Update Week: #2

Anatomy of the Heart:

The center of the circulatory system is the heart, which is the main pumping mechanism. The heart is made of muscle and is divided into halves by a muscular wall called septum. Each halve is also divided into two: a top and bottom part which are separated by another muscular wall. Therefore, there are actually four chambers (spaces) inside the heart. Each top chamber is called an atrium and each bottom chamber is called ventricle.

Source 1

Blood can flow from the atria down into the ventricles because there are openings in the walls that separate them. These openings are called valves because they open in one direction, but won't  open in the opposite direction. Valves are also found between the ventricles and the large arteries that carry blood away from the heart. There are four valves in total:

Source 1

Pumping Mechanism of the Heart:

The heart has two muscle states: diastole and systole. Diastole is the state of relaxation and systole is the state of contraction. Below is a video that carefull explains how the pumping mechanism of the heart works:

Source 2

Bibliography:

1) "Pumping Mechanism of the Heart." WizzNotes. Web. 13 Apr. 2015. 

          <http://wizznotes.com/biology/transport/pumping-mechanism-of-the-heart>.

2) "The Heart and Circulation of Blood." The Heart and Circulation of Blood. Web. 14 Apr. 

           2015. <http://lsa.colorado.edu/essence/texts/heart.html>.