Mls lec

Circulatory system

Is responsible for transporting throughout the body oxygenated blood from the heart and lungs via the arteries

Heart

It is a hollow muscular organ that has four chambers and surrounded by thin, fluid-filled sac called pericardium

•epicardium

•myocardium

•Endocaedium

Layers of the heart

Epicardium

Thin, watery membrane on the outer layer of the heart

Function: covers the heart and is attached to the pericardium

Myocardium

Thick layer of cardiac muscles in the middle of the heart

Function: pumps blood into the arteries by contracting

Endocardium

Thin layer of epithelial cells in the inner layer of the heart

Function: lines the valves and interior chambers

•right atrium

•right ventricle

•left artium

•left ventricle

Chambers of the heart

Right Atrium

Upper right chamber

Function: receives deoxygenated blood from the body

Right ventricle

Lower right chamber

Function: receives the blood from the right atrium and pumps it into the pulmonary artery

Left atrium

Upper left chamber

Function: receives oxygenated blood from the lungs and pumps it into left ventricle

Left ventricle

Lower left chamber

Function: receives blood from the left atrium and pumps it into the aorta

Right AV valve

Tricuspid valve located between the right atrium and right ventricle

Closes as the right ventricle contracts preventing blood from flowing back to the right atrium

Left AV valve

Bicuspid or mitral valve located between the left atrium and the left ventricle

Function: closes as the left ventricle contracts preventing blood from flowing back to the left atrium

Right semilunar valve

Pulmonary or pulmonic valve located at the entrance of the pulmonary artery

Function: closes when the right ventricle relaxes preventing blood from flowing back to the right ventricle

Left semilunar valve

Aortic valve located at the entrance of the aorta

Function: closes when the Left ventricle relaxes preventing blood from flowing back to the left ventricle

Septa

•Interatrial septum

•Interventricular septum

Interatrial septum

Partition that separates the right from the left atria

Interventricular septum

Separates the right and the left ventricles

Coronary circulation

The heart receives blood supply through the left and right coronary arteries, and the coronary veins return the oxygen-depleted blood from the heart muscle back to the heart.

Heart function

It is composed of the left and right coronary arteries and coronary veins