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1. What are the three main types of blood vessels, and how do their structures differ?

The three main types of blood vessels are arteries, veins, and capillaries, and they differ in structure: arteries have thick, muscular walls to handle high pressure, veins have thinner walls with valves to prevent backflow, and capillaries are very thin with only one cell-layer of endothelium to allow exchange of materials.

2. Why do arteries have thicker walls than veins?

Arteries have thicker muscular walls than veins because they must withstand the high pressure of blood pumped from the heart, a key feature in hemodynamics.

3. How do capillaries facilitate the exchange of gases and nutrients?

Capillaries, made of thin endothelium, allow oxygen, carbon dioxide, nutrients, and wastes to easily pass between the blood and body tissues through diffusion in the vascular system.

4. What prevents blood from flowing backward in veins?

Veins contain valves that stop blood from flowing backward, especially in the limbs, helping maintain proper flow in the circulatory system.

5. How does blood pressure differ between arteries, veins, and capillaries?

Blood pressure is highest in arteries, lower in capillaries, and lowest in veins, due to changes in vessel diameter and distance from the heart in the vascular system.