lecture 11: cardiovasc reg., functional capacity etc Flashcards
(121 cards)
1
Q
beta cells do dilation or constriction
A
dilation
2
Q
alpha receptors do constriction or dilation
A
constriction
3
Q
true or false;Any increase in energy expenditure requires rapid adjustments in blood flow
A
true
4
Q
how does increase in energy expenditure (rapid adjustments in blood flow) impact the entire cardiovascular system
A
takes blood from unimportant tissues (not needed for activity atm) and redistributes it to the needed muscle
5
Q
During exercise, local arterioles of active muscles dilate or constrict
A
dilate
6
Q
During exercise, vessels to tissues that can temporarily compromise their blood supply, constrict or dilate
A
constrict
7
Q
during exercise what happens to the vessels of the active and resting vessels
A
active muscle vessels dilate while inactive constriction
8
Q
give an example of inactive muscle constricting to redistribute blood flow
A
ex: during running, your gut and kidney vessels will constrict and your skeletal will dilate
9
Q
what are the 2 factors that contribute to reduced blood flow to non-active tissues:
A
Increased sympathetic nervous system outflow
Local chemicals that directly stimulate vasoconstriction or enhance the effects of other vasoconstrictors
10
Q
true or false: Increased sympathetic nervous system outflow contributes to increased blood flow to non-active tissues
A
false, DECREASE BLOOD FLOW
11
Q
epinephrin released by sympatethic will active what types of receptors
A
beta and alpha
12
Q
skeletal muscle blood flow couples to what
A
metabolic demand (will not waste sending oxygen if not needed)
13
Q
how does regulation of active myscle flow occur
A
Regulation occurs from the interaction of neural vasoconstriction activity and locally derived vasoactive substances within the endothelium and red blood cells
14
Q
at rest, what is happening at the capilary of sksletal muscle
A
only 1 in 30-40 capilarries remains open
because increase blood supply is not needed at rest
15
Q
what are the 3 functions of the opening of dormant capilaries in exercises
A
Increase total muscle blood flow
Deliver a large blood volume with only a minimal increase in blood flow velocity
Increase the effective surface for gas and nutrient exchange between the blood and muscle fibers
16
Q
true or false: you must increase blood velocity to increase the amounft of blood volume to tisse
A
false, you can just open dormant capilaries
17
Q
vasodilation occurs from local factored related to what
A
related to tissue metabolism that act directly on the smooth muscle bands of small arterioles and precapillary sphincters
18
Q
what are some local factors that act directly on vasodilation
A
Decreased tissue oxygen, local increases in blood flow, temperature, carbon dioxide, acidity, adenosine, magnesium and potassium ions, and nitric oxide production by the endothelial cells lining the blood vessels
19
Q
can the venous side release vasodilatory factors>
A
yes if there needes to be active msucle
20
Q
what is the function of nitric oxide
A
serves as an important signal molecule that dilates blood vessels and decreases vascular resistance
21
Q
is NO a constrictor or dialtor
A
Dialator
22
Q
what are exmaples of things that provoke NO synthesis and release
A
Stimuli from diverse signal chemicals, sheer stress and vessel stretch from increased blood flow through the vessel lumen
23
Q
how is NO released
A
vascular endothelium
24
Q
where are places that the endothelium produces less NO
A
In coronary artery disease (atherosclerosis), diabetes and other disruptions of normal cardiovascular function
(less. vasodilation)
25
what is cardiac output expresses
the amount of blood pumped by the heart during a 1-minute period
26
what deos CO reflect
functional capacity of the cardiovascular system
27
what is the formualte for cardiac output
Cardiac output = Heart rate x Stroke volume
28
what are 3 methods to assess cardiac output
Direct Fick
Indicator dilution
CO2 rebreathing
29
what does direct fick method express
Expresses the relationships among cardiac output, oxygen consumption, and a-vO2 difference
30
true or false: direct fick is complex?
