How Does the Blood Circulatory System Work?
The blood circulatory system, also known as the cardiovascular system, delivers oxygen and nutrients to every cell in the human body. Blood vessels( arteries and veins) and heart are the components of the system. The heart pumps blood away through arteries, and veins bring it back to the heart. The cardiovascular system appears like a tree; the trunk the main artery (aorta) divides itself into large arteries, leading to smaller vessels, the smallest forms a network of blood vessels called capillary network. Blood must always flow to uphold life.
Two Kinds of the Circulatory System
There are two different types of blood circulatory system operating in the human body. The systemic circulation is responsible for carrying oxygen and other essential nutrients with blood to organs, tissues, and cells. The pulmonary system is a part of the cardiovascular system, which takes away deoxygenated blood and returns oxygenated blood in the system.
How the System works
Blood circulation starts between the two heartbeats when the heart rests. In expansion, the blood flows from the upper two chambers (atria) to the lower two chambers (ventricles). From ventricles, the blood is supplied in larger arteries, in a stage named the ejection period.
In the systemic circulation, the heart supplies oxygenated blood from the left vertical to the aorta. From there, the blood travels through the large arteries finish up in the capillary network. In the process, the blood carries necessary oxygen and other nutrients and returns the deoxygenated blood into the right atrium and ventricle of the heart. In the process, the blood carries oxygen, vital nutrients, and collects the resident substance and carbon dioxide. The blood moves to those lungs to replace carbon dioxide for oxygen and return to the left atrium. The oxygenated blood flows from the left atrium to the left ventricle and starts systemic circulation again.
The right ventricle pumps the blood low in oxygen content into the pulmonary artery to begin the pulmonary circulation. The artery, which divides itself into smaller arteries and capillaries, the capillaries in the lungs for a fine network around the pulmonary vesicles, which are air sacs, looks like grapes. Carbon dioxide is released from the bloodstream into the air inside the pulmonary vesicles. When we breathe out, carbon dioxide is released from the body. As we breathe in, new oxygen enters into the bloodstream via alveoli, and oxygen content rises in the blood. The oxygenated blood travels from the lungs through pulmonary veins and into the left ventricle. The next heartbeat initiates a new systemic circulation.
The Cardiovascular System
The blood circulatory system, which is also known as the cardiovascular system, delivers oxygen and nutrients to every cell in the human body. The Blood vessels, which are the arteries and veins, along with the heart are the components of this system. The heart pumps blood away via the arteries, and the veins bring it back to the heart. The cardiovascular system when looked at anatomically appears like a tree, where the trunk which is the main artery (aorta) divides itself into large arteries, leading to smaller vessels, the smallest forms a network of blood vessels known as the capillary network. The Blood must always be flowing through our body to uphold life.
Types of Circulatory System
There are basically two different types of blood circulatory systems operating inside the human body. The systemic circulation system is responsible for carrying oxygen and other essential nutrients with blood to organs, tissues, and cells. The pulmonary system, which is a part of the cardiovascular system, takes away deoxygenated blood and returns oxygenated blood in the system. The Heart is the most important organ of the human body to survive and hence we must take proper care to keep it in a good condition.
The Blood circulation starts between the two heartbeats when the heart rests. During expansion, the blood flows from the upper two chambers (atria) to the lower two chambers (ventricles). From the ventricles, the blood is supplied in larger arteries, in a stage that is named the ejection period. The heart is also the center of the circulatory system and pumps blood to the rest of the body, to all the organs and cells. This hollow muscular body of the heart is made up of four chambers, the left and right atriums make the upper two chambers while the left, and right ventricles form the lower two chambers. One way valves are incorporated between chambers to ensure that the blood flow is in the right direction.
Heart of the Circulation System
The heart is the center of the circulatory system and pumps blood to the rest of the body, to all organs and cells. This hollow muscular body is made up of four chambers; left and right atriums make the upper two chambers and left, and right ventricles form the lower two chambers. One way valves are incorporated between chambers to ensure the right direction of blood flow. Two independent networks of blood vessels work together to complete the circulation system, they are pulmonary and systemic. A cluster of cells known as sinus nodes located at the top of the right atrium controls the heartbeat; relaxation and contraction. Electrical signals are emitted from the sinus node, through an electrical conduction system of the heart to direct the muscles to relax or contract.
