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There are 2 septa separating the 4 chambers of the heart: interatrial septum and interventricular septum.
Interatrial septum: separates the two upper chambers, atria.
Interventricular septum: lies between the two lower chambers, ventricles.
There are 3 layers of heart walls: the endocardium, the myocardium and the pericardium.
Endocardium: lines the interior of the heart and heart valves.
Myocardium: the middle, muscular layer of the heart wall and is the thickest layer.
Pericardium: a fibrous and membranous sac that surrounds the heart. Composed of 2 layers: the visceral pericardium and the parietal pericardium.

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The heart consists of 4 chambers: Right Atrium, Left Atrium, Right Ventricle and Left Ventricle.
Atrium: one of two upper chambers of the heart.
Ventricle: one of two lower chambers of the heart.

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There are 4 valves located inside of the heart: Mitral Valve, Aortic Valve, Tricuspid Valve and Pulmonary Valve.
Mitral Valve: is the valve between the left atrium and the left ventricle.
Aortic Valve: closes to prevent return of aortic blood to the left ventricle.
Tricuspid Valve: is located between the right atrium and the right ventricle.
Pulmonary Valve: is the valve positioned between the right ventricle and the pulmonary artery.

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There are 3 types of blood vessels in the body: Arteries, Veins and Capillaries.
Arteries: are large blood vessels that carry blood away from the heart.
Veins: conduct blood, that has given up most of its oxygen, toward the heart from the tissues.
Capillaries: carry nutrient-rich, oxygenated blood from the arteries and arterioles to the body cells