oxygen delivery and circulator response to exercise Flashcards
1
Q
coronary arteries consist of two vessels ?
A
epicardial vessels andsubendocardial vessels
2
Q
which vessel is outside of the heart
A
epicardial vessels
3
Q
which vessels are inside of the heart
A
subendocardial vessels
4
Q
if a blockage to the epicardial vessels what happens to subendocaridal arterial plexus?
A
blood lost
5
Q
blood flow is greatest during diastole due to
A
decrease of muscle contraction therefore lack of pressure to close arteries allowing a greater blood flow
6
Q
cardiac muscle extracts 70 percent of the O2 coming to it at rest. why?
A
its always working
7
Q
to increase O2 delivery, blood flow must
A
increase
8
Q
systole occurs during which part of the EKG
A
ST segment
9
Q
ACh bind too this receptors of the endothelium causing them to release nitric oxide as a vasodilator substance
A
muscarinic
10
Q
SNS receptors and effects
A
- alpha1 (vasoconstriction)
- beta2 (vasodilation
11
Q
SNS has a direct stimulation - what are the hormones and where do they innervated?
A
- Ach - release NO, vasodilator
- NE - SNS, vasoconstriction
- Epi - humoral
12
Q
PSNS indirect stimulation
A
alteration in metabolic demand - producing more metabolites
13
Q
MVO2 =
A
Hr x SBP
14
Q
vasodilators are released from the cardiac cells in response to
A
low O2
15
Q
NO is released from coronary vessels in response to
A
shear stress
16
Q
locally derived vasodilators
A
- adenosine
- ADP & AMP
- K+
-H+ - CO2
- prostaglandins
- NO
17
Q
what stimulates NO release
A
shear stress
18
Q
high shear stress may occur when you have
A
plaque build up (thrombus)
19
Q
other NO functions
A
- decrease in platelet activation and aggregation
- decrease vascular smooth muscle cell proliferation
- decrease adhesion molecule expression
- decrease oxidation of LDL
20
Q
decrease platelet activation and aggregation results in
A
decreases thumbs formation int eh material wall
21
Q
decrease vascular smooth muscle cell proliferation results a
A
decreases thickening and stiffening of the artery
22
Q
decrease in adhesion molecule expression results in
A
DCAM1 - immune cells
23
Q
decrease of oxidation of LDL results
A
atherosclerosis
24
Q
double product =
A
Heart rate x systolic BP
25
blood flow oscillates in cardiac and skeletal muscle as a result of muscle contraction? true or false
true
26
increased O2 demand
-increase blood flow
- increase O2 extraction
27
increase blood flow results
- increase CO
- redistrubte blood
28
increase O2 extraction results
- open more capillaries
29
increase of cardiac output due to
- increase HR
- increase SV
30
Max HR =
208 - (.7xAge)
31
increased SV =
- increase, then plateau at 40 to 60% VO2 max
- no plateau in highly trained subjects (better venous return)
32
the plateau in SV that occurs in the untrained at 40 to 60% of VO2max is due to
decreased in filling time
33
total of _____ of blood to be circulate dhtorught the entire body at rest
5 to 6 L
34
why is there a need of redistribution of blood flow during exercise
- increased blood flow to working skeletal muscle
- less blood flow to less active organs
35
percent of blood flow to SM at rest and during maximal exercise
- at rest 15 to 20%
- max 80 to 85%
36
maximal cardiaci output
20-30 L/min of blood to be circulated at maximal exercise
37
the increase in muscle blood flow that occurs during exercise is regulated by several factors that promote
vasodilation
38
autoregulation is
- blood flow increased to meet metabolic demands of tissue
- due to changes in O2 tension, CO2 tension, nitric oxide, potassium, adenosine, and PH
39
why have vasoconstriction
to visceral organs and inactive tissues?
- stimulated by SNS vasoconstriction
- decrease blood flow to 20 to 30$ of resting values to SM
40
the local inhibition of sympathetic induced vasoconstriction that occurs during exercise is called
sympatholysis
41
produce of No, ATP, prostaglandins is the promotion of dilation which then
increases smooth muscle relaxation in the arterioles
42
ATP and adenosine are important vasodilators for
they increase muscle blood flow during exercise
43
what does adrenergic stimulation do?
