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23 Cards in this Set

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

↑ BP leads to ↑ CO leads to ↑ SV