Basic Anatomy of the Heart
About the heart
The heart is the hardest working muscle in the human body. Located almost in the center
of the chest, the adult human heart is about the size of a fist.
At an average rate of 80 times a minute, the heart beats about 115,000 times in one
day, or about 42 million times in a year. In a 70-year lifetime, an average human
heart will beat more than 2.5 billion times. Even when a person is at rest, the heart
continuously works hard.
The average heart rate for children 10 years and older and adults is 60 to 100 beats
per minute. In a well-trained athlete, the heart rate can be healthy at a rate of
40 to 60 beats per minutes.
How the heart works
The cardiovascular system is made up of the heart and blood vessels. It's responsible
for circulating blood throughout your body to supply the tissues with oxygen and nutrients.
The heart is the muscle that pumps blood filled with oxygen and nutrients through
the blood vessels to the body tissues. It is made up of:
4 chambers (2 atria and 2 ventricles) that receive blue (deoxygenated) blood from
the body and pump out red (oxygen-rich) blood back to it:
Blood vessels, which include a network of arteries and veins that carry blood throughout
4 valves to prevent backward flow of blood:
An electrical system that serves as a natural pacemaker and stimulates contraction
of the heart muscle.