Arteries vs. Veins: Structure, Function, and Key Differences

Circulatory System: Arteries and Veins

Arteries and veins are the two main types of blood vessels, differing in structure, function, and blood content.

Arteries

• Function: Carry oxygenated blood away from the heart to the body (except pulmonary artery).
• Structure: Thick, muscular, elastic walls to withstand high pressure.
• Location: Generally deeper in the body.
• Pressure: High (systolic/diastolic).
• Branching: Divide into arterioles, then capillaries.
• Disease susceptibility: Prone to atherosclerosis (plaque buildup).

Veins

• Function: Return deoxygenated blood to the heart (except pulmonary vein).
• Structure: Thinner walls, larger lumen; contain valves to prevent backflow.
• Location: Often superficial (visible under skin).
• Pressure: Low; rely on muscle pumps and valves.
• Capacity: Hold ~70% of blood volume (capacitance vessels).

Key Differences Summary

Feature	Arteries	Veins
Blood oxygen	High (oxygenated)	Low (deoxygenated)
Wall thickness	Thick, muscular	Thin, less muscular
Valves	Absent	Present
Pressure	High	Low
Pulse	Palpable	Not palpable
Color (gross)	Bright red	Dark red

Exceptions: Pulmonary artery carries deoxygenated blood to lungs; pulmonary vein carries oxygenated blood to heart.