There are two segments in a heartbeat; the systole and diastole phase. In systole, the ventricles contract and thrust the blood into the aorta or pulmonary artery. The one-way valve situated between the atria and ventricle closes, stopping the blood from flowing backward. In the diastole phase, the valve linking to the atria opens, allowing the ventricle to be filled with blood. The sinus node controls the pace of these two phases.
In an average adult human, around five to six liters of blood are pumped through their bodies. A heart beats around 100,000 times per day, pumping 7,570 liters of blood through 96,560 kilometers of blood vessels. In a mere 20 seconds, the blood covers the entire circulatory system.
The Lymphatic System
The lymphatic system is also a network of vessels that run throughout the body. These vessels do not create a complete circulatory system and are not governed by the heart. This system is an open one, where fluid moves from one direction to limits towards two drainage points into veins, just above the heart. Due to the absence of pressure, lymphatic fluid moves at a slower space than blood. Small lymph capillaries interact with blood capillaries in the interstitial spaces in the tissues. Tissue fluids enter the lymph capillaries and are carried away. The lymph fluids contain a large number of white blood cells.
The lymphatic system has two kinds of lymphoid tissues; the primary lymphoid tissues consist of bone marrow and thymus. There are hematopoietic stem cells (HSC) in the bone marrow which gradually matures into a different type of blood cells and lymphocytes. The secondary lymphatic tissues consist of the spleen, lymph nodes, and diffuse lymphoid tissues; the spleen is an encapsulated formation which filters blood and screens pathogens and antigens. Lymph nodes are found throughout the body, which are bean-shaped. There are clusters of them in the armpits, neck, and in the pelvic region. Swollen lymph nodes indicate your body is fighting an infection. It returns to a standard size when the job is over.
Structure of the Circulatory System
The heart creates pressure, which pushes the blood into arteries; in pressure, the arteries expand, and blood is forced into the smallest capillaries. There are many smooth muscles around veins, which helps the blood to travel through low-pressure veins back to the heart. A minute is taken to complete the blood circulation system from and to heart. Arteries lead to smaller and smaller forming capillaries that provide oxygenated blood to tissues. Veins carry deoxygenated blood, along with other residual substances back to the heart. The waste products are excreted in the lungs and later filtered by the liver and kidney.
Circulatory System Function
The circulatory system functions to provide oxygen and necessary nutrients to cells and remove carbon dioxide from the bloodstream, produced by metabolism. Oxygen is bound to molecules called hemoglobin that are situated at the facade of red blood cells. The cardiovascular system is like an internal highway network, linking all parts of the body through blood vessels, arteries and veins, arterioles and venules, and capillaries. Nutrients like glucose generated from digested carbohydrates are delivered to muscles and organs. Hormones secreted by endocrine are transported by blood vessels to targeted organs; waste products are carried to the lungs and urinary system for expulsion from the body. The cardiovascular system works with the respiratory system to deliver oxygen to cells and remove carbon dioxide.
Conclusion
Exercise for thirty minutes a day, eat healthy balanced food, and maintain a healthy weight to keep your blood pressure robust and optimal. Avoid fast and processed food as they are rich in saturated fat, which often stiffens the walls of the blood vessels. A finely tuned circulatory system carries nutrients, oxygen, electrolytes and hormones throughout the body.
FAQs on Blood Circulatory System Explained: Types, Structure & Functions
1. What are the main components of the human blood circulatory system?
The human blood circulatory system, also known as the cardiovascular system, is primarily composed of three main components that work together to transport substances throughout the body. These are:
The Heart: A muscular organ that acts as a pump to push blood through the blood vessels.
Blood Vessels: A network of tubes that includes arteries, veins, and capillaries, through which blood flows to and from all parts of the body.
Blood: A fluid connective tissue that carries oxygen, nutrients, hormones, and waste products. It consists of plasma, red blood cells, white blood cells, and platelets.
2. What are the different types of blood cells and their functions?
Blood contains several types of cells, each with a specific function crucial for survival:
Red Blood Cells (RBCs or Erythrocytes): These are the most numerous cells in the blood. They contain a protein called hemoglobin, which binds to oxygen in the lungs and transports it to all body tissues.
White Blood Cells (WBCs or Leukocytes): These are the primary cells of the immune system. They protect the body against infectious diseases and foreign invaders by identifying and destroying pathogens.
Platelets (Thrombocytes): These are small, irregular cell fragments that play a vital role in blood clotting. When a blood vessel is injured, platelets gather at the site and form a plug to stop the bleeding.
