Heart Chambers and Blood Flow

Study Notes

Heart Chambers and Valves

The heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers).
The right atrium receives deoxygenated blood from the body.
The right ventricle pumps deoxygenated blood to the lungs.
The left atrium receives oxygenated blood from the lungs.
The left ventricle pumps oxygenated blood to the body.
Atrioventricular (AV) valves (tricuspid and mitral/bicuspid) prevent backflow between the atria and ventricles.
Semilunar valves (pulmonary and aortic) prevent backflow from the ventricles into the pulmonary artery and aorta, respectively.

Blood Flow Through the Heart

Deoxygenated blood enters the right atrium from the superior and inferior vena cava.
Blood flows from the right atrium to the right ventricle through the tricuspid valve.
The right ventricle pumps blood to the lungs through the pulmonary valve and pulmonary artery.
Oxygenated blood returns from the lungs to the left atrium via the pulmonary veins.
Blood flows from the left atrium to the left ventricle through the mitral valve.
The left ventricle pumps oxygenated blood to the body through the aortic valve and aorta.

Heart Valves

Tricuspid valve: located between the right atrium and right ventricle, with three cusps.
Mitral (bicuspid) valve: located between the left atrium and left ventricle, with two cusps.
Pulmonary valve: located between the right ventricle and the pulmonary artery, with three cusps.
Aortic valve: located between the left ventricle and the aorta, with three cusps.

Cardiac Muscle

The heart is composed of cardiac muscle tissue, which is unique and specialized.
Cardiac muscle cells are interconnected by intercalated discs, allowing for rapid transmission of electrical signals throughout the heart.
Cardiac muscle is involuntary, meaning it contracts and relaxes automatically without conscious control.
Cardiac muscle cells are striated, like skeletal muscle cells.

Conduction System

The heart's electrical conduction system initiates and coordinates the contractions of the heart muscle.
The sinoatrial (SA) node, located in the right atrium, is the pacemaker of the heart and initiates the electrical impulses.
The atrioventricular (AV) node, located in the interatrial septum, delays the impulse to allow the atria to contract completely before the ventricles contract.
The bundle of His and Purkinje fibers conduct the electrical impulses throughout the ventricles, ensuring coordinated ventricular contraction.
The electrical activity of the heart can be recorded as an electrocardiogram (ECG).

Coronary Arteries and Veins

Coronary arteries supply blood to the heart muscle itself.
The right coronary artery and the left coronary artery branch off the aorta and supply blood to the heart muscle.
Coronary veins collect deoxygenated blood from the heart muscle and return it to the right atrium.
Blockage of coronary arteries can lead to myocardial infarction (heart attack).

Anatomy of Heart Location

The heart is located in the mediastinum, between the lungs, behind the sternum.
It is slightly tilted, with the apex (tip) pointing towards the left hip.
The heart is enclosed by a protective sac called the pericardium.

Heart Sounds

Heart sounds are produced by the closing of the heart valves.
The first heart sound (S1) is caused by the closure of the AV valves.
The second heart sound (S2) is caused by the closure of the semilunar valves.
Abnormal heart sounds (murmurs) can indicate problems with the heart valves or other structures.

Description

Explore the anatomy of the heart, including its four chambers and valves. Understand how blood flows through the heart, starting from deoxygenated blood entering the right atrium to oxygenated blood being pumped into the body. This quiz will test your knowledge of cardiovascular physiology.