Overview of the Cardiovascular System

The cardiovascular or circulatory system comprises the blood, the heart, and the blood vessels.

Blood is a specialized fluid comprising cells in a liquid extracellular matrix. It transports gases, nutrients, hormones, and cellular waste products throughout the body.

The heart is a muscular pump with four chambers — two atria that receive blood and two ventricles that pump out blood for distribution.

It is connected to a closed circuit of blood vessels, forming an intricate network for blood transport.

This network is divided into two separate circuits: pulmonary and systemic.

The oxygenation occurs in the pulmonary circuit, transporting blood from the heart to the lungs, while systemic circulation distributes oxygenated blood from the heart to the other tissues.

Both these circuits comprise three types of blood vessels: arteries, veins, and capillaries.

The arteries take blood away from the heart, while veins return blood to the heart.

Arteries and veins are connected via microvessels called capillaries, whose thin walls facilitate the exchange of substances between the blood and the interstitial tissue fluid.