3. What is the difference between an artery, a vein, and a capillary?
Arteries, veins, and capillaries are the three types of blood vessels, each with a distinct structure and function:
Arteries: They carry oxygenated blood away from the heart (with the exception of the pulmonary artery). They have thick, muscular, and elastic walls to withstand the high pressure of blood being pumped by the heart.
Veins: They carry deoxygenated blood towards the heart (with the exception of the pulmonary veins). Their walls are thinner and less elastic than arteries as the blood pressure is much lower. Most veins contain valves to prevent the backflow of blood.
Capillaries: These are the smallest blood vessels, forming a network between arteries and veins. Their walls are only one-cell thick, which allows for the efficient exchange of oxygen, nutrients, and waste products between the blood and body tissues.
4. How does blood circulate through the different chambers of the human heart?
Blood circulates through the heart's four chambers in a specific sequence. Deoxygenated blood from the body enters the right atrium, then passes through the tricuspid valve into the right ventricle. From the right ventricle, it is pumped to the lungs for oxygenation. The now oxygenated blood returns from the lungs and enters the left atrium. It then flows through the mitral valve into the left ventricle, which is the heart's strongest chamber. Finally, the left ventricle pumps the oxygen-rich blood into the aorta for distribution to the rest of the body.
5. What is the importance of blood plasma in the circulatory system?
Plasma is the light-yellow liquid component of blood that holds the blood cells in suspension. Its importance is immense as it acts as the primary transport medium. It carries not only the blood cells and platelets but also a variety of other essential substances, including nutrients (like glucose and amino acids), hormones, antibodies, and waste products (like carbon dioxide and urea) to and from the body's cells.
6. Why is the human circulatory system referred to as a "double circulation" system?
The human circulatory system is called a double circulation system because blood passes through the heart twice for each complete circuit of the body. This system involves two distinct pathways:
Pulmonary Circulation: Moves deoxygenated blood from the heart to the lungs and brings oxygenated blood back to the heart.
Systemic Circulation: Moves oxygenated blood from the heart to the rest of the body and returns deoxygenated blood back to the heart.
The key importance of this separation is that it prevents the mixing of oxygenated and deoxygenated blood, ensuring a highly efficient supply of oxygen to the body's tissues.
7. What is the difference between systemic and pulmonary circulation?
Systemic and pulmonary circulation are the two circuits of the double circulation system. The main difference lies in their destination and the type of blood they carry from the heart.
Systemic circulation is the pathway where oxygenated blood is pumped from the left ventricle to all parts of the body, delivering oxygen and nutrients. Deoxygenated blood then returns to the right atrium.
Pulmonary circulation is the pathway where deoxygenated blood is pumped from the right ventricle to the lungs. In the lungs, it releases carbon dioxide and picks up oxygen. The newly oxygenated blood then returns to the left atrium.
8. Why do veins have valves whereas arteries generally do not?
The presence of valves in veins is a direct consequence of the pressure differences in the circulatory system. Blood in arteries is under high pressure as it is pumped directly from the heart, so its flow is powerful and unidirectional, making valves unnecessary. In contrast, blood in veins is under much lower pressure, especially in the limbs, and often has to flow against gravity to return to the heart. The valves are crucial in veins because they act as one-way gates, preventing the backward flow of blood between heartbeats.
9. What is blood pressure, and what is the significance of its systolic and diastolic values?
Blood pressure is the force exerted by circulating blood on the walls of the arteries. It is a critical indicator of cardiovascular health and is measured in two numbers:
Systolic Pressure (the top number): This measures the pressure in your arteries when your heart muscle contracts (beats) to pump blood out.
Diastolic Pressure (the bottom number): This measures the pressure in your arteries when your heart muscle is at rest between beats.
These values, typically written as systolic/diastolic (e.g., 120/80 mm Hg), show how hard the heart is working to circulate blood through the body.
10. How does the lymphatic system support the main circulatory system?
The lymphatic system plays a crucial supportive role to the main circulatory system. During circulation, some blood plasma leaks out of the capillaries and into the surrounding tissues; this fluid is called interstitial fluid or lymph. The lymphatic system's primary functions are to collect this excess fluid and return it to the bloodstream, which helps maintain blood volume and prevent tissue swelling (oedema). Additionally, the lymph is filtered through lymph nodes, which are key to the body's immune response.
