Circulation of Blood

The circulation of blood is a vital process in which the heart pumps blood throughout the body, delivering oxygen and nutrients to cells and removing waste products like carbon dioxide. This circulatory system is composed of two main circuits: the pulmonary circulation and the systemic circulation. 

1.0Circulatory System Anatomy

• The human circulatory system consists of a network of arteries, veins, and capillaries, with the heart pumping blood through it. 
• Its primary role is to provide essential nutrients, minerals, and hormones to various parts of the body. 
• Alternatively, the circulatory system is also responsible for collecting metabolic waste and toxins from the cells and tissues to be purified or expelled from the body.  

2.0Organs of Circulatory System 

• The human circulatory system comprises 4 main organs that have specific roles and functions. 
• The vital circulatory system organs include:  
• Heart  
• Blood (technically, blood is considered a tissue and not an organ)  
• Blood Vessels  Lymphatic system 

Heart 

• The heart is a muscular organ located in the chest cavity, right between the lungs. 
• It is positioned slightly towards the left in the thoracic region and is enveloped by the pericardium. 
• The human heart is separated into four chambers; namely, two upper chambers called atria (singular: atrium), and two lower chambers called ventricles. 

3.0Types of Circulation

There are two types of circulation of blood taking place in the human heart. 

• Pulmonary Circulation 
• Systemic Circulation

4.0Pulmonary Circulation

• The deoxygenated blood pumped into the pulmonary artery is passed on to the lungs from where the oxygenated blood is carried by the pulmonary veins into the left atrium. 
• This pathway constitutes the pulmonary circulation. 

Significance of Pulmonary Circulation 

• Supply deoxygenated blood to lungs for oxygenation and collect oxygenated blood from lungs.

5.0Systemic Circulation 

The oxygenated blood entering the aorta is carried by a network of arteries, arterioles and capillaries to the tissues from where the deoxygenated blood is collected by a system of venules, veins and vena cava and emptied into the right atrium. This is the systemic circulation. 

Significance of Systemic circulation 

Supply oxygen and nutrients to various parts of the body and collect carbon dioxide and waste materials from different parts of the body. 

6.0Double Circulation 

• Pulmonary circulation and Systemic circulation collectively called "Double circulation".
• In double circulation, blood has to pass through the heart twice once in right part of the heart then goes to lungs for oxygenation and come back to the left side of the heart.

On the basis of supply to the organ circulation is of various types

• For Brain – Cerebral Circulation 
• For Kidneys – Renal Circulation 
• For Heart – Coronary Circulation 
• For liver – Hepatic Circulation
• Coronary Circulation : A special coronary system of blood vessels is present in our body exclusively for the circulation of blood to and from the cardiac musculature.