true
| Requires complex methodology usually performed in a hospital
31
how can you get CO from direct fick method
Measuring oxygen consumption involves open-circuit spirometry methods
Measuring a-vO2 difference involves a sample of arterial blood and from an anatomic “mixing chamber”, then sampling arterial and mixed-venous blood simultaneously
32
explain the indicator diluation method
A known quantity of an inert dye whose concentration curve can be measured in blood by light absorption is injected into a large vein
The indicator material remains in the vascular stream and then mixes in the blood as the blood travels to the lungs and returns to the heart before ejection throughout the systemic circuit
A photosensitive device continually assesses arterial blood samples and the area under the dilution–concentration curve reflects the average concentration of indicator material in blood leaving the heart
33
what two methods use open circuit spirometry
co2 rebreathing method
| direct fick
34
explai nthe co2 rebreathing method
The same open-circuit spirometry method for determining O2 consumption in the typical Fick technique determines CO2 production in the rebreathing method
Using a rapid CO2 gas analyzer and making reasonable assumptions about gas exchange provides valid estimates of mixed-venous and arterial CO2 levels
Requires breath-by-breath CO2 analysis
Does not require blood sampling or medical supervision
One limitation is that exercise must be under steady-rate aerobic metabolism, restricting the method’s use during maximal and in the transition from rest to exercise
35
true or false: CO2 required blood sample
flase, it does not require sampling or supervision
36
what is one limitation of c02 rebreathing method
One limitation is that exercise must be under steady-rate aerobic metabolism, restricting the method’s use during maximal and in the transition from rest to exercise
37
true or false: cardiac output varies considerably during rest
true
38
what are some influencing factors or cardiac output at rest
Influencing factors include emotional conditions that alter cortical outflow to the cardioaccelerator nerves and nerves that modulate arterial resistance vessels
39
how can emotional conditions influence CO at rest
they alter corticol outflow to the cardioaccelerator nerves
40
what is an avergae CO at rest for men
5 L
41
what is the average CO at rest for women
4L
42
men or women have a higher cardiac output at rest
MEN
43
CO is mostly affected by SV or HR
SV
44
what are heart rates and SV for resting athetles
Heart rates in healthy endurance athletes generally average 50 beats/min at rest while the resting stroke volume averages 100 mL
45
what are the 2 factors that explain the large stroke vol and low heart rate of endurance trained atheltes
Increased vagal tone and decreased sympathetic drive, both of which slow the heart
Increased blood volume, myocardial contractility, and compliance of the left ventricle, all of which augment the heart’s stroke volume (traiininng ventircular muscles to pump more)
46
true or false: endurance athletes dont need to pump as much to get the same CO
true
47
how are sarcomeres arranged for endurance traininng
in series (allow for larger SV)
48
how are sarcomeres arranged for resistnace training
iin parallel (smaller SV)
49
explain how cardiac output moves during exercise
Cardiac output increases rapidly during the transition from rest to steady-rate exercise and then gradually until it plateaus when blood flow meets the exercise metabolic requirements
50
when does cardiac output increase rapidly
during the transition from rest to steady state
51
when does CO plateau
when blood flow meets the exrcise metabilic requirements
52
know the cardiac output curve
.
