Human Circulatory System- An Overview

Introduction to Human Circulatory System

The human body is a complex machine and requires many cycles to work proficiently. In order to maintain the body’s critical systems and processes, it is crucial to transport vital nutrients from one part to another. 

This transportation job is achieved by the human circulatory system, which circulates essential nutrients and minerals through the body via the blood. The heart’s muscle acts as a pump, pumping blood to the body through an organisation of arteries and veins. Your circulatory system can likewise be characterised as your cardiovascular or vascular system. 

The function of the Human Circulatory System

Let us first understand the critical function of the human circulatory system.

• The primary role is to utilise blood as an agent to circulate and transport vital nutrients, oxygen ,carbon dioxide, hormones and blood cells to and from the various cells in the body. 
• This helps provide nourishment to the cells in the body, thus preparing them to fight diseases. Thus, the body’s various organs, tissues and muscles remain in a healthy and good working condition.
• Additionally, the circulation mechanism also stabilises the body temperature and pH, helps maintain homeostasis. 
• The circulatory system in the human body also contributes to eliminating waste products such as carbon dioxide from respiration, food waste and chemical by-products released by organs.

Elements of the Human Circulatory System –  

• The human circulatory system comprises the heart, blood vessels and blood.
• The human circulatory system courses blood through two cycles – one comprises oxygenated blood and the other comprises deoxygenated blood. This is termed Double Circulation.
• The human heart comprises four chambers – two ventricles and two auricles.
• It has a body-wide organisation of wire-like tubes. These consist of arteries, veins and capillaries.
• Veins move oxygenated blood and supplements to all parts of the human body. It is likewise entrusted with gathering metabolic excreta to be removed from the body.

Did you know that if hypothetically, the veins, capillaries and arteries of the circulatory system in the human body were spread out, they would cover a distance of 1,00,000 kilometres? That is more than double the Earth’s circumference at the Equator.

Organs of the Human Circulatory System

Let us name the organs of the circulatory system. The human circulatory system includes three principal organs. The real circulatory system organs include:

• Heart
• Blood vessels 
• Blood

The Heart

The human heart is a muscular organ situated in the middle of the chest – somewhat to one side of the sternum (breastbone). It sits between your lungs and is encased in a Double circulation walled sac called the pericardium. The pericardium serves to secure the heart and anchor it inside the chest. An adult heart weighs 250-350 g and is often said to be of the size of a fist.

The human heart has four chambers: two upper chambers (the atria) and two lower ones (the ventricles). The right chamber and right ventricle make up the “right heart” and the left chamber and left ventricle make up the “left heart.” A mass of muscle called the septum isolates the different sides of the heart.

The heart functions as the pump in the circulatory system. Thus, it maintains a continuous flow of blood throughout the body.

The Blood Vessels

The vessels are an organisation of pathways. It is through these pathways that blood goes all through the body. The two essential kinds of veins in the body’s circulatory system are arteries and veins.

Arteries

• Arteries are veins that transport oxygenated blood from the heart to different body parts. 
• They are thick, versatile and are isolated into a little organisation of veins called vessels. 
• Pulmonary arteries transport deoxygenated blood to the lungs.

Veins

• Veins are vessels that transport deoxygenated blood towards the heart from different body locations. 
• They are thin and lie near the outer layer of the skin. 

Capillaries

• Capillaries form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins).

Blood

• Blood is the body’s liquid connective tissue, and it forms an essential part of the human circulatory system. 
• Its primary function is to carry supplements, chemicals, minerals and other fundamental nutrients to various body parts. 
• Blood courses through a predefined set of pathways called veins. The organ which is engaged with syphoning blood to various body parts is the heart. 
• ●Platelets, blood plasma, proteins and other minerals (like sodium, potassium and calcium) comprise human blood.

Blood is made of;

Plasma

The liquid composition of the blood, which comprises 90% water.

Red blood cells (RBC)/ Erythrocytes

Red blood cells are predominantly engaged with shipping oxygen, supplements and different substances to different pieces of the body. These blood cells eliminate waste from the body.

White blood cells (WBC)/ Leukocytes

White platelets are particular cells that work as a body’s protection system. They help form immunity by battling off microbes and harmful microorganisms.

Platelets/ Thrombocytes

Platelets are cells that assist in forming clots and prevent bleeding. They are made inside our bone marrow.

Steps of the Human Circulatory System Process

1. First, the right ventricle sends oxygen-poor blood to the lungs via the pulmonary trunk, i.e. the main pulmonary artery.
2. Meanwhile, the blood cells present in the lungs pick up oxygen. This oxygenated blood is transported from the lungs to the heart’s left atrium by the pulmonary veins.
3. Once the oxygenated blood reaches the left atrium, it is then shifted to the left ventricle, which pumps the oxygenated blood out to the rest of the body through arteries.
4. The oxygenated blood deposits nutrients and hormones and collects waste products as it moves through various parts of the body.
5. Thus, this deoxygenated blood rich in carbon dioxide is then returned to the heart via veins.
6. Next, the heart pumps carbon dioxide-rich blood to the lungs. 
7. Finally, the lungs remove the carbon dioxide from the blood received as you exhale. 
8. The process starts all over again.

Conclusion

To summarise, the circulatory system in the human body is a system that delivers oxygen and nutrients while collecting waste from various organs and parts. It comprises the heart, blood and blood vessels. The human circulatory system follows the double circulation process. The blood passes through the heart twice in one cycle; oxygenated blood from the lungs to the body via the heart and deoxygenated blood from the body to the lungs via the heart.