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23 Cards in this Set
- Front
- Back
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What are the four main factors affecting blood pressure?
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1. peripheral resistance
2. vessel elasticity 3. blood volume 4. Cardiac output |
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Blood cells and plasma encounter resistance when they contact blood vessel walls. What is this resistance called?
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peripheral resistance
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Is more or less pressure needed to keep blood moving when resistance increases?
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more
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What are the three main sources of peripheral resistance?
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1. vessel diameter
2. blood viscosity 3. total vessel length |
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What is the relationship between the diameter of a tube and the proportion of fluid that is in contact with the wall of the tube?
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The smaller the diameter the more pressure
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What is the relationship between the diameter of a tube and resistance to flow? What effect does this have on pressure?
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The small the diameter the more resistance to flow. This will increase pressure.
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Does constriction of blood vessels raise or lower blood pressure?
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raise
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What actively regulates the diameter of blood vessels?
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vasomotor fibers
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.) What chemical is released by vasomotor fibers that acts as a powerful vasoconstrictor?
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NE
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List three blood-borne vasoconstrictors?
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E
Angiotensin II vasopressin |
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It related to the thickness of a fluid. This affects peripheral resistance.
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viscosity
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What is the relationship between viscosity and pressure required to pump a fluid?
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Viscosity is a great resistance to flow, and that leads to greater pressure that is required to pump the same volume of viscous fluid.
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The percentage of rbc's in the total BV. It increases as a result of either more rbc's or less plasma in the blood. It can decrease because of either fewer rbc's or more plasma.
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hematocrit
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What is the effect of hematocrit on blood viscosity?
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It effects the resistance to flow
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When does hematocrit increase?
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It increases when there are more rbc's or less plasma.
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What is the relationship between the total vessel length, resistance, and blood pressure?
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The longer the total vessel length, the greater the resistance encountered, and the greater the BP.
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Why is expansion and recoil of the elastic arteries important?
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Expansion absorbs shock of systole pressure & recoil serve to maintain the cont flow during diastole.
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Why does blood pressure often increase in individuals with arteriosclerosis?
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Arteries become calcified & rigid & can't expand
Artery walls experience higher blood pressure. |
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What is the relationship between blood volume and blood pressure?
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The more BV, more fluid pressing against the walls, the greater the pressure.
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What is the relationship between blood pressure and cardiac output?
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Decreased HR leads to decreased CO which leads to decreased BP and visa versa.
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What is the relationship between heart rate, stroke volume and cardiac output?
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CO = HR X SV
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What happens to heart rate, cardiac output, and blood pressure with both parasympathetic and sympathetic stimulation?
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PNS decreases all
SNS increases all |
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What is the relationship between venous return and stroke volume?
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↓ SV leads to ↓ CO leads to ↓ BP
↑ BP leads to ↑ CO leads to ↑ SV |
