The Cardiovascular System: The Heart
The Pulmonary and Systemic Circuits
The right side of the heart is the pulmonary circuit pump.
Pumps blood through the lungs, where CO2 is unloaded and O2 is picked up.
The left side of the heart is the systemic circuit pump.
Pumps blood to the tissues, delivering O2 and nutrients and picking up CO2 and wastes.
Heart Anatomy
Size, Location, and Orientation
The heart is the size of a fist and weighs 250–300 grams.
The heart is found in mediastinum and two-thirds lies left of the midsternal line.
The base is directed toward the right shoulder and the apex points toward the left hip.
Coverings of the Heart
The heart is enclosed in a doubled-walled sac called the pericardium.
Deep to pericardium is the serous pericardium.
The parietal pericardium lines the inside of the pericardium.
The visceral pericardium, or epicardium, covers the surface of the heart.
The right side of the heart is the pulmonary circuit pump.
Pumps blood through the lungs, where CO2 is unloaded and O2 is picked up.
The left side of the heart is the systemic circuit pump.
Pumps blood to the tissues, delivering O2 and nutrients and picking up CO2 and wastes.
Heart Anatomy
Size, Location, and Orientation
The heart is the size of a fist and weighs 250–300 grams.
The heart is found in mediastinum and two-thirds lies left of the midsternal line.
The base is directed toward the right shoulder and the apex points toward the left hip.
Coverings of the Heart
The heart is enclosed in a doubled-walled sac called the pericardium.
Deep to pericardium is the serous pericardium.
The parietal pericardium lines the inside of the pericardium.
The visceral pericardium, or epicardium, covers the surface of the heart.
Layers of the Heart Wall
The myocardium is composed mainly of cardiac muscle and forms the bulk of the heart.
The endocardium lines the chambers of the heart.
The myocardium is composed mainly of cardiac muscle and forms the bulk of the heart.
The endocardium lines the chambers of the heart.
Chambers and Associated Great Vessels
The right and left atria are the receiving chambers of the heart.
The right ventricle pumps blood into the pulmonary trunk; the left ventricle pumps blood into the aorta.
The right and left atria are the receiving chambers of the heart.
The right ventricle pumps blood into the pulmonary trunk; the left ventricle pumps blood into the aorta.
Heart Valves
The tricuspid and bicuspid valves prevent backflow into the atria when the ventricles contract.
When the heart is relaxed the AV valves are open, and when the heart contracts the AV valves close.
The aortic and pulmonary valves are found in the major arteries leaving the heart. They prevent backflow of blood into the ventricles.
When the heart is relaxed the aortic and pulmonary valves are closed, and when the heart contracts they are open.
The tricuspid and bicuspid valves prevent backflow into the atria when the ventricles contract.
When the heart is relaxed the AV valves are open, and when the heart contracts the AV valves close.
The aortic and pulmonary valves are found in the major arteries leaving the heart. They prevent backflow of blood into the ventricles.
When the heart is relaxed the aortic and pulmonary valves are closed, and when the heart contracts they are open.
Pathway of Blood Through the Heart
The right side of the heart pumps blood into the pulmonary circuit; the left side of the heart pumps blood into the systemic circuit
The right side of the heart pumps blood into the pulmonary circuit; the left side of the heart pumps blood into the systemic circuit
Coronary Circulation
The heart receives no nourishment from the blood as it passes through the chamber.
The coronary circulation provides the blood supply for the heart cells.
In a myocardial infarction, there is prolonged coronary blockage that leads to cell death.
The heart receives no nourishment from the blood as it passes through the chamber.
The coronary circulation provides the blood supply for the heart cells.
In a myocardial infarction, there is prolonged coronary blockage that leads to cell death.
