Overview
The lecture explains the location and protective structure of the heart, the heart’s main functions in blood circulation, and introduces key blood vessels and concepts in cardiovascular anatomy.
Heart Location & Protection
- The heart sits between the right and left lungs in the chest.
- The ribs protect the heart and lungs by forming a cage around them.
- Below the heart and lungs is the diaphragm muscle, which forms the floor of the chest cavity.
- The area containing the heart and lungs, enclosed by the ribs and diaphragm, is called the thorax.
- Left and right sides are from the perspective of the person whose heart it is.
The Need for Circulation
- Every cell in the body needs oxygen and nutrients from nearby blood vessels, and must remove waste (like carbon dioxide).
- Without blood flow, waste accumulates around cells, and they lack needed oxygen and nutrients, leading to cell death.
- Continuous blood flow keeps cells healthy by delivering supplies and removing waste.
Main Functions of the Heart
- The heart acts as a pump to create blood flow for all the body’s cells.
- Systemic flow refers to blood movement throughout the entire body, serving all cells.
- Blood enters the heart through two large veins: the superior vena cava (top) and inferior vena cava (bottom).
- The heart pumps blood out through the aorta, the body's main artery.
- Pulmonary flow is blood movement from the heart to the lungs and back, allowing oxygen to enter blood and carbon dioxide to leave.
Coronary Circulation
- The heart’s own muscle cells need oxygen and nutrients, supplied by coronary blood vessels (arteries and veins).
- Coronary vessels serve the heart muscle itself and are part of systemic flow.
Key Terms & Definitions
- Thorax — the chest cavity containing lungs and heart, enclosed by ribs and diaphragm.
- Diaphragm — the muscle forming the floor of the chest cavity, essential for breathing.
- Systemic flow — blood circulation to and from the entire body (except the lungs).
- Pulmonary flow — blood circulation between the heart and lungs.
- Superior vena cava — large vein bringing blood from the upper body to the heart.
- Inferior vena cava — large vein bringing blood from the lower body to the heart.
- Aorta — main artery carrying blood from the heart to the body.
- Coronary vessels — arteries and veins supplying the heart muscle itself.
Action Items / Next Steps
- Review the structure and function of the heart, thorax, and major blood vessels.
- Draw and label a diagram of the heart, lungs, ribs, and diaphragm for study.