Human Circulatory System - Transportation

All living organisms need few necessary components like air, water, and food for their survival. On our regular basis, we ensure these elements by breathing, drinking and eating. The required elements are transported to our body cells and tissues by the circulatory system.

Let’s learn about the human circulatory system and its components which serve as the transportation system in our body.

Human Circulatory system

A system that circulates every necessary element in the body. In order to circulate necessary components, we require a messenger and messenger requires a pathway to support. Moreover, the human circulatory system works on this principle.


The muscular organ which is located near the chest slightly towards the left in the thoracic region. It is the very crucial organ of our body which works continuously throughout our life. The human heart is divided into four chambers which are involved in the transportation of oxygenated blood and deoxygenated  The upper two chambers are called as atria whereas the lower two chambers are called as ventricles.


The human circulatory system is more advanced than that of other animals like fish, reptiles, etc. In the human body, blood circulates through the heart twice. Hence, circulation in human beings is called double circulation.

Circulation of blood in humans takes places as shown below:

Blood circulation - Human circulatory system

Double Circulation


The fluid connective tissue which plays a vital role in circulating food, hormones, water, air and other necessary products to different parts of the body. Blood flows through a specified set of pathways called blood vessels. The organ which is involved in pumping blood to different body parts is the heart.  Blood cells, blood plasma, proteins, and salts together constitute the human blood. The composition of blood are:

  • Plasma, the fluid part of the blood that is composed of  90%  of water.
  • Blood cells, the solid part of blood.

There are three types of blood cells.

  1. Red blood cells (RBC) / Erythrocytes: They are mainly involved in transporting oxygen, food, and other substances to various parts of the body. These blood cells also function by, removing the waste from the body.
  2. White blood cells (WBC) / Leukocytes: They are specialized in defense. They fight against foreign particles entering the body.
  3. Platelets /Thrombocytes: Platelets help in clotting of blood at the time of wound or cut.

Blood Vessels

Blood vessels are the pathways through which the blood travels from one part to different parts of the body.  Arteries and veins are two types of blood vessels in the circulatory system of the body.

  • Arteries are the blood vessels that transport oxygenated blood from the heart to various parts of the body. They are thick, elastic and are divided into a small network of blood vessels called capillaries.
  • Veins are blood vessels that carry de-oxygenated blood towards the heart from various parts of the body.  They are thin, elastic and are present closer to the surface of the skin. However, pulmonary and umbilical veins are the only veins that carry oxygenated blood.


The human circulatory system consists of another body fluid called lymph. It is also known as tissue fluid. It is a colorless fluid consisting of salts, proteins, water, etc. which transport and circulates digested food and absorbed fat to intercellular spaces in the tissues.

To learn more about the circulatory system, visit Byju’s.

Practise This Question

The two upper chambers of the heart are called the