acute cardiovascular response to exercise Flashcards
(106 cards)
1
Q
three factors regulating venous return during exercise
A
- constriction of the veins (venoconstriction)
-pumping action of contracting skeletal muscle (muscle pump) - pumping action for the respiratory system (respiratory pump)
2
Q
what is Cardiac output (Q)
A
- the amount of blood pumped by the heart each minute
3
Q
at rest CO should be at?
during exercise?
A
- 5L per/min at rest
- 20-35 L/min during exercising
4
Q
Components of CO
A
- product of HR and SV
5
Q
stroke volume is the volume of
A
blood ejected with each heartbeat
6
Q
another variable that affects SV is
A
aortic pressure (MAP)
7
Q
if you have an increase of mean arterial pressure, what happens to stroke volume?
A
decrease
8
Q
final factor that influxes stroke volume is the effect of circulating
A
- catecholamine (N/NE)
- direct sympathetic stimulation of the heart by cardiac accelerator nerves
9
Q
overall, what three factors affect CO
A
- EDV
- Cardiac contractility
- cardiac after load (aortic blood pressure)
10
Q
increase of CA influx into the myocardial cell would cause?
A
cardiac contractility
11
Q
increase in cardiac afterload results in a
A
decrease in stroke volume
12
Q
Factos affecting cardiac rate
A
- parasympathetic
- sympathetic nerves
13
Q
factors affecting stroke volume
A
- sympathetic nerves
- frank starling
- EDV
- MAP
14
Q
blood flow is
A
the change of pressure over resistance
15
Q
what happens to blood flow when vascular resistance increase
A
blood flow decrease
16
Q
blood flow can be increased by
A
- increase in blood pressure
- decrease in resistance
17
Q
regulation of HR - PSNS
A
- via vagus nerve
- slows HR
- decreases contractility of the myocardium indirectly by inhibiting SNS
18
Q
regulation of HR - SNS
A
- via cardiac accelerator nerves
- increases HR by stimulation SA and AV node
- increases contractility of the myocardium directly
19
Q
Cardiovascular control center is in the
A
medulla oblongata
20
Q
medulla oblongata consists of 4 areas
A
- pressor area (vasoconstrictor)
- depressor area (vasodilator)
- cardiac acceleration
- cardiac inhibitory center
21
Q
increased oxygen delivery to exercising skeletal muscle is accomplished via two mechanism
A
- increase in CO
- redistribution of blood flow form inactive organs to the working skeletal muscle
22
Q
Fick Equation
A
VO2 = Q x (a-VO2diff)
23
Q
during exercise, blood flow to contracting muscle is increased, and blood flow to less active tissues is
A
reduced
24
Q
auto regulation refers to
A
intrinsic control of blood flow by increases in local metabolites
25
these factors work together to promote vasodilation to increase blood flow to the working muscles?
NO, prostaglandins, ATP, adenosine, and endothelium derived
26
what does NTS stand for
nucleus tractus solitarius - receiving inputs from afferent
27
vagal stimulation only goes
to the heart
28
sympathetic stimulation goes to the
heart and the blood vessels
29
glossopharyngeal nerve
carotid sinus
30
vagus nerve
aortic baroreceptors
31
a decrease in action potential frequency from the barorecepotros, should elicit
an increase in SNS activity
32
SNS response to decrease in bp effects on SA node
increase heart rate
33
SNS response to decrease in bp effects on myocardium
heart rate contractile
34
SNS response to decrease in bp effects on arteries
vasoconstrict
35
SNS response to decrease in bp effects on veins
stiffen
36
chemoreceptor reflex
- sensitive to decrease O2, increase CO2, increase hydrogen ion
- signals excite the vasomotor center
37
volume reflex
- atrial stretch = dilation of afferent arterioles in the kidney
- signals hypothalamus to decrease ADH
- atria release atrial natriuretic peptide (ANP)
38
abdominal compression reflex
baroreceptor and chemoreceptor reflexes also excite motor nerves to the abdomen
39
respiratory
- inspiration: decrease in BP
- early expiation: increase in BP
40
bainbridge reflex
- increase atrial stretch = increase HR and strength of contraction
41
increase in HR at onset of exercise
- initial increase due to parasympathetic withdrawal
- later increase due to increased SNS firing (outflow)
42
intrinsic rate of the heart is
90 to 100 bpm
43
Beta adrenergic blocking drugs (beta blockers)
- competes with E/NE for beta adrenergic receptors in the heart
44
function of beta blockers
reduce heart rate and contractility thus lowering the work of the heart and lowering myocardial oxygen demand
45
beta is prescribed for patients with
coronary artery disease, hypertension, and post heart attack
46
patients on beta blockers will have a lower cardiac output during
