Cardiovascular SystemChapter 13

Objectives:1.Identify structures and

functions of the cardiovascular system.

2.Trace the flow of blood through the body.

Coverings of the Heart• Pericardium: (?)1. Visceral (?)pericardium (“epicardium”(?))– Innermost layer– Covers the heart

2. Parietal (?)pericardium– Outer layer of visceral pericardium– Forms inner lining of fibrous pericardium

3. Fibrous (?)pericardium– Dense connective tissue attached to central portion

of diaphragm, posterior of sternum, vertebral column, and large blood vessels attached to heart

Pericardial Cavity

• Space between parietal and visceral pericardium layers

• Filled with serous fluid to reduce friction between the membranes as the heart moves

Wall of the Heart1. Epicardium– Outer layer– Corresponds to visceral pericardium– Protects heart by reducing friction

2. Myocardium– Thick, middle layer– Consists mostly of cardiac muscle tissue that pumps

blood out of the heart chambers3. Endocardium– Inner layer– Epithelium and connective tissue

Heart Chambers & Valves• ????• Four hollow chambers:– Upper chambers = atria (atrium)– Lower chambers = ventricles

• Atria– Thin walls– Receive blood returning to the heart

• Ventricles– Receive blood from the atria– Contract to force blood out of the heart into the

arteries

Heart Chambers & Valves, continued…..

• Left atrium and ventricle are separated from the right atrium and ventricle by a solid, wall-like septum.

• Atrioventricular valve – separates ???– Tricuspid valve

• on the right• “3 cusps”

– Bicuspid valve (“mitral valve”) • on the left• “2 cusps”

– Allows blood to flow ONLY from atrium to ventricular – no backflow

Heart Chambers & Valves, continued…..

• Right atrium receives blood from:– Superior vena cava (???)– Inferior vena cava (???)– Coronary sinus – small vein that drains blood

from the myocardium• Right ventricle– Thinner muscular wall than the left ventricle– Only has to pump blood to the lungs

• Blood leaves the ventricle through the pulmonary valve, and enters the pulmonary trunk, which divides into the left and right pulmonary arteries.

Heart Chambers & Valves, continued…..

• Left atrium receives blood from the lungs through 4 pulmonary veins.

• Blood leaves the left ventricle through the aortic valve, into the aorta.

• Ventricular wall is thicker – has to pump blood to the rest of the body

Sketch & Label the Valves

Label the Exterior Heart