Below are the solutions to the Hematocrit (Parts 1 and 2) Self-Assessment Questions:
- False.
Hematocrit is the percent volume of red blood cells in the blood, not the number of red blood cells. - B. 35-50%
This number is on the higher side (41-50%) for men and on the lower side (36-48%) for women. Age and sex also play a role on the exact hematocrit in this range. - C. Decrease 8x
As stated in the video, R = (8*viscosity*length)/(pi*r^4). Doubling the length would increase the resistance by a factor of 2, while doubling the diameter (which also doubles the radius) will decrease the radius by a factor of 16 since 2^4 = 16. Therefore, the overall effect is an 8x decrease in resistance since 2/16 = 1/8. - True
Refer to the second practice problem of the lesson. Polycythemia increases blood viscosity as stated in the question, and as the answer reflects, viscosity is directly proportional to resistance, thus causing flow resistance to increase as well.
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