The circulatory system is the biological system that helps circulate blood throughout the body.
The circulatory system is a vital organ system of all vertebrates, which is involved in the transportation of all the essential elements and components, required to be delivered to the various parts of the body.
The circulatory system is commonly known as the cardiovascular system, as it is composed of the heart and other major organs. It is a network system that functions by delivering essential substances such as blood, oxygen and other nutrients to cells, tissues and other organs for basic functions to occur.
Read more: Anatomy of Circulatory System
What is the circulatory system?
The circulatory system is a vast network of organs and blood vessels that functions both by transporting the necessities (nutrients, oxygen and hormones) and removal of wastes (carbon dioxide, ammonia, urea and other nitrogenous wastes) from the different parts of the body. Not only does the circulatory system transport the necessities, but this system also keeps our cells and tissues healthy and alive.
How does the Circulatory System Work
The circulatory system consists of a vast network of organs, which functions by transporting the essential requirements throughout the body. The heart, blood vessels and blood cells are considered the key organs in the circulatory system.
The functioning of the circulatory system begins with the heart, which is found at the centre of the human chest cavity and functions by pumping blood to different parts of the body.
The heart is composed of four different chambers, left and right atriums, which make up the two chambers at the top and the left and right ventricles from the two chambers at the bottom. These chambers are separated by one-way valves. The circulatory system includes the main blood vessels, which are responsible for circulating fresh oxygen and removing carbon dioxide.
Blood is the transport media of the circulatory system, which functions by transporting all the essential requirements, including respiratory gases, digested and absorbed nutrients, and other excretory products.
The pulmonary and systemic systems are two independent networks that work together. There are three different types of circulation that occur regularly in the body:
- Pulmonary circulation carries deoxygenated blood away from the heart and to the lungs.
- Systemic circulation carries oxygenated blood away from the heart and to other parts of the body.
- Coronary circulation carries oxygenated blood to the heart.
The deoxygenated blood is carried by the veins to the right atrium of the heart, which is then pumped through the pulmonary artery and enters the lungs, where the exchange of carbon dioxide and oxygen takes place.
The systemic network of arteries carries oxygen and nutrient-rich blood from the heart to all parts of the body. Veins carry the deoxygenated blood back to the heart. The capillaries are the smallest type of blood vessel, which provide the bridge between the arteries and veins.
Features of the circulatory system
The circulatory system is composed of the heart, arteries, capillaries, veins, blood and blood vessels. The human circulatory system transports oxygenated blood from the lungs to the heart, which is later pumped to different parts of the body via the arteries.
The Heart
The human heart is one of the most important organs of the circulatory system. It is mainly responsible for maintaining and existence of life. The human heart is about the size of two adult hands held together and is found between the lungs and near the centre of the chest.
The human heart is divided into four chambers, namely two ventricles and two atria. The ventricles are the chambers that pump blood and the atrium are the chambers that receive the blood. Among these, the right ventricle and atrium make up the “right portion of the heart”, and the left ventricle and atrium make up the “left portion of the heart.”
The human heart functions continuously throughout the lifespan of an individual without any break. On average, a healthy heart pumps almost 200 million litres of blood and roughly beats 2.5 billion times.
Arteries
Arteries are muscular-walled tubes responsible for transporting oxygenated blood away from the heart to all other parts of the body.
Veins
Veins carry deoxygenated blood to the lungs where they are oxygenated and carried to the heart for circulation.
Also Refer: Difference between Arteries and Veins
Blood
Blood is the only fluid connective tissue, which functions by transporting nutrients, oxygen, minerals, hormones, antibodies, and other essential things required to keep the body healthy. It is one of the most important components of life, which makes up 7 to 8 per cent of our body weight. An average adult possesses around 5 to 6 litres of blood.
There are many cellular structures in the composition of blood. A single drop of blood comprises:
- Blood Plasma.
- Blood Serum.
- Red blood cells or Erythrocytes.
- White blood cells or Leukocytes.
- Blood Platelets or thrombocytes.
Explore more: Blood and its components
Why do we require a circulatory system?
