The Circulatory System & The Heart
What is the Circulatory System?
Overview of the Circulatory System
- The circulatory system, also known as the cardiovascular system, consists of a group of organs working together to transport substances throughout the body.
- Key components include the heart, blood vessels, and blood, which collectively facilitate the movement of oxygen, nutrients, cells, and waste products.
Double Circulatory System Explained
- Mammals possess a double circulatory system featuring two distinct circuits: the pulmonary circuit (heart to lungs) and systemic circuit (heart to body tissues).
- Blood continuously cycles through these circuits: pumped from the heart to lungs for oxygenation and then distributed to body tissues before returning to the heart.
Anatomy of the Heart
Structure and Function
- The heart functions as a muscular pump with four chambers: two atria (top) and two ventricles (bottom). Valves between them ensure unidirectional blood flow.
- It's crucial to note that when identifying left and right sides on diagrams, they correspond to an observer's perspective rather than our own. This can lead to confusion in labeling.
Chamber Details
- The right atrium receives deoxygenated blood from the body via the vena cava; it then pumps this blood into the right ventricle.
- The left ventricle has a thicker muscular wall compared to the right ventricle because it must pump blood throughout the entire body rather than just to nearby lungs.
Blood Vessels Connected to the Heart
Pathway of Blood Flow
- Blood enters through the vena cava into the right atrium, moves into the right ventricle, and is then sent via pulmonary artery to be oxygenated in lungs.
- Oxygen-rich blood returns through pulmonary veins into left atrium, flows down into left ventricle, and is pumped out through aorta for distribution across body tissues.
Importance of Coronary Arteries
- The heart muscle requires its own supply of oxygenated blood provided by coronary arteries branching off from aorta; these are essential for maintaining cardiac function.
- Blockages in coronary arteries can lead to serious conditions such as coronary artery disease or heart attacks if not addressed promptly.