Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Exercise & Environment > Cardiovascular and respiratory responses to exercise > Flashcards

Cardiovascular and respiratory responses to exercise Flashcards

1
Q

types of exercise

A
  • dynamic or isometric
  • aerobic or anearobic
  • large muscle mass or small muscle mass
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what could everyday tasks be classified as for patients with cardiorespiratory diseases

A

high-intensity or maximal exercises

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

VO2

A

oxygen consumed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

VCO2

A

carbon dioxide produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how is VO2 and VCO2 determined in exercise

A

amount of muscle activity

blood flow & ventilation are coupled to metaboliism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what determines method of ATP maintenance?

A
  • metabolic status

- energy requirements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happens to VO2 during exercise

A

increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

who will have greatest VO2max

A

highly trained atheletes

- endurance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

tidal volume during exercise

A
  • increases as minute ventilation increases
  • increases linearly up to 6 times resting value
  • will level off at ~50% vital capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what maintains gaseous exchange at all times

A

residual lung volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why is there always residual lung volume

A

to allow for gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is residual lung volume

A

air in the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how are elevated pulmonary ventilations achieved

A
  • linearly increases in tidal volume

- non-linear increases in breathing rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

when does ventilation response to exercise

A

synchronous with exercise onset

  • not a reflex response to altered chemistry
  • not feedback mechanism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

humoral changes during exercise

A
  • adrenaline released from adrenal medulla
  • induces vasoconstriction at viscera
  • vasodilation at skeletal muscle
  • increases heart rate
  • bronchodilator
  • glycogenolysis in liver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what happens to K during exercise

A

K from depolarised muscle cells can increase to levels considered dangerous if muscles were at rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

PaCO2 and PaO2 during exercise

A

change very little if at all.

  • PaO2 may rise a little due to decreased PaCO2 or fall due to limitation in diffusion
  • PaCO2 will fall a little at high VO2 as pH increases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

One of the most important observations in ventilatory response to exercise

A

expected rise in PACO2 does not occur with rise in metabolism during exercise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

PACO2

A

partial pressure of alveolar gas

Alveolar are close to arterial blood sample so good measure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

PACO2

PaCO2

A

PACO2 partial pressure alveolar gas

PaCO2 partial pressure arterial gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

4 hypotheses for regulation of respiratory responses to exercise

A
  1. central command or feedforward must account for at least fast component of response
  2. afferent signals from muscles passing up spinal chord my produce feedback control - dog experiments support this but paraplegics don’t
  3. signals from peripheral chemoreceptors detecting pH changes play some role. Even though PACO2 remains constant, slight oscillations may be detected, or changes in sensitivity. But their removal only mildly alters phase 2
  4. lactate, potassium and adrenaline all stimulate peripheral chemoreceptors and may play a role
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

respiratory responses work in

A

parallel

- if one signal is removed, the others will work to compensate and keep respiration rate constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

change in blood flow during exercise

A

changes from spending 0.8 seconds in pulmonary capillary at rest to only 0.2 seconds during exercise

  • less time to load oxygen
  • large reserve usually sufficient to complete oxygenation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

changes in cardiac output

cardiocentric

A

from 5l/min at rest up to 30l/min in intense exercise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

cardiac output =

cardiocentric

A

heart rate x stroke volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

changes in heart rate during exercise

A

HR often rises with one beat during transition from rest to work = before feedback could do so

  • provides evidence for central command or feedforward
  • increases rapidly in first 10-20 secs then slowly increase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what provides evidence for feedforward or central command of response to exercise

A

HR increases within one beat of onset, which is too quick for feedback mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

frank-starling’s mechanism showing cardiac output matched to demand

A
  • heart automatically pumps all venous return back to arteries
  • dog’s exercise performance was not impaired by cardiac denervation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

cardiac output =

tissuecentric

A

(arterial BP - central venous BP)/ total peripheral resistance

  • arterial BP ~90mmHg
  • central venous BP ~3mmHg
    TPR can be changed to alter CO without changing BP
30
Q

changes in cardiac output

tissuecentric

A

total peripheral resistance is altered to change flow/CO without changing BP

31
Q

precapillary sphincters

A
  • functional unit of the capillary bed with precapillary branching off directly from the arteriole
  • important for directing blood to tissue that need it most and reducing blood flow to inactive tissues
  • needed ‘cus limited blood
32
Q

muscle vasodilation during exercise

A
  • resting muscle has a low blood flow and only a few capillaries open at a time
  • exercise causes more capillaries to open, higher blood velocity & double the fall in oxygen saturation
  • muscle oxygen consumption can increase more than 40 times
  • capillary recruitment also reduces diffusion distance
33
Q

blood flow in resting muscle

A
  • resting muscle has a low blood flow and only a few capillaries open at a time
34
Q

what changes blood flow in muscle during exerise

A

vasodilation

35
Q

changes to muscle capillairies in exercise

A
  • capillary recruitment
  • more capillaries open
  • higher blood velocity
  • double fall in oxygen saturation
    = muscle oxygen consumption increase more than 40 times
36
Q

muscle oxygen consumption during exercise

A

can increase more than 40 times

37
Q

blood flow redistribution during exercise

A

CO increases with exercise intensity and blood flow is redistributed

  • skeletal muscle large proportion
  • skin blood flow increases for thermoregulation
38
Q

