Cardiovascular System

Function: Uses blood to transport oxygen, nutrients, cell wastes, hormones, etc. Force to move blood around body is provided by heart and blood pressure

Structure of the Heart Heart Size – about 14 cm x 9 cm (the size of a fist). Weighs less than a pound Located in the mediastinum (space between lungs, backbone, sternum), between the 2 nd rib and the 5 th intercostal space. The distal end of the heart is called the apex.

Fibrous Pericardium encloses the heart (like a bag) and has 2 layers visceral pericardium (inner) parietal pericardium (outer, attached to diaphragm, sternum and vertebrae)

Pericardial cavity – contains fluid for the heart to float in, reducing friction Wall of the Heart Epicardium – outer layer, reduces friction Myocardium – middle layer, mostly cardiac muscle Endocardium – thin inner lining, within chambers of the heart

Heart Chambers & Valves Heart has 4 chambers: o 2 Atria – thin upper chambers that receive blood returning to the heart through veins.. Right and Left Atrium o 2 Ventricles – thick, muscular lower chambers. Receive blood from the atria above them. Force (pump) blood out of the heart through arteries. Right and left ventricle. o Septum – separates the right and left sides of the heart

Valves of the Heart – allow one-way flow of blood. 4 total 2 Atrioventricular Valves (AV) & 2 Semilunar valves o Left Atrioventricular valve – also called the bicuspid valve or mitral valve. Between left atrium and ventricle o Right Atrioventricular valve – also called the tricuspid valve. Between right atrium and ventricle Aortic Semilunar – or just aortic valve. Between the left ventricle and the aorta Pulmonary Semilunar, or just pulmonary valve. Between the right ventricle and the pulmonary artery

Mitral = bicuspid (left side) Tricuspid (right side) Aortic and Pulmonary are both semilunar valves

Path of Blood Flow

Tainted Love…?

Systemic Circulation – delivers blood to all body cells and carries away waste Pulmonary Circulation – eliminates carbon dioxide and oxygenates blood (lung pathway)

Pulmonary Circulation Your heart is a double pump. Circulation is a double circuit: Pulmonary (lungs only) and systemic (rest of the body) The right side works as the pulmonary circuit pump. It receives oxygen-poor blood from the veins through the superior and inferior vena cava and pumps it through the pulmonary trunk. The pulmonary trunk splits into the right and left pulmonary arteries (only arteries without oxygenated blood), which carry blood to the lungs. Oxygen is picked up in longs and carbon dioxide is unloaded. Oxygen-rich blood drains from the lungs and is returned to the left side of the heart through the four pulmonary veins (only veins with oxygenated blood).

Systemic Circulation Blood returned to the left side of the heart is pumped out of the heart into the aorta Systemic arteries branch to supply all essential body tissues. Oxygen-poor blood circulates from the tissues back to the right atrium via the systemic veins into the superior or inferior vena cava. This systemic circulation supplies the body with oxygen and nutrient rich blood. Left ventricle pumps blood all over body and is thicker and more powerful pump than right.

Check your labels!

Name the valves (#5 is not a valve)

1 Pulmonary Valve 2 Tricuspid Valve 3 Mitral (Bicuspid) Valve 4 Aortic Valve 5 Heart Apex

Heart Actions Cardiac Cycle: One complete heartbeat. The contraction of a heart chamber is called systole The relaxation of a chamber is called diastole.

The cusps (flaps) of the bicuspid and tricuspid valves are anchored to the ventricle walls by fibrous “cords” called chordae tendineae. These attach to the wall by papillary muscles. This prevents the valves from being pushed up into the atria during ventricular systole. Can you identify these parts?

Right Atrium Right Atrioventricular Valve (Tricuspid Valve) Right Ventricle Left Atrium Left Atrioventricular Valve (Mitral Valve) Left Ventricle Papillary Muscle Chordae Tendinae Mitral Valve cusps