When the heart pumps blood into the aorta, the pressuregradient-the difference between the blood pressure inside the heartand the blood pressure in the artery-is an important diagnosticmeasurement. A direct measurement of the pressure gradient isdifficult, but an indirect determination can be made by measuringthe Doppler shift of reflected ultrasound. Blood is essentially atrest in the heart; when it leaves and enters the aorta, it speedsup significantly and-according to Bernoulli's equation-the pressuremust decrease. A doctor using ultrasound of 2.5 MHz measures a 5400Hz frequency shift as the ultrasound reflects from blood ejectedfrom the heart.
Part A
What is the speed of the blood in the aorta? Assume that the speedof sound in human body is 1540 m/s
A:1.7 m/s
***Part B
What is the difference in blood pressure between the inside of theheart and the aorta? Assume that the patient is lying down and thatthere is no difference in height as the blood moves from the heartinto the aorta.
When the heart pumps blood into the aorta, the pressuregradient-the difference between the blood pressure inside the heartand the blood pressure in the artery-is an important diagnosticmeasurement. A direct measurement of the pressure gradient isdifficult, but an indirect determination can be made by measuringthe Doppler shift of reflected ultrasound. Blood is essentially atrest in the heart; when it leaves and enters the aorta, it speedsup significantly and-according to Bernoulli's equation-the pressuremust decrease. A doctor using ultrasound of 2.5 MHz measures a 5400Hz frequency shift as the ultrasound reflects from blood ejectedfrom the heart.
Part A
What is the speed of the blood in the aorta? Assume that the speedof sound in human body is 1540 m/s
A:1.7 m/s
***Part B
What is the difference in blood pressure between the inside of theheart and the aorta? Assume that the patient is lying down and thatthere is no difference in height as the blood moves from the heartinto the aorta.
