Circulation system all information

Introduction : Blood vessels from the transport system of the body, through which the nutrients are converted to places where these are utilised and the metabolites (waste products) are converted to appropriate places from where these expelled. The conveying midium is liquid tissue, the blood, which flows in tubular channels called blood vessels. The circulation is maintained by the central pumping organ called the heart.

                      Components

1. Heart: It is a four chambered muscular organ which pumps blood to various parts of the body. Each half of the heart has a receiving chamber called atrium, and a pumping chamber called ventricle. It is the first organ of the body which starts functioning.

2. Arteries : These are distributing channels which carry blood away from the heart. Aorta is the largest artery 

(a) These branch like trees on their way to different parts of the body. These contain oxygenated blood except pulmonary trunk and it's two branches, the pulmonary arteries, which carry deoxygenated blood. During foetal life the umbilical arteries contain deoxygenated blood.

(b) The large arteries are rich in elastic tissue, but as branching progresses there is an ever increasing amount of smooth muscle in their walls 

3. Veins : There are draining channels which carry deoxygenated blood from different parts of the body back to the heart.

4. Capillaries: These are networks of microscope vessels which connect arterioles with the venules.

#.Types of Circulation of blood

Total amount of blood in adult is 4.5--5 litres.

1. Systemic circulation : The blood flows from the left ventricle, through various parts of the body, to the right atrium, from the left to the right side of the heart.

2. Pulmonary circulation : The blood flows from the right ventricle, through the lungs, to the left atrium from the right to the left side of the heart.

3. Portal circulation: It is a part of systemic circulation, which has the following characteristics.

(a) The blood passes through two sets of capillaries before draining into a systemic vein.

(b) The vein draining the first capillary network is known as portal vein which branches like an artery to from the second set of capillaries or sinusoids. Examples : Hepatic portal circulation, Hypothalamo- hypophyseal portal circulation and renal portal circulation.

1. Oxygenated blood

Aorta

Left ventricle

Bicuspid valve

Left atrium

Pulmonary vein

2. Deoxygenated blood

Inferior Vana Cava / Supirior Vana Cava

Right atrium

Tricuspid valve

Right ventricle

Pulmonary trunk

#.Blood Supply of Arteries 

The large arteries ( of more than 1mm diameter) are supplied with blood vessels.

The nutrients vessels called Vasa vasorum, from a sense capillary network in the tunica adventitia, and supply the adventitia and the outer part of tunica media.