Anatomy, Function, and Pathophysiology
I. Introduction
The cardiovascular system is essential for the transportation
of nutrients, gases, and waste products throughout the body. It
consists of the heart, blood vessels, and blood, working together to
maintain homeostasis. Understanding the anatomy and physiology
of the cardiovascular system is fundamental in the medical and
biological sciences. This lesson will provide a detailed examination
of the cardiovascular system, its functions, and common
pathophysiological conditions.
II. Anatomy of the Cardiovascular System
1. The Heart
○ The heart is a muscular organ located in the thoracic
cavity, slightly to the left of the midline. It consists of
four chambers:
■ Atria: The two upper chambers (left and right
atria) receive blood returning to the heart.
■ Ventricles: The two lower chambers (left and right
ventricles) pump blood out of the heart to the lungs
and the rest of the body.
, ○ Layers of the Heart Wall:
■ Endocardium: The inner lining of the heart.
■ Myocardium: The thick, muscular middle layer
responsible for the heart's pumping action.
■ Epicardium: The outermost layer of the heart.
○ Valves of the Heart:
■ Atrioventricular (AV) Valves: These include the
tricuspid valve (right side) and the mitral valve (left
side), which prevent backflow of blood from the
ventricles into the atria.
■ Semilunar Valves: The pulmonary valve and aortic
valve prevent backflow into the ventricles after
blood is pumped out of the heart.
2. The Blood Vessels
○ Arteries: Carry oxygenated blood away from the heart
(except for the pulmonary artery). Major arteries include
the aorta, carotid arteries, and femoral arteries.
○ Veins: Return deoxygenated blood to the heart. Major
veins include the superior and inferior vena cava.
○ Capillaries: Microscopic blood vessels where gas
exchange occurs between blood and tissues.
3. The Blood
○ Blood is composed of plasma (55%) and formed
elements (45%), which include:
■ Red Blood Cells (RBCs): Transport oxygen using
hemoglobin.