L9 - Integrative and vascular responses to exercise. Flashcards
the affect of oxygen extraction (a-vo2 difference) with exercise intensity. and what is this due to
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.
how does the distribution of blood change in exercise
more blood flow in general. Redistribution of blood at exercise so that our muscles and heart get much more.
what is the purpose of local control of arteriolar tone
Ensure that local perfusion matches tissue’s demand.
how do we control arteriolar tone? (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.
how do the control of arteriol tone operate ?
negative feedback.
how local muscles determine the blood flow.
increase all things to ensure they can get blood flow. small change in radius causes large change in flow.
extrinsic control of arteriolar tone. purpose and mechanisms
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.
what SBP estimate
work of heart
strain against arterial walls
appropriate cardiovascular function.
what does DBP estimate ?
estimates peripheral resistance.
what can myocardial workload and its vo2 be estimated from?
Rate pressure product (RPP) = SBP * HR.
RPP at rest vs exercise
~6000 at rest, to ~40,000 at exercise. (higher with resistance and upper body strength)
explain blood pressure relationship with exercise intensity.
remember lab report!
diastolic lower/stay the same whereas SBP increases (more with resistance).
blood pressure in arm versus leg exercise.
aterial BP increase more w arm, same with HR.
oxygen extraction in arm versus leg exercise.
decrease w arm
SV in arm versus leg exercise.
decrease w arm.
glucose usage in arm versus leg exercise.
increase w arm exercise
what does rise of BP depend on for resistance training.
the valsalva manouevre
muscle mass contracted
duration of contraction
MVC%
blood pressure and recovery…
BP after submax decreases below pre-e vaules for both normotensive and hyertensive people (<12 hours)
treatment for hypertension.
3 controls for cardiovascular during e
- feedforward central command (dominates early). immediate jump of HRm- PNS inhibition.
- Ergoreceptors important. in attaining then maintaining plateau, esp. for increase BP, so is called a “pressor” response.
- baroreceptors (-ve feedback) reset to a higher level within seconds of exercise onset, less important at rest.
cardiovascular control at rest.
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.