Lec 22 Flashcards

1
Q

During ventricular ejection, blood presuure

A

will cause arteries to stretch and expand and store pressure in elastic walls

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2
Q

During isovolumc ventricular relaxation, how blood goes forward

A

the pressure that was stored in elastic walls, will recoil to maintain pressure

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3
Q

blood presuure measured in

A

arteries

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4
Q

pulse pressure

A

systolic pressure - diastolic pressure

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5
Q

mean arterial pressure formula

A

Diastolic pressure + 1/3 (pulse pressure)

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6
Q

why MAP formula is like that

A

as bloood spend less time in systolic than diastolic

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7
Q

MAP calculation in 120/80 BP

A

80 +1/3(120-80)=80+13.3=93.3

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8
Q

MAP illustrates

A

Mass balance

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9
Q

what do we mean by mass balance

A

what comes in, should go out

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10
Q

MAP minimum

A

60

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11
Q

two main ways bp is regulated

A

1- fluid loss/retention of kidneys
2- arterial tone -> vasodilation/vasoconstriction

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12
Q

four elements acting on MAP

A

1- Blood vloume
2- CArdiac output
3- resistance of system
4- relative distribution of blood (mass balance)

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13
Q

if MAP increase what have happened to four major elements

A

1- blood vol. increase (higher intake/lower loss)
2- cardiac output increases
3- resistance increase
4- diameter of veins decrease

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14
Q

cardiac output increase by (2 factors)

A

1- higher HR – dual input sym/parasym
2- Higher SV – contractility only by sympathetic

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15
Q

higher resistance is due to

A

lower diameter of arterioles

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16
Q

lower diameter of veins is leads to (4step in order)

A

1- higher venous constriction
2- higher venous return
3- higher sv
4- higher MAp

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17
Q

two systems acting in response of increase in BV/Bp

A

1- cardiovascular
2- renal system

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18
Q

response to high BV is —- feedback

A

negative

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19
Q

high BV triggers two different response

A

1- fast response (sec-min)
2- slow response (hour-days)

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20
Q

slow response to BP

A

compensation by kidneys (excretion of fluid in urine

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21
Q

fast response to high bp

A

compensation by cardiovascular system
1- vasodilation
2- lower CO

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22
Q

arteriole resistance formula

A

Ln/r^4 (n is viscosity)

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23
Q

in resistance formula — and — is not changing

A

length and viscosity

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24
Q

radius can be changed by changes in

A

vascular smooth muscle

25
changes in vascular muscle is due to
*local factors: 1- Myogenic response 2- paracrine *3-Sympathetic nervous system
26
Myogenic autoregulation
constriction blood flow in response to increase pressure
27
myogenic is
wall of muscle from within
28
myogenic autoregulation pathway
1-pressure high 2- stretch in arteriole 3- open mechanically gated channels on smooth muscles 4- cell depolarize 5- opens voltage gated Ca channels 6- CA in smooth muscle (4 output)
29
Ca in smooth muscle will lead to
1- high contraction 2- higher arteriolar resistance 3- lower blood flow 4- lower pressure through vessel
30
myogenic response will hepl an organ to
maintain a constant blood flow as changes in perfusion pressure
31
Paracrine release
1- Active hyperemia 2- reactive hypermia
32
Active hyperemia
matching flow to metabolic demand muscles working harder
33
active hypermia patheway
1- higher tissue metabolism 2- metabolites released from local cells act on arterile smooth muscle 3- smooth muscle decrease cross-bridge cycling 4- vasodilation 5- lower resistance 6- higher blood flow
34
some paracrine cause relaxation of muscle cells
O2/CO2/H+/NO/ADP
35
Reactive hypermia
1- lower blood flow due to blockage 2- build up metabolites (vasodilators in ECF) 3- arteriole dilate but flow still blocked 4- faster pace will wash blockage 5- short period of increased blood flow as low resistance 6- metabolites wash out 7- arterioles regain normal tone
36
SNS exert tonic control on
MOST arteriole resistance
37
SNS tonic control via
1- NPH 2- ephinephrine
38
Norepinephrine pathway
1- NPH release from postganglionic sympathetic neurons 2- bind alpha 1- adrenergic receptor on smooth muscles 3- alpha 1 coupled to Gq proteins (activate PLC) 4- increase in IP3 5- increase Ca release from SR-- IP3 6- smooth muscle cell contraction (vasoconstriction)
39
Contraction increases during --
exercise and stress
40
higher expression of alpha 1 adrenergic receptors in
skin and visceral organs (GI tract) to have more blood for muscles
41
Epinephrine pathway
1- release from adrenal medulla 2- during fight/flight- or exercise 3- act on betta 2 adrenergic receptors on smooth muscles, heart ,liver 4- Betta 2 coupled to Gs 5- cAMP activation 6- cause smooth muscle relaxation 7- contraction decrease during exercise
42
higher expression of betta 2 receptors on
vascular smooth muscle supplying heart, lungs, liver more blood supply during fight/flight
43
central control of MAP
Baroreceptor reflex
44
Baroreceptors are -- sensors
pressure
45
baroreceptors are located in
wall of carotid sinus and aortic arch
46
baroreceptors are
nerve endings with stretch-activated channels
47
baroreceptor reflex is ----
tonically active always active more or less
48
baroreceptor stimulus
high pressure
49
baroreceptor effect on
1- open more channels 2- more depolarization 3- higher AP frequency
50
baroreceptor reflex ensures
adequate blood flow to heart and brain
51
baroreceptor sensor
carotid and aortic baroreceptor
52
baroreceptor integrating center
medullary cardiovascular control center
53
baroreceptor integrating center will effect on
1- parasympathetic neurons 2- sympathetic neurons **always one active one inactive**
54
Parasympathetic neuron will
release more ACh on muscarinic receptor in SA node -lower HR --lower CO ---lower BP ----lower MAP
55
sympathetic neuron will
release less NE on 1- alpha receptor (arteriolar smooth muscle) 2- betta 1 receptors (ventricular myocardium and SA node)
56
alpha receptor (arteriolar smooth muscle) when less NE release
vasodilation -lower periheral resistance --lower BP ---lower MAP
57
betta 1 receptors (ventricular myocardium) when less NE release
lower force of contraction -lower SV --lower CO ---lower BP ----lower MAP
58
betta 1 receptors (SA node) when less NE release
lower HR -lower CO --lower BP ---lower MAP
59
lowering MAP will have ---- feedback directly on ----
negative on baroreceptors in arteries and aorta