Cardiovascular System Overview

Cardiovascular System Components and Function

• The cardiovascular system consists of the heart, blood vessels, and blood.
• The heart is a four-chambered muscular pump that circulates blood throughout the body.
• The right side of the heart pumps deoxygenated blood to the lungs.
• The left side of the heart pumps oxygenated blood to the rest of the body.
• Blood vessels transport blood, including arteries that carry oxygenated blood away from the heart, veins that return deoxygenated blood to the heart, and capillaries that facilitate exchange of oxygen, carbon dioxide, nutrients, and waste between blood and tissues.
• The cardiovascular system's primary function is to deliver oxygen and nutrients to cells and tissues while removing carbon dioxide and waste products.
• It also helps regulate body temperature and maintain fluid balance.

Heart Location, Size, and Position

• The heart is located in the thoracic cavity within the mediastinum, the space between the lungs.
• Its size is roughly comparable to a person's fist, measuring approximately 12 cm long, 8 cm wide, and 6 cm thick.
• The heart is tilted slightly, with its base (top) pointing towards the right shoulder and its apex (bottom) pointing towards the left hip, resting just above the diaphragm.

Heart Apex and Base

• The apex, located at the bottom of the heart, points downward and towards the left. It can be found in the fifth intercostal space near the left midline of the chest.
• The base, situated at the top of the heart, points upward towards the right shoulder at the level of the second rib. This is where major blood vessels enter and exit the heart.

Pericardium

• A double-layered sac that protects the heart
• Parietal pericardium: the outer layer, anchors the heart and prevents over-expansion
• Visceral pericardium: the inner layer, directly covers the heart, reduces friction with a lubricating fluid
• Pericardial cavity: the space between the layers containing fluid to minimize friction during heartbeats

Layers of the Heart Wall

• Epicardium: the outermost layer, also known as the visceral pericardium, protects the heart and reduces friction with surrounding structures
• Myocardium: the thick middle layer, made of muscle tissue, responsible for heart contractions and pumping blood
• Endocardium: the innermost layer, a smooth lining for the heart's chambers and valves, reducing friction as blood flows through the heart

Arteries vs. Veins

• Arteries: carry blood away from the heart
• Veins: carry blood towards the heart

Systemic vs. Pulmonary Circulation

• Pulmonary circulation: circulates blood through the lungs
• Systemic circulation: circulates blood through the rest of the body