Hammond Biology- Structure of the Heart

Assuming that your heart beats 70 times each minute of the 70 years that the average person lives, your heart will beat 2,577,204,000 times. Two and a half billion!

Even that is an underestimate! So what is this amazing organ?

Structure of the heart

The adult human heart weighs about a kilogram and has four cavities inside it. These 'chambers' are divided into two at the top called the atria (each is called an atrium) and two at the bottom, called the ventricles.

The diagram shows that the heart is in fact divided neatly in two down its middle so that each side has one atrium and one ventricle. Both the left and right sides of the heart pump blood. The only difference between them is where the blood arrives from and to where…