# data[].attributes.headline
SEPTUM DIVIDING THE HEART AND LAYERS OF THE HEART WALL

# data[].attributes.subject
SEPTUM DIVIDING THE HEART AND LAYERS OF THE HEART WALL

# data[].attributes.body
Septa (septum plural): interatrial septum and interventricular septum.
Layers of the Heart Wall: endocardium, myocardium, and pericardium (composed of visceral pericardium and parietal).

# data[].attributes.body
There are 4 total. The left and right atriums (upper chambers) & left and right ventricles (lower chambers).

# data[].attributes.body
Tricuspid valve, pulmonary valve, mitral valve, and aortic valve.

# data[].attributes.body
Arteries, veins, and capillaries.