is the organ that helps supply blood
and oxygen to all parts of the body. It is divided by a partition or septum into two halves, and the halves are in turn divided into four chambers. The heart is situated within the chest cavity and surrounded by a fluid filled sac called the pericardium
. This amazing muscle produces electrical impulses that cause the heart to contract, pumping blood throughout the body. The heart and the circulatory system
together form the cardiovascular system
Heart Anatomy: Chambers
- Atria - upper two chambers of the heart.
- Ventricles - lower two chambers of the heart.
Heart Anatomy: Heart Wall
- Epicardium - the outer layer of the wall of the heart.
- Myocardium - the muscular middle layer of the wall of the heart.
- Endocardium - the inner layer of the heart.
Heart Anatomy: Cardiac Conduction
is the rate at which the heart conducts electrical impulses. The following structures play an important role in causing the heart to contract:
Heart Anatomy: Cardiac Cycle
The Cardiac Cycle
is the sequence of events that occurs when the heart beats. Below are the two phases of the cardiac cycle:
- Diastole Phase - the heart ventricles are relaxed and the heart fills with blood.
- Systole Phase - the ventricles contract and pump blood to the arteries.
Heart Anatomy: Valves
are flap-like structures that allow blood to flow in one direction. Below are the four valves of the heart:
- Aortic Valve - prevents the back flow of blood as it is pumped from the left ventricle to the aorta.
- Mitral Valve - prevents the back flow of blood as it is pumped from the left atrium to the left ventricle.
- Pulmonary Valve - prevents the back flow of blood as it is pumped from the right ventricle to the pulmonary artery.
- Tricuspid Valve - prevents the back flow of blood as it is pumped from the right atrium to the right ventricle.
> Heart Anatomy: Blood Vessels