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