A transport system pump

Heart

Receives oxygen-poor blood from body tissues

Right side of the heart

The blood vessels that carry blood to and from the lungs

Pulmonary Circuit

Receives oxygenated blood

Left side of the heart

The blood vessels that carry blood to and from all body tissues

Systemic Circuit

Two receiving chambers of the heart

• Right Atrium
• Left Atrium

Two main pumping chambers of the heart

• Right Ventricle
• Left Ventricle

The medial cavity of the thorax that encloses the heart

Mediastinum

A double-walled sac that encloses the heart

Pericardium

1. Protects the heart
2. Anchors it to surrounding structures
3. Prevents overfilling of the heart with blood

The fibrous pericardium

A thin, slippery, two-layer serous membrane that forms a closed sac around the heart

Serous Pericardium

The three layers of the heart wall

• Epicardium
• Myocardium
• Endocardium

The superficial visceral layer of the serous pericardium

Epicardium

The middle layer that is composed mainly of cardiac muscle and forms the bulk of the heart

Myocardium

The third layer of the heart wall is a glistening white sheet of endothelium resting on a thin connective tissue layer

endocardium

The four chambers of the heart

• two superior atria (Left and Right)
• two inferior ventricles (Left and Right)

Separates the atria from left and right

The interatrial septum

Separates the ventricles from left and right

interventricular septum

Encircles the junction of the atria and ventricles

Coronary sulcus

The right atrium has two basic parts

• A smoothed-walled posterior part
• An anterior portion in which bundles of muscle tissue, called pectinate muscles, form ridges in the walls

The receiving chambers for blood returning to the heart from the circulation

Atria

Blood enter the right atrium via three veins

• Superior vena cava
• Inferior Vena Cava
• Coronary Sinus

The discharging chambers, the actual pumps of the heart

Ventricles

Pumps blood into the pulmonary trunk which routes the blood to the lungs where gas exchange occurs

Right ventricle

Ejects blood into the aorta

Left ventricle

Irregular ridges of muscles that mark the internal walls of the ventricular chambers

trabeculae carneae

The two valves that prevent backflow into the atria when the ventricles contract

Atrioventricular (AV) valves

The right AV valve, which has three flexible cusps

Tricuspid valve

The left AV valve, which has two flexible cusps

Mitral Valve also known as bicuspid valve

Attached to each AV valve flap are tiny white collagen cords which anchor the cusps to the papillary muscles protruding from the ventricular walls

Chordae Tendineae

The two semilunar (SL) valves that guard the bases of the large arteries issuing from the ventricles and prevent backflow into the associated ventricles

• Aortic Valve
• Pulmonary Valve