constricts the arteriole at rest limiting the amount of blood flow to the muscle
44
true or false: only 50-80% of the pre capillary sphincters are open at rest
true
45
as intensity increases, motor units increases, what happens to capillaries
more created to match metabolic demand
46
local factors to cause arterioles/metarterioles to open
- decreased O2
- increased CO2
-H+
- increased NO
- Adenosine
- prostaglandins
47
humoral control that causes the arterioles/metaarteroles to open
epinephrine
48
active hypermia
the increase in blood flow secondary to metabolites
49
overcoming the SNS vasoconstriction with active hyperemia is referred to as
functional sympatholysis
50
cardiac muscle extracts _____ of the O2 in the blood at rest
70%
51
skeletal muscle extracts ___% of the O2 in the blood at rest
22%
52
O2 uptake in skeletal muscle increases as a result of (2)
- an increase in blood flow
- an increase in O2 extraction from the blood
53
arteriovenous difference is the (a-VO2 diff)
arterial oxgen centent minus the venous O2 content
54
changes in arteriovenous difference depends on
- myoglobin
- capillarity
- mitochondria
- mitochondria enzymes
55
to meet the increased oxygen demand of the skeletal muscles during exercise, it is necessary to?
increase muscle blood flow hwoile reducing blood flow to less active organs
56
the arterioles in skeletal muscle have a high vascular resistance at rest due to
adrenergic sympathetic stimulation
57
adrenergic sympathetic stimulation causes
arteriole smooth muscle to contact (vasoconstriction)
58
what is VO2max
maximal oxygen consumption
59
what is maximal aerobic capacity
the maximal amount of physiological work that an individual can do as measured by oxygen consumption
60
Fick equation
VO2 = Q x (a-v-)O2 diff
61
what limits VO2max?
stroke volume
62
incremental exercise affects HR and CO by
- increases linearly with increasing work rate
- reaches plateau at 100% VO2 max
63
incremental exercise affects on blood pressure
- mean arterial pressure increases linearly
- systolic BP increases
- diastolic BP remains fairly constant
64
what happens to BP as CO increases
BP increases
65
why does diastolic not increase when incremental exercise increases?
due to TPR - vasodilation will cause a lower TPR
66
elevated HR and BP in emotionally charged environment due to
increases in SNS activity
- can increase pre exercise
- does not increase peak HR or BP during exercise
67
during an emotional state, which could cause an increase of HR and BP. What is the steps of that happening?
increase of stress stimulates the brain to release NE/E due to its purpose of fight or flight response. these hormones further enhance the sympathetic stimulation of the heart, blood vessels. therefore increase in HR and BP
68
at the onset of exercise: what happens?
- rapid increase in HR, SV, and cardiac output
- plateau in submaximal (below lactate threshold) exercise)
69
what happens during recovery after an exercise
- decrease in HR, SV, and cardiac put toward resting levels
- this depends on: duration and intensity of exercise and training state of subject
70
intermittent exercise recovery heart rate and blood pressure between bouts deepens on
- fitness level
- temperate and humidity
- duration and intensity of exercise
71
heavy intensity intermittent exercise
near maximal Hr values are possible
72
During arm and leg exercise, which causes a higher heart and blood pressure?
arm
73
why does your arm have a higher heart rate and blood pressure?
theres a greater sympathetic outflow to the heart during arm work when compared to leg exercise
74
the large increase in blood pressure during arm work is due to
vasoconstriction in the active muscle groups
75
larger muscle groups (leg) that is exercising causes more resistance vessels to dilate. therefore causing?
lower peripheral resistance causing lower blood pressure
76
at the same oxygen uptake, arm work results in higher HR and BP due to
- due to higher sympathetic stimulation
- due to vasoconstriction of large inactive muscle mass
77
during a prolonged exercise cardiac output is maintained because of
- a gradual decrease in stroke volume due to dehydration and reduce plasma volume
78
The increase in heart rate and decrease in stroke volume observed during prolonged exercise is often referred to as
cardiovascular drift
79
supine vs upright exercise
supine exercise have a much greater venous return and Higher SV and lower HR
80
the central command refers to
a motor signal developed within the brain -
81
fine tuned by feedback from
- heart mechanoreceptors
- muscle mecnachorecepotrs
- muscle chemoreceptors
- baroreceptors
82
muscle chemoreceptors are sensitive to increases in
muscle metabolites (potassium, lactic acid)
- exercise pressor reflex
83
what is exercise pressor reflex
its a type of peripheral feedback to the cardiovascular control center (medulla oblongata)
84
muscle mechanoreceptors are sensitive to
force and speed of muscular movement (muscle spindles, GTOs)
85
baroreceptors are sensitive to
changes in arterial blood pressure
86
what proposes that the initial signal to “drive” the cardiovascular system at the beginning of exercise comes from higher brain centers.
central command theory
