Final answer:
The physiological mechanism of the cold pressor test involves immersing the hand in ice water, activating the sympathetic nervous system and causing vasoconstriction and increased heart rate and blood pressure. In normotensive individuals, the systolic pressure may rise only 10 mm Hg due to efficient blood vessel constriction.
Step-by-step explanation:
The physiological mechanism of the cold pressor test involves immersing a person's hand in ice water for a specific duration, typically 1 to 3 minutes. This activates the body's sympathetic nervous system, causing vasoconstriction and increased heart rate and blood pressure. In a normotensive individual, the systolic pressure may rise only 10 mm Hg because their blood vessels are able to constrict efficiently, maintaining blood pressure within a normal range.