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I have the 2013 Berkeley Review Biology on page #124, I have a question: Why is it Systolic Pressure - Diastolic Pressure as opposed to the other way around? Below is the actual question and what I did...
54. The pulse pressure is the difference between the diastolic pressure and the systolic pressure. It can be used to calculate the mean arterial pressure (MAP) during the cardiac cycle.
MAP = diastolic pressure + (pulse pressure/3)
What is the MAP, on average, for a 27-year-old man?
A. 51 B. 62 C. 78 D. 94
What I did:
MAP = Diastolic Pressure + (pulse pressure/3)
MAP = Diastolic Pressure + ([Diastolic Pressure - Systolic Pressure]/3)
From the passage for 25 - 29 years old men Diastolic Pressure is 78 mm/Hg, while the Systolic Pressure is 125 mm/Hg.
Therefore:
MAP = 78 + [(78 - 125)/3]
MAP = 78 + [- 47/3]
I round down 47 to 45 for easier calculation.
MAP = 78 + [- 45/3]
MAP = 78 - 15 = 63.
This would be choice B.
Correct answer given:
A 27-year-old man, on average, would have a systolic pressure of 125 and a diastolic pressure of 78. The difference between the two reading is 125 - 78 = 47. The pulse pressure is 47. MAP = 78 + (47/3) = 78 + 16 = 94. The correct choice is D.
My Question Please:
Why was it Systolic Pressure - Diastolic Pressure, as opposed to Diastolic Pressure - Systolic Pressure?
Thanks in advance.
54. The pulse pressure is the difference between the diastolic pressure and the systolic pressure. It can be used to calculate the mean arterial pressure (MAP) during the cardiac cycle.
MAP = diastolic pressure + (pulse pressure/3)
What is the MAP, on average, for a 27-year-old man?
A. 51 B. 62 C. 78 D. 94
What I did:
MAP = Diastolic Pressure + (pulse pressure/3)
MAP = Diastolic Pressure + ([Diastolic Pressure - Systolic Pressure]/3)
From the passage for 25 - 29 years old men Diastolic Pressure is 78 mm/Hg, while the Systolic Pressure is 125 mm/Hg.
Therefore:
MAP = 78 + [(78 - 125)/3]
MAP = 78 + [- 47/3]
I round down 47 to 45 for easier calculation.
MAP = 78 + [- 45/3]
MAP = 78 - 15 = 63.
This would be choice B.
Correct answer given:
A 27-year-old man, on average, would have a systolic pressure of 125 and a diastolic pressure of 78. The difference between the two reading is 125 - 78 = 47. The pulse pressure is 47. MAP = 78 + (47/3) = 78 + 16 = 94. The correct choice is D.
My Question Please:
Why was it Systolic Pressure - Diastolic Pressure, as opposed to Diastolic Pressure - Systolic Pressure?
Thanks in advance.
