L9 - Integrative and vascular responses to exercise. Flashcards

1
Q

the affect of oxygen extraction (a-vo2 difference) with exercise intensity. and what is this due to

A

from 25% extraction at rest to 90% in max exercise.

redistribution of blood. taken to the active muscles.

increase metabolic activity of muscles therefor there is more of a need more oxygen in muscles.

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2
Q

how does the distribution of blood change in exercise

A

more blood flow in general. Redistribution of blood at exercise so that our muscles and heart get much more.

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3
Q

what is the purpose of local control of arteriolar tone

A

Ensure that local perfusion matches tissue’s demand.

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4
Q

how do we control arteriolar tone? (4)

A

Myogenic - abilityof our arterioles ot constrict, when blood pressure is high they can constrict to restore stable blood flow.

temperature - most vessels will dilate w heat to get more blood. muslces will be protective and make sure blood gets to them.

metabolic - dilate with increase co2, h+, K+ adenosine, decease PO2. so that they can exchange things with local tissue.

Humoral - NO in response to hypoxia and shear stress. Histamine dilate during inflammatory reaction.

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5
Q

how do the control of arteriol tone operate ?

A

negative feedback.

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6
Q

how local muscles determine the blood flow.

A

increase all things to ensure they can get blood flow. small change in radius causes large change in flow.

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7
Q
A
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8
Q

extrinsic control of arteriolar tone. purpose and mechanisms

A

purpose - MAIN to ensure maintenance of MAP. also to ensure adequate perfusion of active tissues, espically under stress (e).

neural and endocrine

neural: SNS releasing noradrenaline onto arterioles.

Endocrine: ADH and ANG-II from adrenal medulla SNS.

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9
Q

what SBP estimate

A

work of heart
strain against arterial walls
appropriate cardiovascular function.

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10
Q

what does DBP estimate ?

A

estimates peripheral resistance.

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11
Q

what can myocardial workload and its vo2 be estimated from?

A

Rate pressure product (RPP) = SBP * HR.

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12
Q

RPP at rest vs exercise

A

~6000 at rest, to ~40,000 at exercise. (higher with resistance and upper body strength)

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13
Q

explain blood pressure relationship with exercise intensity.

A

remember lab report!
diastolic lower/stay the same whereas SBP increases (more with resistance).

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14
Q

blood pressure in arm versus leg exercise.

A

aterial BP increase more w arm, same with HR.

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15
Q

oxygen extraction in arm versus leg exercise.

A

decrease w arm

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16
Q

SV in arm versus leg exercise.

A

decrease w arm.

17
Q

glucose usage in arm versus leg exercise.

A

increase w arm exercise

18
Q

what does rise of BP depend on for resistance training.

A

the valsalva manouevre
muscle mass contracted
duration of contraction
MVC%

19
Q

blood pressure and recovery…

A

BP after submax decreases below pre-e vaules for both normotensive and hyertensive people (<12 hours)
treatment for hypertension.

20
Q

3 controls for cardiovascular during e

A
  1. feedforward central command (dominates early). immediate jump of HRm- PNS inhibition.
  2. Ergoreceptors important. in attaining then maintaining plateau, esp. for increase BP, so is called a “pressor” response.
  3. baroreceptors (-ve feedback) reset to a higher level within seconds of exercise onset, less important at rest.
21
Q

cardiovascular control at rest.

A

negative feedback of

short term - arterial pressure. detected by aortic and carotid baroreceptors. causes SNS and PNS mediated responses.

long term - venous pressure. detected by cardiopulmonary baroreceptors. causes mainly endocrine and renal responses.