rest and exercise
47
the balance between SNS and PNS is known as
sypathovgal balance
48
the time between heart beats is determine by what interval
R to R interval
49
A wide variation in HRV is considered
healthy
50
Low HRV is a predictor of
cardiovascular morbidity and mortality
51
what is End diastolic volume
- volume of blood in the ventricles at the end of diastole
- preload
- depends on filling time and filling pressure
52
filling time depends on
HR
53
filling pressure depends on
central venous pressure
54
average aortic blood pressure
pressure the heart must pump against to eject blood
- afterload
- MAP
55
strength of the ventricular contraction (contractility) is enhanced by
- circulating E/NE
- direct sympathetic stimulation of the heart
56
SV =
EDV - ESV
57
frank starling mechanism is
greater EDV results in a more forceful contraction due to stretch of ventricles (length tension)
58
EDV depends on
venous return (ventral venous pressure) and filling time
59
venoconstriction is stimulated by
SNS
60
what is skeletal muscle pump
- rhythmical muscle contractions push blood toward the heart
- veins have one way valves
61
what is respiratory pump
changes in intrathoracic pressure pull blood toward the heart
62
venoconstriction
- veins collapse when there is no blood in them
- can store a lot of blood
- have only a thin layer of smooth muscles (tunica media)
63
vein stiffen when stimulated by
SNS (no true constriction)
64
how does veins collapse
no blood in them
65
Venous return is
the venous pressure and RA pressure over venous resistance
66
a decrease in RA pressure leads to
an increase in venous return and vice versa
67
how does venous return work ? 1-6
- inspiration
- descent of the diaphragm
- decrees in intrathoracic pressure
- decrease in right atrial pressure
- increase in abdominal pressure
- blood in inferior vena cava squeezed from abdomen into the right atrium
68
filling time can be describe as
- it relates to time in diastole (amount of time to fill)
- relaxation time (the fast the heat can relax, the more time it has to fill)
69
true or false: a short relaxation time is more important during exercise than at rest
true - so it can fill
70
increase EDV = increase of stroke =
increase of contractility
71
the higher the after load,
it will decrease stroke volume
72
increase of ESV results in
decrease of SV
73
increase in TPR results an
increase in after load
74
influence of mean aortic pressure (after load)
- the higher the after load, the harder the heart must contract to eject a given volume of blood
75
a high afterload will cause an increase or decrease of ESV
increase
76
a increased of total peripheral resistance will increase or decrease after load
increase
77
myocardial centrality is a direct stimulation of
cardiac accelerator nerves to the heart and SNS to adrenal medulla
78
once stimulated by cardiac accelerator nerves, what does E/NE do?
increase of extracellular calcium entry to myocardial cell
79
increase of extracellular Calum entry into the myocardial cell results an increased of
intracellular calcium
80
increase of intracellular calcium results an
increased of x bridge formation causing myocardial contractility
81
The study of the interrelationships between pressure, resistance, and flow and the physical principles of blood flow is called
hemodynamics
82
blood flow depends on
a pressure difference
83
blood flows from a region of
high pressure to region of low pressure
84
resistance is
length x (viscosity/Radius to the 4th power)
85
length typically
doesn't change
86
viscosity changes due to
dehydration
87
radius has a
large impact on resistance (vasoconstriction/vasodilation)
88
the perfect of blood that is composed of cells is called the
hematocrit
89
3 cell types of the blood sample
white blood cells, platelets, red blood cells and plasma
90
blood is several time more
viscous than water
91
major contirubot to vhsiscosit is the
RBC number
92
normal metocrit for male and female
- 42-48
- 38-42
93
increase in either vessel length or blood viscosity results an
increase in resistance
94
increase of resistance results
decrease in blood flow
95
MAP decreases through the
systemic ciruclaiton
96
largest BP drops occurs across the
arterioles
97
arterioles are called
resistance vessels
98
what regulate blood flows
arterioles
99
purpose of capacitance vessels
storage of blood
100
CO = HR x
SV
101
CO = ___ x EDV-ESV
HR
102
EDV depends on
preload
103
preload depends on
filling time and filling pressure
104
filling time depends on
HR
105
filling pressure depends on
venous return
106
ESV depends on
heart contractility and after load