changes in blood flow to skin during exercise

A

rest: 9% 500ml
light exercise 16% 1500ml
heavy exercise: 12% 1900ml

39
Q

changes in blood flow to skeletal muscle during exercise

A

rest: 21% 1200ml
light exercise 47% 4500ml
heavy exercise: 71% 12500ml

40
Q

what exercise types changes BP most

A

heavy resistance magnifies change in BP more compared to dynamic aerobic

41
Q

changes in BP and HR in isometric exercise

A
  • hand grip at 30% maximal voluntary contraction
  • modest HR increase
  • large BP increase
42
Q

changes in BP and HR in dynamic exercise

A
  • large HR increase to maximal values

- little change in BP

43
Q

CV control during exercise

A

controlled by autonomic nerve supply :

  • parasympathetic
  • sympathetic
  • adrenaline
44
Q

autonomic nerve supply to the heart =

A
  • parasympathetic
  • sympathetic
  • adrenaline
45
Q

parasympathetic control of heart during exercise

A

via vagus nerves, which act via muscarinic acetylcholine receptors
- mainly produce bradycardia

helps to slow the increased HR

46
Q

sympathetic control of heart during exercise

A
  • via the superior, middle and inferior nerves via beta 1 adrenoreceptors
  • produce tachycardia and increased contractility
  • releases neurotransmitter noradrenaline
47
Q

control of circulating adrenaline on heart during exercise

A
  • circulating adrenaline from medulla
  • also act of beta 1 adrenoreceptors
  • tachycardia and increase contractility
48
Q

what do afferent signals do to heart during exercise

A

strong evidence they play a part in feedback control of HR and BP
K+ and H+ are probably sense in the muscle

49
Q

what does evidence suggests may also play a role in controlling BP and HR

A

afferent signals from muscle involved in feedback control, most likely from sensing K+ and H+ in muscle

50
Q

tachycardia

A

abnormally rapid heart rate

51
Q

bradycardia

A

abnormally slow heart rate

52
Q

summary of CV responses to exercise

A
  • peripheral circulation determines venous return by controlling the perfusion of each tissue
  • the heart matches cardiac output to venous return
  • blood pressure response depends on the kind, duration and intensity of exercise
  • there is evidence for central command, feedforward & humeral mechanisms that are all integrated to regulate responses
53
Q

variations of VMAX

A
  • generally lower in women than men
  • tends to increase up to the of 20
  • slowly declines after 20 yrs
  • maintaining active lifestyle can delay decrease
  • results vary by testing method
  • often greater in load bearing exercises
54
Q

what can VMAX indicate

A

long-term energy system capacity

55
Q

method of VMAX measurement

A

increments exercise test to exhaustion
e.g on a treadmill
method of testing should be tailored to indivual requirement. e.g running for a runner, cycling for a cyclist

56
Q

what is H+ from exercise buffered by

A

bicarbonate

57
Q

glycolysis during exercise causes increases in

A

lactate and H+

58
Q

how is H+ buffered

A

H+ + HCO3 -> H2CO3 -> CO2 + H2O

  • needs presence of carbonic anhydrase
59
Q

when does minute ventilation increase disproportionately to VO2

A

ventilatory threshold

When lactate and H+ begin to increase and buffered by bicarbonate and CA

60
Q

what does the ventilatory threshold predict

A

lactate threshold, from the ventilatory response during incremental exercise

61
Q

what happens to majority of lactate at lower outputs

A

pyruvate dehydrogenase and shuttle system enzymes metabolise the majority

62
Q

what happens lactate at higher power outputs

A
  • ATP demands exceed aerobic provisions
  • glycolytic flux must increase
  • therefore lactate production is increased
  • lactate is increased at greater rate than it can be metabolised
  • lactate accumulates in venous blood
    = lactate threshold
63
Q

what is considered a high power output

A

> 60% VO2max

64
Q

lactate threshold

A

when lactate is produced at a greater rate than shuttle system enzymes and pyruvate dehydrogenase can metabolise it. Occurs at high power exercise, when glycolysis used for energy bc ATP provisions are insufficent

65
Q

what limits exercise

A
  • CV performance is the usual limit not CR
  • ventilatory flows are usually lower than highest attainable value
  • partial pressure of oxygen; even though muscle mitochondria can work at as low as 0.15kpa, there must be a diffusion gradient from blood to cell
  • VMAX corresponds with HR
66
Q

example VT

A

3.04L/min

67
Q

example LT

A

43.5 ml/kg/min

68
Q

Effects of training on CR response

A
  • increase total lung capacity to more than 8l e.g endurance divers, wind musicians
  • increase VO2max to more than 85ml/kg/min
  • decrease resting HR to less than 40bpm
  • increase stroke volume from bigger heart, trained muscle!!
69
Q

how does diffusing capacity for oxygen at rest change with training

A

doesnt

70
Q

max stroke volume changes with training

ml

A

normal: 104
training: 120
olympians: 167

71
Q

max CO changes with training

ml

A

normal: 30
training: 23
olympian: 30

72
Q

VMAX changes with training

l/min

A

normal: 3
training: 4.2
olympian 5.4

Exercise & Environment (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions