Cardiovascular system – Complete story of the heart & blood circulation

Cardiovascular system - Complete story of the heart & blood circulation

The cardiovascular system is the transport system of our body in which cardio refers to heart and vascular refers to blood vessels.

The basic purpose of the cardiovascular system is to circulate the blood to the cell from cells in the body in order to transport nutrients and remove waste.

Hence it is also known as the circulatory system. There are three main components of the cardiovascular system which are as follows:-




The heart, whose pumping action ensures the constant circulation of the blood.

The heart is a roughly cone-shaped hollow muscular organ. It is about 10 cm long and is about the size of the owner’s fist.

It weighs about 225 g in women and is heavier in men (about 310 g). The heart lies in the thoracic cavity in the mediastinum (the space between the lungs).

It lies obliquely, a little more to the left than the right, and presents a base above, and an apex below.

The apex is about 9 cm to the left of the midline at the level of the 5th intercostal space, i.e. a little below the nipple and slightly nearer the midline.

The base extends to the level of the 2nd rib. The heart wall is composed of three layers of tissue pericardium, myocardium, and endocardium.




The blood vessels, which form a lengthy network through which the blood flows.

The blood vessels vary in structure, size and function, and there are several types: arteries, arterioles, capillaries, venules, and veins.

Arteries

  • These blood vessels transport blood away from the heart.
  • They vary considerably in size and their walls consist of three layers of tissue which are listed below:-
    • Tunica adventitia or outer layer of fibrous tissue
    • Tunica a media or middle layer of smooth muscle and elastic tissue.
    • Tunica intima or inner lining of squamous epithelium called endothelium

Arterioles

Arteries branch many times and become smaller until in the arterioles (the smallest arteries) the tunica media consists entirely of smooth muscles and it can control the blood flow to capillary.




Capillaries

The smallest arterioles break up into a number of minute vessels called capillaries.

Venules

The smallest vein is known as venules.

Veins

Veins return blood at low pressure to the heart. The walls of the veins are thinner than arteries but have the same three layers of tissue.

They are thinner because there is less muscle and elastic tissue in the tunica media, as veins carry blood at a lower pressure than arteries.

When cut, the veins collapse while the thicker-walled arteries remain open.

When an artery is cut blood spurts at high pressure while a slower, steady flow of blood escapes from a vein.

The blood itself, blood is a fluid that contains the oxygen and nutrients the body needs and carries the wastes which need to be removed.

Here we trying to present the basic understanding of the cardiovascular system.

The heart has two major circuits within the circulatory pathway.

They worked together in a closed circulatory system. These two pathways are listed below :

The pulmonary circulation

  • In pulmonary circulation, the right side of the heart pumps blood to the lungs (the pulmonary circulation) where gas exchange occurs, i.e. the blood collects oxygen from the air sacs and excess carbon dioxide diffuses into the air sacs for exhalation.





The systemic circulation

  • In the systemic circulation, the left side of the heart pumps blood, which supplies the rest of the body.
  • Here, tissue wastes are passed into the blood for excretion, and body cells extract nutrients and oxygen.

Functions of the cardiovascular system

Blood circulates through a network of vessels throughout the body to provide individual cells with oxygen and nutrients and helps dispose of metabolic wastes. The heart pumps the blood around the blood vessels.

Functions of blood and circulation

  • Circulates OXYGEN and removes Carbon Dioxide.
  • It provides cells with NUTRIENTS.
  • Removes the waste products of metabolism to the excretory organs for disposal.
  • Protects the body against disease and infection.
  • Clotting stops bleeding after an injury.
  • Transports HORMONES to target cells and organs.
  • It helps regulate body temperature.

Cardiovascular function normally declines with age.

The disease of the cardiovascular system is likely to have significant consequences, not only for the heart and blood vessels but also for other body systems.




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