Understand Your Heart - Know about Cardiovascular System

 Cardiovascular System

A human being is presumed to be 'alive' by the explicit presence of vital signs and the integrated biological functioning of organ systems. Normal symptoms like heartbeat, respiration and brain activity indicate the live activity of a person and are clinically confirmed by measuring the pulse, blood pressure and respiratory rate along with an assessment using pupillary response and spontaneous movement.

The cardiovascular system is the motional system of the body, through which energy substances are conducted to their utility places, and the metabolites (waste products after consumption of energy) are moved out to appropriate organs from where they are excreted.  The processors of the energy include a liquid tissue, the blood that flows through tubular channels called vessels. The entire circulation is maintained by the central pumping organ called the heart.

Kindly take a look at the image above, which illustrates a closed system of tubes made up of parts mentioned below based on their structural and specific areas of organs connected to each other.

Heart:

It is a muscular organ containing four chambers which pumps blood to various parts of the body. It contains two halves, one acting as a receiving chamber called the atrium and the other acting as a pumping chamber called the ventricle.

Arteries:

Identified as distributing channels, they carry blood away from the heart to the different parts of the body, like branches to a tree. The large arteries are rich in elastic tissue; as the branching progresses, there will be an increase of smooth muscle in their walls. Arterioles are the minute branches and are visible to the naked eye.

Veins:

As the reverse of Arteries, Veins are the draining channels which carry blood from different parts of the body back to the heart. The Veins can be compared to tributaries of a river, small veins (venules) joining to form larger veins, which in turn unite to form greater ones termed venae cavae.

Capillaries:

Between the Arterioles and venules, there exist some microscopic vessels carrying out some networking activities. They intimately connect the tissues for a free exchange of nutrients and metabolites (waste products) across their walls between the blood and the tissue fluid. The metabolites are partly drained by the capillaries and partly by lymphatics (system of vessels). Capillaries are replaced by irregularly shaped blood vessels called sinusoids in certain organs like the liver and Spleen.

Based on their functions, the blood vessels are classified into five groups: 1) distributing vessels, including arteries; 2) resistance vessels, including arterioles and precapillary sphincters; 3) exchange vessels, including capillaries, sinusoids, and postcapillary venules; 4) reservoir (capacitance) vessels, including larger venules and veins; and 5) shunts, including various types of anastomoses (connections between two separate structures).

Blood Circulation:

A. Systemic (greater) circulation:

The blood flows from the left ventricle through various parts of the body to the right atrium. In other words, from the left to the right side of the heart.

B. Pulmonary (lesser) circulation:

The blood flows from the right ventricle through the lungs to the left atrium, which indicates that the blood flow is from the right to the left side of the heart.

C. Portal circulation:

It is a part of systemic circulation, which has the following characteristics. 1) The blood passes through two sets of capillaries before draining into a systemic vein. 2) The vein draining the first capillary network is known as the portal vein, which branches like an artery to form the second set of capillaries or sinusoids. Hepatic, hypophyseal, and renal portal circulations are certain examples of this type.

The above few lines are only to understand the functioning of the heart, and as the detailed study of the parts runs to pages, it has not been mentioned here.

Compiled and published by:

Sethumadhavan Venkatrao

ssssethu@gmail.com

+918838535445/+919962859676

Chennai, Tamil Nadu, India