The human body is mainly composed of cells, tissues, organs and organ systems. All these require certain essential elements and components to carry on their metabolic activities to keep our body healthy, which are carried by the circulatory system.
The circulatory system also helps in sustaining all the organ systems and acts as an interface for cell-to-cell interaction.
Combined with the cardiovascular system, the circulatory system engulfs the invading pathogens, maintains the body temperature and also balances the homeostasis among the systems.
Other importance of the circulatory system are:
The Digestive system
The circulatory system is involved in the transportation of digested and absorbed nutrients from the food molecules to each body cell.
Respiratory system
The circulatory system is involved in the transportation of oxygen from the lungs to all parts of the body. Similarly, the carbon dioxide is collected from the different cells and tissues and transported to the lungs, where it is exhaled out into the environment through the nostrils.
Excretory system
Excess amounts of water, salts, nitrogenous wastes, urea and all other wastes produced by the cells, tissues and other organs during its metabolic process are carried to the excretory system, which is thrown out of the body by respective excretory organs.
Endocrine system
The endocrine system includes the specialized glands, which are involved in the production of hormones for the regulation of metabolism, growth and development and other cellular function. The circulatory system is involved in transporting secreted hormones throughout the body or to the target sites.
Disorders of the Circulatory system
The disorders of the circulatory system could be defined as any ailment which affects parts of the circulatory system, including the heart, blood cells, arteries, veins and blood vessels. There are many factors responsible for the disorder of the circulatory system. The main factors are :
- Reduced transportation of blood to the tissue and cells
- Poor supply of oxygen to the tissue and cells
- Hormonal imbalances
- Certain changes in lifestyle
- Lack of nutrients to the tissue and cells
Listed below are the most common disorders of the human circulatory system.
Heart diseases, including stroke, heart attack, hypertension, arteriosclerosis and aneurysm. Other disorders of the human circulatory system are:
- Coronary artery disease
- Heart failure
- Cardiomyopathy
- Heart valve disease
- Arrhythmias
Also Read: Types of heart disease
Frequently Asked Questions on the circulatory system
What are the two circulatory systems?
The two types of circulatory systems are:
- Open circulatory system
- Closed circulatory system
Who discovered the blood circulatory system?
William Harvey, an English physician, was the first person to describe blood circulation in the body.
What is the function of veins in the circulatory system?
Veins are an important part of our circulatory system. Veins carry deoxygenated blood from the various parts of the body toward the heart.
What is a double circulatory system?
Double circulation is a system of circulation where the blood flows through two different routes – one for oxygenated blood and the other for deoxygenated blood. This type of circulation is very effective as the body has a constant supply of oxygenated blood. The majority of mammals, including humans, have a double circulatory system.
How many chambers does the human heart have?
The human heart is divided into four chambers:
- Left Atria.
- Right Atria.
- Left Ventricles.
- Right Ventricles.
Which are the largest vein and the largest artery in the human body.
The largest vein in the human body is the inferior vena cava. It functions by carrying blood from the lower half of the body to the heart.
The largest artery in the human body is the aorta. It functions by carrying blood away from the heart to different parts of the body.
List out the primary risk factors that cause heart failure?
The primary risk factors that cause heart failure include:
- Obesity.
- Smoking.
- High cholesterol.
- High blood pressure.
- Intake of fat-rich food.
Which type of circulatory system is found in humans?
Humans have a closed type of circulatory system
List out the different types of circulation?
There are three types of circulation:
- Pulmonary Circulation
- Systemic Circulation
- Coronary Circulation
What are the causes of high blood pressure?
The following factors could be the major causes of high blood pressure in humans:
- More intake of salty foods.
- Regular intake of too much alcohol.
- Intake of large amounts of fat-rich foods.
What are the various types of blood vessels present in our body?
Blood vessels are classified as follows:
- Veins.
- Arteries.
- Capillaries.
What are the components of blood?
Blood is primarily broken down into the following components:
- Plasma.
- RBC.
- WBC.
- Platelets.
This article concludes an introduction to the circulatory system, its features, importance, functions and disorders of the human circulatory system.
To know more about the human circulatory system, its parts, types, functions and other related topics and important questions, keep visiting our website at BYJU’S Biology.
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