Overview
This lecture covers the structure and function of the circulatory system, focusing on the heart, blood vessels, blood flow, and the importance of circulation in sustaining life.
Circulatory System Overview
- The circulatory system consists of the heart, blood vessels, and blood.
- Its main function is to deliver oxygen and nutrients to cells and remove cellular waste.
- The system is also known as the cardiovascular system.
Structure and Function of the Heart
- The heart has four chambers: left atrium, left ventricle, right atrium, and right ventricle.
- Left atrium receives oxygenated blood from the lungs and passes it to the left ventricle.
- Left ventricle pumps oxygen-rich blood to the aorta and out to the body.
- Right atrium receives deoxygenated blood from the body (systemic circulation).
- Right ventricle pumps deoxygenated blood to the pulmonary artery and lungs for oxygenation.
Major Heart Valves and Blood Flow
- The mitral valve prevents backflow from the left ventricle to left atrium.
- The aortic valve separates the left ventricle from the aorta.
- The tricuspid valve controls blood flow from the right atrium to the right ventricle.
- The pulmonary valve sits between the right ventricle and pulmonary artery.
- Proper valve function ensures one-way blood flow in the heart.
Major Blood Vessels
- The aorta is the largest artery and carries oxygenated blood from the heart to the body.
- The superior vena cava returns blood from the upper body to the right atrium.
- The inferior vena cava returns blood from the lower body to the right atrium.
- The pulmonary artery takes deoxygenated blood from the heart to the lungs.
Importance of the Circulatory System
- The system connects all cells, functioning like a transport network.
- It works with other body systems to provide materials and remove wastes.
- Blood circulation is vital for delivering oxygen, nutrients, and removing carbon dioxide and other wastes.
Key Terms & Definitions
- Oxygenated Blood — blood rich in oxygen, delivered from lungs to the body.
- Deoxygenated Blood — blood low in oxygen, returns from the body to the heart.
- Atrium (Atria) — upper heart chambers receiving blood.
- Ventricle — lower heart chambers pumping blood out.
- Artery — blood vessel carrying blood away from the heart.
- Vein — blood vessel carrying blood toward the heart.
- Capillary — tiny vessel where exchange of substances with cells occurs.
- Valve — structure that prevents the backward flow of blood.
- Leukemia — cancer of blood-forming tissues.
Action Items / Next Steps
- Review the path of blood through the heart and major vessels.
- Memorize the names and functions of the four heart valves.
- Study the differences between oxygenated and deoxygenated blood.