What is the difference between Arteries and Veins with blood pressure, valves, and flow direction?

Direct Answer

In the human circulatory system, arteries carry oxygenated blood under high pressure away from the heart to systemic tissues, while veins carry deoxygenated blood under low pressure towards the heart from body tissues.

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Comprehensive Comparison Table

| Anatomical Feature | Arteries | Veins |

| :--- | :--- | :--- |

| Direction of Flow | Away from heart $\rightarrow$ to body organs | From body organs $\rightarrow$ back to heart |

| Type of Blood | Oxygenated blood (bright red) | Deoxygenated blood (dark red/purplish) |

| Major Exception | Pulmonary Artery carries *deoxygenated* blood to lungs | Pulmonary Vein carries *oxygenated* blood to left atrium |

| Internal Valves | Absent (high continuous pressure prevents backflow) | Present (semilunar pocket valves prevent backflow against gravity) |

| Vessel Wall | Thick, highly muscular, and elastic | Thin, less muscular, with minimal elastic tissue |

| Lumen Size | Narrow lumen | Wide / Large lumen |

| Internal Pressure | High pressure with pulsatile flow ($120/80\text{ mmHg}$) | Low pressure with steady non-pulsatile flow ($5-10\text{ mmHg}$) |

| Anatomical Depth | Located deep within muscles (protects from injury) | Located superficially under the skin (visible as blue-green lines) |

| Condition After Death| Empty of blood | Full of stagnant clotted blood |