Question 11 When measuring blood pressure, a pump is used to inflate a band that

Question

Question 11 When measuring blood pressure, a pump is used to inflate a band that squeezes the upper arm, causing the brachial artery to temporarily collapse. The pressure in the band is measured using a manometer. When pressure in the band is reduced, the artery begins to open up and makes special sounds called Korotkoff sounds. When the pressure is reduced even more, these sounds end and normal blood flow resumes in the artery. A schematic of a mercury-filled manometer is shown below, with measurements a doctor could have been recording to determine the blood pressure (in mm of mercury). Mercury has a density Pm-13.59 g/cm3. atm blood h, 120mm h2-80mm mercu (a) What is Pascal's principle and how does it apply to measuring blood pressure? (b) What causes the artery to re-open as the pressure in the manometer is reduced? (c) How do h? and h2 relate to the problem statement? Use the schematic to determine the (1 mark) (1 mark) (3 marks) pressure (in SI units) when the Korotkoff sounds started and stopped.

Explanation / Answer

(a) Pascal Principle -Pascal's law is a principle in fluid mechanics that tell that a pressure change occurring anywhere in a confined incompressible continuous fluid is transmitted throughout the fluid such that the same change occurs everywhere.We can use it to find change in pressure in blood as blood can be considered incompressible fluid .

(b)As Pressure in manometer is reduced ,it means blood pressure is reduced forcing artery to open as blood inside artery will be al low pressure

(c)We knoW

Pressure difference =density*g*change in height

change in height=2*(h1-h2)

so pressure difference is

=9.8*13590*2*(h1-h2)=10654.56 pa

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.