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Question
Why can you feel a pulse when you keep a finger on the wrist or neck but not when you keep them on a vein?
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Solution
- Pulse is the series of pressure waves that travel through arteries due to ventricular systole.
- When the heart contracts, it produces pressure that pulls blood out of the heart. This pressure operates as a wave, which corresponds to the pulse you feel. However, this pressure is not consistent.
- When the heart pumps blood out of itself during systole, the arteries are at their maximum pressure. This pressure decreases significantly when it reaches capillaries; therefore, the veins farthest from the heart are under less pressure. Due to the low pressure, veins include valves to prevent blood backflow.
- The pressure in the arteries can be felt whenever the heart beats, particularly in arteries that come to the surface of the body, such as those in the wrist and neck, but not in veins.
- Vein pressure is usually lower than arterial pressure, resulting in a weaker pulse that cannot be detected by touch alone.
- As a result, we may feel a pulse when we place our fingers on the arteries of the wrist or neck but not when we place them on a vein.
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