Terms: 1/16, 16, arterioles and small arteries, denominator, flow, inverse, larg

Question

Terms: 1/16, 16, arterioles and small arteries, denominator, flow, inverse, large, length, numerator, parallel, radius, resistance, small, inverse, viscosity

kindly use these terms to fill the blanks..

___________ - symbolized by the letter 'R' represents the sum of the forces that oppose blood _________ through the vascular network. This 'R' force can be calculated from the following equation: R = x l/r4 x 8/ where represents the ___________ of the blood - that is, how thick or thin (i.e. how molasses-like or how thin and watery the blood is), l represents the __________ of the vessels that the blood must pass through, and r represents the __________ of the blood vessels through which the blood passes. The 8/ is simply a math 'constant' that must be included in the calculation for accuracy.Because the length and viscosity components are in the ____________ or upper part of the equation's fraction, changes in either or both of these factors causes _____________ changes in resistance. That is, if the length of the vessels that the blood passes through and/or the thickness of the blood increase, resistance also increases. In contrast, because the radius [of the vessel] factor is in the __________ - that is, is on the bottom of the equation fraction - changes in the radius of the vessel(s) that the blood passes through cause _____________ changes in resistance. This means that if the radius of the vessel(s) decrease, resistance increases and vice versa. Because the radius factor is raised to the 4th power, _________ changes in the radius of a vessel evoke very __________ changes in resistance.

Basically, the length of the vasculature is fairly constant in the human body, as is the viscosity of blood from minute to minute. Therefore, it is changes in the radius of the blood vessels that have the biggest impact on resistance to flow of blood through the vascular network. Take for example a vessel whose radius changes from 1 mm to 2 mm. At the vessel's initial radius of 1 mm, R = 1/14 (which = 1/1x1x1x1x1) x (l x 8/) which = 1 x (l x 8/). At the increased radius of radius = 2 mm, R = 1/24 (which = 1/2x2x2x2) = 1/16 x (l x 8/) - so resistance is _______ of what it was when the radius had just a slightly smaller radius. Because resistance is, essentially, the inverse of flow - this means that _______ times more blood flows through the vessel when its radius = 2 mm as compared to when it equaled 1 mm. ____________ are considered the 'resistance' vessels because they have the largest relative amount of smooth muscle of all the blood vessels. In response to autonomic nervous system input, these vessels are able to increase or decrease their diameters (and radii, since diameter = 2 x radius) to let blood into or make it by-pass specific capillary beds at any given time - in order to meet tissue oxygen needs on a minute to minute basis.

Explanation / Answer

1. Resistance

2. flow

3. viscosity

4. length

5. numerator

6. large

7. denominator

8. Inverse

9. small

10. Large

11. 1/16

12. 16

13. Arterioles and small arteries

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

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