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Life Processes

09 Transport In Humans



Air, water and food are essential components for survival and the need for these components is met by ensuring regular breathing, drinking and eating. These elements are transported to our body cells and tissues by the circulatory system.


Human Circulatory System

  • The human circulatory system is one that circulates every necessary element in the body. It works on the principle that in order to circulate necessary components, a messenger is required that in turn requires a pathway to support.
  • There are two types of transport system in human beings:



Blood Circulatory System:

  • The main transport system in human beings (or man) is the ‘blood circulatory system’. The human blood circulatory system consists of two main parts:
  • The heart: the organ which pumps and receives the blood
  • The blood vessels (or tubes) :Through which the blood flows in the body.
  • The blood flows through three types of blood vessels:
  • Arteries
  • Veins
  • Capillaries



Lymphatic system:

It is the system which also helps in the transport of materials in the human body. In human beings, the various substances transport through two liquids called ‘blood’ and ‘lymph’.




The job of heart is to pump blood around our body.

  • Chamber: The hearts has four compartments called ‘chambers’ inside it. The hearts has four compartments called ‘chambers’ inside it. Atria are the upper two chambers of heart. And ventricles are the Lower two chamber of heart.
  • Arteries: Arteries are the thick walled blood vessels which carry blood from the heart to all the part of the body. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
  • Capillaries: The capillaries are thin walled and extremely narrow tubes or blood vessels which connect arteries to veins.
  • Veins: Veins are the thin walled blood vessels which carry blood from all the parts of the body back to the heart. Veins have valves in them which allow the blood in them to flow in only one direction (towards the heart). The valves prevent the backflow of blood in veins. The pulmonary veins carry oxygenated blood from lungs back to the heart.


Working of heart:

  • The human heart is a very crucial organ that works throughout the life of a human being. It is a muscular organ located near the chest slightly towards the left in the thoracic region. Heart is made up of special muscles called cardiac muscles.
  • It also has four chambers namely right atrium, left atrium, right ventricle and left ventricle 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.
  • Right atrium receives deoxygenated blood from body tissues/organs through vena cava.
  • From right atrium blood reaches to right ventricle which pumps deoxygenated blood to lungs through pulmonary artery for oxygenation.
  • After oxygenation the blood from lungs reached to left atrium through pulmonary vein.
  • Oxygenated blood then reaches to left ventricle from where it is pumped to different body parts. The heart beats all the time throughput one’s life.



  • Double circulation is a circulatory system where blood travels twice through the heart in a complete cycle of the body.
  • Double circulation of blood is useful to keep oxygenated and deoxygenated blood from mixing. The human circulatory system is more advanced than that of other animals like fish, reptiles, etc. because of this feature.
  • Circulation of blood in humans takes places as shown below:

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