Cardiovascular system

Introduction: Cardiovascular system includes heart and blood vessels.

Heart pumps blood into the blood vessels.

Blood Vessels circulate the blood throughout the body.

Blood transport nutrients and Oxygen to the tissue and removes carbon dioxide and waste products from the tissue.

The Blood Vessels

The cardiovascular system has three types of blood vessels.

1. Arteries (and arterioles) : carry blood away from the heart.

2. Capillaries: Where nutrients and gas exchange occur.

3. Veins (and venules) : carry blood towards the heart.

Heart : Heart is a muscular organ that pumps blood throughout the circulatory system.

Shaped : Cone shape.

Size : 12cm long

          9 cm width

          6 cm thickness

Weight : Women- 230-280 gm.

               Men -300-340 gm.

Location : The heart lies in the thoracic cavity in the media sternum (the space between the hunga).

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

Structures of heart

1. Layer of heart.

2. Chamber of heart.

3. Valve of heart.

Layer of heart-

The heart wall 

(a) Pericardium  -- Outer layer

(b) Myocardium --Medial layer

(c) Endocardium -- Inner layer 

1.Pericardium: The outermost double walled membrane that surrounds and protects the heart.

It confines the heart to it's position and allows sufficient freedom of movement for contraction .

2. Myocardium : The Myocardium is composed of specialized cardiac muscle found only in the heart.

Middle layer made up, cardiac muscle tissue.

3. Endocardium : This lines the chambers and valves the heart.

It is thin smooth membrane to ensure smooth flow of blood through the heart.

It consists of flattened epithelial cells.

The Chambers of heart

The heart has four Chambers.

        1.  Right Atrium 

        2. Left Atrium 

        3. Right Ventricle

        4. Left Ventricle

1. Right Atrium : The right atrium receives blood from three veins the superior vena cava, Inferior vena cava and coronary sinus.

Blood passes from the right atrium into the right ventricle through a valve that is called the tricuspid valve.

It consists three leaflets of cusps.

The right atrium and left atrium is separated by Intertital septum.

2. Right Ventricle: The right ventricle is thickness.

Blood passes from the right ventricle through the pulmonary valve into a large artery called the pulmonary trunk which divides into right and left pulmonary arteries.

The right ventricle is separated from the left ventricle by the Interventricular septum.

3. Left Atrium : The left atrium is about the same thickness as the right atrium and forms most of the base of the heart.

It receives blood (oxygenated blood) from the lungs through four pulmonary veins.

Blood passes from the left atrium into ventricle the through the Bicuspid (Mitral) valve it is also called the left atrioventricle valve.

4. Left Ventricle : The left ventricle is the thickest chamber of the heart.

Blood passes into the arch of the aorta and descending aorta ( thoracic aorta and abdominal aorta).

Blood passes from the left ventricle through the aortic valve ( Aorta semilunar valve) into the ascending aorta.

Branches of the arch of the aorta and descending aorta carry blood through the body.

Valves.

1.Tricuspid valve: Valve between right atrium and right ventricle.

2. Bicuspid valve : Valve between Lift atrium and left ventricle.

3. Semilunar valve : Valve between Lift ventricle and aorta, right ventricle and pulmonary artery.