L9 - Integrative and vascular responses to exercise.

Question 1

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

Answer 1

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.

Question 2

how does the distribution of blood change in exercise

Answer 2

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

Question 3

what is the purpose of local control of arteriolar tone

Answer 3

Ensure that local perfusion matches tissue’s demand.

Question 4

how do we control arteriolar tone? (4)

Answer 4

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.

Question 5

how do the control of arteriol tone operate ?

Answer 5

negative feedback.

Question 6

how local muscles determine the blood flow.

Answer 6

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

Question 8

extrinsic control of arteriolar tone. purpose and mechanisms

Answer 8

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.

Question 9

what SBP estimate

Answer 9

work of heart
strain against arterial walls
appropriate cardiovascular function.

Question 10

what does DBP estimate ?

Answer 10

estimates peripheral resistance.

Question 11

what can myocardial workload and its vo2 be estimated from?

Answer 11

Rate pressure product (RPP) = SBP * HR.

Question 12

RPP at rest vs exercise

Answer 12

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

Question 13

explain blood pressure relationship with exercise intensity.

Answer 13

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

Question 14

blood pressure in arm versus leg exercise.

Answer 14

aterial BP increase more w arm, same with HR.

Question 15

oxygen extraction in arm versus leg exercise.

Answer 15

decrease w arm

Question 16

SV in arm versus leg exercise.

Answer 16

decrease w arm.

Question 17

glucose usage in arm versus leg exercise.

Answer 17

increase w arm exercise

Question 18

what does rise of BP depend on for resistance training.

Answer 18

the valsalva manouevre
muscle mass contracted
duration of contraction
MVC%

Question 19

blood pressure and recovery…

Answer 19

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

Question 20

3 controls for cardiovascular during e

Answer 20

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.

Question 21

cardiovascular control at rest.

Answer 21

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.