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259 - physiology > lecture 5: chapter 14/15 > Flashcards

lecture 5: chapter 14/15 Flashcards

(72 cards)

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1
Q

where is blood pressure on the circulatory system the highest

A

in the aorta and largerer arteries

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2
Q

true or false: the pressure stays constant at the aorta

A

true (relatively constant)

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3
Q

Why does the pressure drop significantly at the arteriole/capillary junction

A

They are area of high resistances

Allows velocity to slow for exchange

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4
Q

true or false: the pressure in the systemic circulation stays constant throughout the entire passage

A

false, it decreases until it is at the lowest velocity and pressure near the capillaries

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5
Q

when the blood returns in the right atrium the pressure is 0 mmHH

A

true

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6
Q

where are there lower pressure: arteriol or venous side?

A

venous side

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7
Q

what is peripheral resistance

A

the friction between the blood and vessel wall

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8
Q

what is the main determinant of resistance

A

radius

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9
Q

where is flow faster: larger or smaller vessels

A

faster in large

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10
Q

explain why a smaller radius means a higher resistance

A

because there an increased surface area exposed to blood which will increase resistance (look at slide 3 from 14/15)

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11
Q

what is the relationship between resistance and radius

A

if you increase radius, flow is 16x greater (flow=r4)

Resistance decreases 4 fold (resistance=1/r4)

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12
Q

what are some examples of things that increase resistance

A

abrupt changes in diameter, fatty plaques from atherosclerosis, branching, or sharp turns

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13
Q

what do abrupt changes in direction, fatty plaques etc do in terms of resistance

A

increase resistance and disrupt laminar flow and cause turbulence flow

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14
Q

what is turbulent flow

A

irregular fluid motion that increases resistance

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15
Q

explain why people with heart plaque have hypertension

A

because plaque causes build up in arteries with increases resistance and ie need more pressure to overcome

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16
Q

explain laminar flow

A

during laminar flow all the vectors flow in parallel with the highest velocity and and least friction in the center of the vessels

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17
Q

what are the 3 main determinants of resistance

A

blood viscosity
vessel length
vessel radius

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18
Q

blood is more viscous in what season and gender

A

in men and summer

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19
Q

what is poiseuille’s law

A

flow= (pie)(delta pressure)(radius)^/8nl

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20
Q

what does conductance mean

A

how easy is is to move blood from point a to b

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21
Q

what is the formula for conductance

A

1/resistance

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22
Q

what is the problem with circualtion in series

A

the flow is affected by all resistances

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23
Q

where is an area in the body where blood flows in series

A

in the pulmonary circulation (from heart, to lungs and back to heart)

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24
Q

what is imporant about circulation in parallel

A

it is important for how the body regulates where the blood is going in the body
it allows for separate resistance paths

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25
what is the difference between Q and F
Q is the flow through the entire circulation | F is the flow through a certain segmaent
26
what is the formula for flow
q=pressure/resistance
27
what is the flow through a blood vessel determined by
1) the pressure difference between the two ends of the vessel 2) the resistance of the vessel
28
if pressure increases (and resistance is constant) what happens to the flow
it increases
29
if resistance increases (and pressure is constant) what happens to the flow
flow decreases
30
the diastolic pressure is taken at the end of
the resting phase when the aortic valve opens
31
after ventricular ejection and pressure is decreases, why does it start to increase again
incisura increase in pressure due to the bouncing off of the peripheral resistance = important for filling coronary arteries
32
when the left ventricle contracts... more or less blood enters into arterial system
more blood enters the arterial system than gets pushed onwards
33
what does the fact that more blood enters the arterial system than gets pushed out when the left ventricle contracts cause what
causes arteries to stretch and pressure within them rises
34
the highest pressure in the aorta is called..
systolic
35
what happens when the left ventricle relaxes (in terms of recoil)
the stretched arterial walls recoil and push the contained blood onward through the system
36
what pushes blood onwards into the circulatory system
the elastic recoil of the arteries (compliance)
37
as the arteries recoil what happens to the blood and pressure
the amount of blood contained decreases and as does pressure
38
the lowest pressure achieved just before the next contraction is called...
diastolic pressure
39
what does arterial compliance mean
the ability to expand and recoil | "a change in pressure will affect a change of volume)
40
what is the formula for arterial compliance?
compliance=change in volume/change in pressure
41
the walls of which vessel are stronger
arteries stronger than veins
42
which vessel has a thicker outer layer but less muscle
veins
43
which vessel has thicker walls and how
arteries are more rigid because they have more smooth muscle
44
the arteries are less or more distensible than the veins
less
45
the arteries are blank times less distensible than the veins
8 times less
46
an increase in pressure causes 8 times as much increase in blood in a blank
in a vein as in an artery of comparible size
47
if a vein and artery are both subjected to 100 mmHG, how much volume will be in the artery vs vein
artery: 100 ml | vein 800 ml
48
what is the reason the veins can hold more blood given the same pressure increase as a artery
because of their looser wall (with less smooth muscle), they are more distensible and compliant allowing more blood
49
which vessels are known as the capacitance vessels and why
veins since they are the ones that hold the blood
50
what does vascular distensibility mean
is the fractional increase in volume for each mmHG rise in pressure
51
veins are more or less distensible than arteries
8 times more distensible
52
which arteries are known to be relatively distensible
pulmonary
53
what is the formula for vascular distensibility
VD= increase in volume/(increase in pressure)(original volume)
54
true or false : vascular distensibility isnt imporant for circualtory function
false,it plays an important role
55
what does the distensible nature of the arteries allow
allows them to accommodate the pulsatile output of the heart and to average out the pressure pulsations =provides smooth continuous flow of blood through the very small blood vessels and tissues
56
explain how vascular distensibility allows pulsatile to go to continuous
every time a larger vessel expands and recoil it can flatten and dampen the pulsatile flow -=some of the energy stored in the wall as kinetic becomes potential and the pressure goes forward instead of laterally
57
what is vascular capacitance
the total capacitance of blood that can be stored in a given portion of the circulation for each mmHG
58
what is the formula for capacitance
distensibility x volume
59
even slight increases in venous pressures cause what
cause veins to store 0.5-1 litre of extra blood
60
if there is a slight increase in pressure what does that mean veins can provide
provide a reservoir function for storing large quantities of extra blood that can be called into use whenever required elsewhere in circulation
61
true or false: the arteries serve as a reservoir for storing blood
false, the veins
62
the capacitance of the veins is smaller or higher than the arteries
the capacitance of veins is 24 times that of the arteries
63
any given change in volume within the arterial tree results in...
larger increase in pressure than in veins
64
what happens to the blood when veins do vasoconstriction
large quantities of blood are transferred to the heart, thereby increasing cardiac output due to an increase in venous return (because of compliance) =more blood comes in
65
what is the formula for pulse pressure
Sys. BP-diastolic BP
66
what are the 2 advantages of distensibility and compliance
1) saving energy for the heart | 2) pulsatile flow to continuous
67
in the pressure curve, why do we get an elongated tail and why is that beneficial
elongated tail because of the compliance (the recoil propel the blood forward so it saves work for the heart)
68
what is the "ohms law" for circulation
q=delta p/r
69
CO is the ...
flow
70
what are the two sources of the pressure
mean arterial pressure and central venous pressure
71
what is the source of resistance in the body
systemic vascular resistance
72
KNOW THE LAST TWO SLIDES

259 - physiology (21 decks)

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