hEY Everyone contribute ur Questions here and get to know regardin various questions any one planning for givin Exam in May ?
My ques..
a healthy 25 year old medical student has an exercise stress test at a local health club.which of the following is most likely to occur in this womans skeletal muscle during exercise.
a]decreased blood flow
b]decreased metabolite concentrations
c]increased arteriolar diameter.
d]increased oxygen conc
e]increased vascular resistance.
ans is c.
Blood flow can increaseas much as 20 fold in exercising skeletal muscle.This tremendous increase in blood flow results fromactions of local vasodilator substances on muscle arterioles.During exercise muscles use oxygen more rapidlythan it can b delivered by blood,which decreases O2 conc. in tissues[choiceD].The O2 deficiency causes vasodilator metabolites[choice B]such as co2, adenosine,lacticacid to accumulate in tissues.the vasodilator metabolites acting on arterioleslead to reduction in vascular resistance[choice e],&an increase in blood flow[choice a].