Question

Write an essay on the circulation of the heart and blood vessels

Answer 1

Circulation of the heart: It consists of a network of arteries, veins, and capillaries, with the heart pumping blood through it. The main role of the circulation of the heart is to provide essential nutrients, minerals, and hormones to various parts of the body. Alternatively, the circulatory system also plays a significant role in collecting metabolic waste and toxins from the cells and tissues to be purified or expelled from the body.

The features of human circulatory are as follows:

1. The human circulatory system consists of the heart, blood, blood vessels, and lymph.

2. The human circulatory system circulates blood through two routes  (double circulation) – One route for oxygenated blood, another for deoxygenated blood.

3. The human heart consists of four chambers – two ventricles and two auricles.

4. The circulatory system consists of a huge network of blood vessels. These comprise of arteries, veins, and capillaries.

5. The primary function of blood vessels is to transport oxygenated blood and nutrients to all parts of the body. It also works with collecting metabolic wastes from different parts of the body and to be expelled out from the body.

The main organs in the circulatory system:

The human circulatory system organized by 4 main organs that all have specific roles and functions. The vital circulatory system organs are:

1.Heart

2. Blood ( NOTE: Blood is considered a tissue and not an organ)

3. Blood Vessels

4. Lymphatic system.

Circulation Mechanism

The heart is divided into the left and right side by a muscular wall called the septum. The Left and right chamber again divided into four parts. The upper two parts are RIGHT and LEFT Atrium. These chambers receive the blood and push into the lower chambers. These are RIGHT and Left Ventricles. The ventricles pump the blood to the lungs and to the body.

Right artery and right ventricles received the supply of blood from the right coronary artery. It branches into the posterior descending artery, which supplies the lower portion of the left ventricle and back of the septum with blood. These all give blood to all parts of heart muscles.

Both sides of the heart work together. The heart rhythm, causing blood to flow continuously to the heart, lungs, and body to supply oxygen and nutrients to the body cells and to deliver waste products to organs that remove them from the body.

In general, Veins return blood carrying CO2 while arteries usually contain O2 enriched red blood cells.

Working on the Right side of the heart

1. The first blood enters the heart by two large veins, the inferior and superior vena cava, disburden oxygen-poor blood from the body into the right atrium of the heart.

2. As the atrium gets contracts, blood flows from the right atrium into the right ventricle through the open tricuspid valve. The valve in between the right atrium and the right ventricle.

3. When the ventricle is filled whole, the tricuspid valve gets closed. This prevents blood from flowing backward into the atria while the ventricle contracts.

4. As the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it gets oxygenated. Meanwhile, Oxygen-poor or CO2 containing blood goes through the pulmonary artery to the lungs where CO2 is replaced for O_².

Working mechanism on the left side of the heart (Both mechanism operating at the same time) :

1. The pulmonary vein expelled the oxygen-rich blood from the lungs into the left atrium of the heart.

2. As the atrium gets contracts, blood flows from the left atrium into the left ventricle along with the open mitral valve. ( Mitral valve Position: In between the left atrium and left ventricle).

3. When the ventricle is brimful, the mitral valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts.

4. Now ventricle contracts, oxygen-enriched blood leaves the heart through the aortic valve, into the aorta, and to the arteries and finally into veins to complete the blood circulation in the body.

The heart membrane is Endocardium, made up of epithelial cells. It makes the heart chamber silky in which blood cells, platelets, and other substances do not stick in the heart.

Purkinje fibers: Special types of muscles that can help in the transmission of electric signals in heart for contraction and relaxation of muscles for proper guidance to blood flow. The heart also contains collagen fibers to make endocardium elastic.

Sinoatrial node or pacemaker: Clusters of cells present at the right atrium side of the heart, generates electric impulses.

Some important point related to heart structure:

The heart valves work like a water pump. They prevent blood from flowing in the wrong direction.

1. Each valve contains a set of flaps, called leaflets or cusps.

2. The mitral valve: Two leaflets.

3. The tricuspid valve: Three leaflets or cusps.

4. The leaflets are attached to and supported by a ring of tough tissue called the ANNULUS. ( Tissue: Fibrous in nature).

5. The annulus function: It helps to maintain the proper shape of the valve.

6. The leaflets of the mitral and tricuspid valves: Supported by tough, fibrous strings called chordae tendineae.

BLOOD VESSELS:

Blood vessels are a huge network of vessels through which blood travels throughout the body.

Arteries and veins are the two primary types of blood vessels in the circulatory system of the body.

Arteries

Arteries are blood vessels that transport oxygenated blood from the heart to various parts of the body.

Nature: Thick, elastic and are divided into a small network of blood vessels called capillaries.

The exception to this is the pulmonary arteries, which carry deoxygenated blood to the lungs.

Veins

Veins are blood vessels that carry deoxygenated blood towards the heart from various parts of the body.

Nature: Thin, elastic and are present closer to the surface of the skin.

Exceptions: pulmonary and umbilical veins are the only veins that carry oxygenated blood in the entire body.