HRTD Medical Institute HRTD Medical Institute
Organic Anatomy of the Cardiovascular System
The cardiovascular system is a closed transport network composed of the heart, a muscular pump, and a vast system of blood vessels (arteries, veins, and capillaries) that circulate blood throughout the body. Its primary function is to deliver oxygen and nutrients to tissues and remove metabolic waste products.
The Heart
The heart is a muscular organ located in the chest cavity, roughly the size of a fist. It is protected by the pericardium, and its wall consists of three layers: the endocardium, the thick muscular myocardium, and the epicardium. The heart is divided into four chambers by a septum: the right atrium and right ventricle, and the left atrium and left ventricle. The atria receive blood, while the ventricles pump blood out. Four valves (tricuspid, pulmonary, mitral, and aortic) ensure blood flows in the correct direction. The heart’s electrical conduction system, starting with the SA node, regulates its rhythmic contractions.
Blood Vessels
Blood vessels are the network that carries blood throughout the body.
- Arteries: Carry blood away from the heart and have thick, elastic walls. The aorta is the largest artery.
- Veins: Carry blood back to the heart, have thinner walls than arteries, and contain valves to prevent backflow. The vena cavae are the largest veins.
- Capillaries: The smallest vessels, with thin walls for exchanging substances between blood and tissues.
Circulatory Loops
The cardiovascular system utilizes three main circulatory loops:
- Pulmonary Circulation: Moves blood between the heart and lungs for oxygen exchange.
- Systemic Circulation: Distributes oxygenated blood from the heart to the rest of the body and returns deoxygenated blood to the heart.
- Coronary Circulation: Provides blood supply specifically to the heart muscle itself.
