7.1 The Circulatory System
- Double Circulation: Humans have a double circulatory system.
- Pulmonary Circulation: Blood from the heart to the lungs and back.
- Systemic Circulation: Blood from the heart to the body and back.
7.2 Structure of the Heart
| Part | Function |
|---|
| Right Atrium | Receives deoxygenated blood from the body. |
| Right Ventricle | Pumps deoxygenated blood to the lungs. |
| Left Atrium | Receives oxygenated blood from the lungs. |
| Left Ventricle | Pumps oxygenated blood to the body. |
| Valves | Prevent backflow of blood. |
| Aorta | Carries oxygenated blood to the body. |
| Vena Cava | Brings deoxygenated blood from the body to the heart. |
| Pulmonary Artery | Carries blood from the heart to the lungs. |
| Pulmonary Vein | Carries blood from the lungs to the heart. |
7.3 Blood Vessels
| Vessel | Structure | Function |
|---|
| Arteries | Thick walls, narrow lumen | Carry blood away from the heart. |
| Veins | Thin walls, large lumen, valves | Carry blood to the heart. |
| Capillaries | Thin walls (one cell thick) | Exchange of gases, nutrients, and waste. |
7.4 Blood and its Components
| Component | Function |
|---|
| Red Blood Cells | Carry oxygen using hemoglobin. |
| White Blood Cells | Fight infection. |
| Platelets | Help blood clot. |
| Plasma | Transports nutrients, gases, hormones. |