs, White blood cells or WBCs, and Platelets. Blood flows through the veins in our body. Some of its essential functions are as follows:

• It helps transport food from the small intestine to other organs of the body.
• It helps transport oxygen from the lungs to the other parts of the human body.
• It also substitutes waste that is to be removed from the body.   

Blood vessels are the network of hollow tubes such as pipes that consist of the blood and carry it from one part of the body to another. This network of blood vessels is scattered all over the body. These vessels are responsible for carrying blood in both directions, including from the heart to different body parts and from different parts of the body to the heart. The two types of blood vessels present in the human body are veins and arteries. 

• Arteries: They help carry blood rich in oxygen from the heart to all parts of the body. The blood flows at high speed and pressure through the arteries. This results in thick elastic walls for the arteries.
• Veins: These are a type of blood vessel that helps carry blood that is carbon dioxide-rich from the body’s organs. They take it back to the heart. The veins have thin walls. They have valves that direct the blood towards the heart. Except for the pulmonary vein, every vein in the body has impure blood.

Conclusion 

With this, we come to the end of the topic Venous Return in Biology. All organisms on earth survive on food, water, minerals, and oxygen. Life is impossible if all these factors do not come into play. The heart is one of the most crucial organs responsible for sustaining life. The heart is the pumping organ of the body. It pumps blood all the time. It helps in transporting blood to all the parts of the body. Venous Return can be described as how the blood flows back to the heart. The Venous Return typically limits cardiac output. Under steady-state conditions, the Venous Return is the same as the cardiac output. In the end, we also discussed the human circulatory system in humans. We hope the topic Venous Return formula in Biology is clear to everyone.