The Heart
The heart is a muscular pump that creates the powerful driving forces for blood to surge to all parts of the body: this force is adequate enough to open the vessels and as a result the blood is able to pass through and subsequently supply blood to the rest of the body.
The heart is divided into four inner chambers, namely:
- Left Atrium: which receives blood from the lungs.
- Right Atrium: which receives blood from the rest of the body.
- Left Ventricle: which transports oxygenated blood to the rest of the body and picks up carbon dioxide and waste products of metabolism.
- Right Ventricle: which transports blood to the lungs.
These four chambers of the heart are also divided by four valves:
- Tricuspid valve-(three cusps): this is the valve between the right atrium and ventricle.
- Bicuspid valve-(two cusps): this valve is located between the left atrium and ventricle.
- Aortic semi lunar valve: this valve guards the orifice between the left ventricle and the aorta.
- Pulmonary semi lunar valve: this valve safeguards the orifice between the right ventricle and the pulmonary artery.
Main Vessels of the Heart
Arteries
- Aorta
- Right pulmonary trunk artery
- Left pulmonary trunk artery
- Left pulmonary artery
Coronary Arteries
Anterior:
- Right coronary artery
- Marginal artery
- Left coronary artery
- Anterior interventricular artery
- Circumflex artery
Posterior:
- Right coronary artery
- Posterior interventricular artery
- Circumflex artery
The coronary arteries are the sole suppliers of arterial blood to the heart muscle. Approximately 85%of the blood supply is carried by the left coronary artery to the myocardium, and the remainder is carried by the right coronary artery.
The coronary arteries originate just above the aortic valve and segregate into smaller vessels that surround the heart.
Veins:
- Superior vena cava
- Inferior vena cava
- Right pulmonary veins
- Left pulmonary veins
Coronary Veins:
Anterior:
- Great cardiac vein
- Anterior cardiac vein
Posterior:
- Great cardiac vein
- Posterior cardiac vein
- Middle cardiac vein
The four pulmonary veins bring oxygenated blood to the left side of the heart.
Blood enters into the right atrium via the venae cavae and into the left atrium from the pulmonary veins. Blood is then forced into the ventricles when both atria contract. While the atria subsequently relax the ventricles contract. The blood moves upward and forces the atrioventricular valves to close and the semi-lunar valves to open. When both ventricles relax the semi-lunar valves close due to the backflow of blood in the aorta and pulmonary trunk arteries.
Resource: An Online Examination of Human Anatomy and Physiology. GetBodySmart Interactive by ConceptCreators, Inc