53
The endurance athlete achieves a large maximal cardiac output how
solely through a large stroke volume at submaximal exercise
54
what are the 3 factors that increase SV during exercisee
1) increased preload
2) decreasd afterload
training adaptations that expand blood vol and ressistnace to blood flow
55
explain how icnreased preload leads to incrase in SV
Enhanced cardiac filling in diastole
followed by a more forceful systolic
contraction (frank starling)
56
explain how decraesed afterload/increased contractility increases heart SV
Normal ventricular filling with a
subsequent forceful ejection and
emptying during systole
57
true or false: training adaptations have no effect on stroke volume
false, Training adaptations that expand
blood volume and reduce resistance
to blood flow in peripheral tissues
58
what factors produce a greater preload during cardiac diastole phase
Any factor that increases venous return or slows down the heart will produce greater preload
59
an increase in end disstolic does what to the myocardial fibers
stretches them and initiates a powerful ejection stroke during contraction (ejects normal blood and additional)
60
what does frank starling law state
Frank-Starling law of the heart states that the force of
contraction of the cardiac muscle remains proportional
to its initial resting length
61
true or false: greater systolic ejection occurs despite increased resistance to blood flow and why
true beacsuse of exterice induced elevation of systolic bp
62
if there is an increased BP will there be greater systolic ejection or less
greater = more contractility
63
what enhances myocardial contractiole force
catacholine relrease in exercise
64
what is the fucntion of catacholine release in exercise
Catecholamine release in exercise enhances myocardial contractile force to augment stroke power and facilitate systolic emptying
65
true or false: the ventricles always contain functional residual blood bolume and why
true because it is easier to fill if blood is already in and does not allow the ventricles to collapse
66
during exercise there is an incrase in pressure in systemic circulation so what does the heart need to do to compensate and how does it do it>
heart must build up a higher diastolic pressure to pump blood against the higher resistance.
iwth more sympathetic innervation and catechline release, the heart will increase pressure and eject more blood despite increase in ressitance
67
what does cardiovascular drift describe
Describes the gradual time-dependent downward “drift” in several cardiovascular responses, most notably stroke volume with concomitant heart rate increase, during prolonged steady-rate exercise
68
ADD SLIDES ON CARDIOVASCULAR DRIFT
/
69
at rest, the typical cardiac output generally distributes by what locations
One fifth flowing to muscle tissue
The digestive tract, liver, spleen, brain, and kidneys receive major portions of the remaining blood
=depends on metabolic needs
70
most of cardiac output divers to where during exercise
to active muscles
71
most of the blood diversed to what portions of the muscle during exrceise
Most of the blood diverts to oxidative portions of muscle at the expense of those with high glycolytic capacity
72
for trained individuals, when does blood redistrubute begin
blood redistribution begins in the anticipatory period just prior to exercise
73
what causes blood to route to active muscles from areas that temporailry tolerate compromised blood flow
hormonal vascular regulation and local metabolic condiations
74
hormonal vascular regulation and local metabolic conditions cause blood to do what
to route to active muscles away from areas that temporailiy ttolerate compromised blood flow
75
blood redistribution among specfiic tisses occurs primarily during what
high intensity exercise
76
true or false: heart and brain tissue can tolerate a compromised blood supply
false
77
during redistribution, does blood even get redirected away from heart or brain
no , they cannot tolertate reduced blood flow
78
at rest, the myocardium uses what percentage of oxygen in the blood flowingn through coronary circulation
75%
79
what does it mean that tthe myocardium uses 75% of the oxygen
no backup, therefore if metabolic needs increase, you must increase blood flow sincne you are already taking up oxygen
80
durinng exercise, coronary circulation has what icnrease
4-5 fold icnrease
81
does cerebral blood flow ixnrease or decreaes during exercise
it icnrease (25-30% compared tp rest)
82
true or false: blood flow to heartt and brain decrease during exercise
false, it cannot tolerate that
83
what does an increase in max cardiac output produce
produces a proportionate increase in capacity to circulate oxygen and profoundly impacts an individual’s maximal oxygen consumption
84
what is the VO2 formulat
VO2 = CO x av VO2 diff
85
A low maximal oxygen consumption corresponds closely with whta
with a low maximum cardiac output
86
for every 1 L increase in o2 consumption aboce resting value, you get an icnrease or decrase in blood flow
5 to 6 L increase in blood flow
87
true or false: depending on the exercise mode, that will affect the oxugen consumption to blood flow relationship?
