Structure & Function of Blood Vessels | Biology for GCSE/IGCSE - Year 11 PDF Download

How Structure of Blood Vessels is Adapted to their Function: Extended

Arteries

• Arteries possess thick muscular walls embedded with elastic fibers, enabling them to endure the substantial pressure exerted by blood flow and sustain blood pressure by recoiling after blood passage.
• They feature a relatively narrow lumen to uphold elevated pressure levels within the vessel.

Veins

• Veins are characterized by a spacious lumen, a design suited to accommodate the lower pressure of blood flow within them.
• They incorporate valves, crucial for impeding the reverse flow of blood, especially given the reduced pressure within veins.

Capillaries

• Possess walls that are exceptionally thin, typically just a single cell layer thick, facilitating the efficient diffusion of substances across them.
• Feature permeable walls, allowing for the controlled leakage of blood plasma, thereby enabling the formation of tissue fluid surrounding cells.

Arterioles and venules

• Arteries progressively narrow as they branch out from the heart, with the smaller vessels connecting arteries to capillaries known as arterioles.
• Similarly, veins undergo narrowing as they extend away from the heart.
• The slender conduits linking capillaries to veins are termed venules.