Human Circulatory System

The Human Circulatory system is a network of blood vessels, arteries, veins and capillaries that circulate blood to and from the heart. Its main purpose is to carry essential nutrients, hormones and oxygen to other parts of the body and eliminate the waste toxins like carbon dioxide and others. Blood is carried to the heart through arteries while it is carried away from the heart through veins. But it has some exceptions like pulmonary artery and vein, which has the opposite work functionality.

Working of Human Circulatory System

The Human circulatory system works with the help of blood vessels which work in coordination with the heart and the lungs to keep the human body healthy and functioning by continuously circulating the blood throughout the body. Pulmonary circulation carries the blood between the heart and the lungs, so it transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. Systemic circulation moves blood between the heart and the rest of the body, therefore it sends oxygenated blood to the cells and returns the deoxygenated blood to the heart.

• The right ventricle of the heart sends deoxygenated blood to the lungs through the pulmonary trunk
• The blood cells pick up fresh oxygen from the lungs and travel back through the pulmonary veins to the left atrium of the heart
• The left atrium then sends the newly oxygenated blood to the left ventricle which pumps out blood to the rest of the body
• The blood moves through the arteries and drops off essential nutrients and hormones to various organs and simultaneously collects waste products
• Now the deoxygenated blood is carried through the veins back to heart which then sends the blood back to the lungs
• This cycle repeats with every heartbeat

Parts of Human Circulatory System

• Heart
• Blood vessels
• Blood 

Heart

The heart is an organ situated between the lungs slightly towards the left of the chest. It has four chambers- two on the top(atrium) and two on the bottom(ventricle).

The top chambers are called the left atrium and the right atrium. Their function is to receive the blood entering the heart.

The bottom chambers are called the left ventricle and the right ventricle. Their role is to carry blood out of the heart. While the left ventricle pumps blood out to the lungs, the right ventricle pumps blood to the rest of the body.

Blood vessels

Blood vessels are channels through which blood flows within the human body. The types of blood vessels are:

• Arteries
• Veins 
• Capillaries

Arteries

Arteries are the vessels which carry blood high in oxygen (oxygenated) away from the heart to the rest of the body(exception is Pulmonary artery). They are muscular vessels which are rough from the outside but have a smooth interior due to the presence of epithelial cells. This helps the blood to flow easily. The Aorta is the largest artery of the body.

Veins

Veins are the vessels which carry blood low in oxygen (deoxygenated) towards the heart(exception is Pulmonary vein). There are two major veins that carry deoxygenated blood to the heart:

• From the upper body blood is carried by the superior vena cava
• From the lower body blood is carried by the inferior vena cava

The veins are weaker and thinner than the arteries. They contain valves to transport the blood from the lower body without it flowing backward due to gravity.

Capillaries

Capillaries are the vessels which connect the small arteries and veins. This is where the actual exchange of oxygen and waste happens. The walls of capillaries are thin so as to allow easy exchange of nutrients and waste among the cells.

Blood

Blood is the body’s fluid tissue, and it forms a significant part of the human cardiovascular system. Its main operation is to flow in nutrients, hormones, minerals, and different essential elements to different parts of the body. Blood flows through a nominative set of pathways known as blood vessels. The organ that is concerned with pumping blood to different body parts is the heart. Blood cells, plasma, proteins, and different mineral parts (such as Na, metallic element, and calcium) represent human blood.

Blood consists of:

-Plasma – the fluid is a part of the blood and consists of ninety percent of water.
-Red blood cells, white blood cells, and platelets represent the solid part of blood.

Types of Blood Cells

It consists of 3 sorts of blood cells, namely:

Red blood cells (RBC) / Erythrocytes

Red blood cells are primarily concerned with transporting chemical elements, nutrients, and different substances to numerous components of the body. These blood cells additionally take away waste from the body.

White blood cells (WBC) / Leucocytes
White blood cells are specialised cells that operate as a body’s weaponry. They supply immunity by averting pathogens and harmful microorganisms.

Platelets / Thrombocytes
Platelets are cells that facilitate making clots and stop wounds. They act on the location of an injury or a wound.

Conclusion

Combined with the circulatory system, the vascular system helps to fight down a malady, helps the body maintain a standard blood heat, and provides the proper balance for the body to attain a physiological state or a state of stability among all its systems.