no
88
what provide distinguishing characteristics for preadolescent and adult endurance athletes
High levels of maximal oxygen consumption and cardiac output
89
An almost proportionate increase in maximum cardiac output accompanies what
increases in V·O2max with endurance training
90
how can you reach increase levels of oxygen consumpton
icnrease CO
91
true or false: Cardiac output and oxygen consumption remain linearly related during graded exercise for boys and girls and men and women
true
92
true or false and why Teenage and adult females exercise at any level of submaximal oxygen consumption with a 5-10% larger cardiac output than males
true due to a 10% lower hemoglobin concentration
93
do the higher heart rates in children during submaximal exrcise compensate for a smaller decreased volume
no
94
since kids have a smaller SV, they compensate with their HR
false cannot therefore they have a smaller cardiac output
95
since kids have a smaller SV and therefore a decrase CO what expands to meet the oxygen requirements
the a-VO@ difference expands
96
during rest what is the VO2 difference
5 ml of oxygen per dl of blood perfusing the tissue capilarry bed
97
during rest, we use alot of oxygen
false, we keep 75% of origial oxygen load bound to hemoglobinn
98
where is 75% of the bloods origian oxygen load remai nbound to
hemoglobin
99
why is there 75% of oxygen that remain in circulation at rest
because it keeps it as a back up incase you need to increase oxygen consumption nwithout icnrease CO
100
During maximum exercise, what does hemoglobin do
releases a considerable quantity of its “reserve” oxygen from blood that perfuses active tissues
101
What are the two factors tht increse oxygen consumption durinf exedtckse
increased CO
| expanded vo2 diff
102
The progressive expansion of the a-vO2 difference results from what
a reduced venous oxygen content
103
why dies The capacity of each deciliter of arterial blood to carry oxygen increases during exercise
from an increase in hemoconcentration
104
hemoconcentrationn results from what
Hemoconcentration results from the progressive movement of fluid from the plasma to the interstitial space with:
- increased in cap hydrostatic pressure as BP arries
- metabolic byproducts of exercise metabilise that osmotically draw flioe into tissue spaces from plasma
105
what interacts to increase oxugen extraction in active tissue during exrecise
central and peripheral factors
106
what are the central and peripheral factors icnrease oxygen extractionn inn active tissues during exrceise
A large portion of the cardiac output is diverted to active tissue
Some tissues temporarily decrease their blood supply to make more oxygen available
Exercise training redirects a greater portion of the central circulation to active muscle
An increase in skeletal muscle microcirculation
An increased capillary-to-fiber ratio
An increase in the size and number of mitochondria
Augmenting aerobic enzyme activity
Local vascular and metabolic improvements within muscle enhance its capacity to produce ATP aerobically
107
explai nthe factors effecting the execsinng aVO2 difference
.
108
The highest oxygen consumption during arm exercise averages BLANK lower than leg exercise
20 to 30%
109
IS MAXIMAL oxygen soncumption lower in arm por leg
leg
110
why is the oxygen consumption for arms lower
111
Arm exercise produces BLANK for heart rate and pulmonary ventilation
lower maximal values
112
WHY ARE There differences between arm and leg vo2
relate to the relatively smaller muscle mass activated in arm exercise
113
there are higher or lower oxygen consumption during arm exercise at all submaximal power outputs
higher
114
what are te 2 factors that produce additional oxygen cost at higher intensityies of arm execise
Lower mechanical efficiency in upper-body exercise from the additional cost of static muscle actions that do not contribute to external work
Recruitment of additional musculature to stabilize the torso during arm exercise
115
Any level of submaximal oxygen consumption or power output with upper-body exercise provides greater BLANK than lower-body exercise
physiologic strain than lower-body exercise
116
submaximal arm exersices produce higher...
Heart rates, pulmonary ventilations, perceptions of effort, and blood pressure
117
true or false: submaximal arm exrcised are good for cardiovascular patients
no because it increases bp and HR
118
why is there an elevated heart rate response durinng sibmaximal arm exrcises
Greater feed-forward stimulation from the brain’s central command to the medullary control center
Increased feedback stimulation to the medulla from peripheral receptors in active tissue
119
true or false: Exercise prescriptions based on running and bicycling do not apply to arm exercise
true
120
why can you not predict aerobic capacity for arm exercise based on a test that uses the legs and vice versa
becuase low correlations between vo2 max in arm and leg
121
what amplifies the specficicity concept
The lack of strong association between the two exercise modes amplifies the specificity concept
