Question

Capillary perfusion of the tissues is intermittent and is regulated, in part, by the level of vascular resistance provided by the precapillary sphincter. Local vascular resistance will (check the true statements; 12 points):

a.         increase if local pH increases.

b.         increase if local tissue P_O2 decreases.

c.         decrease if local concentrations of adenosine increase.

d.         increase if local P_CO2 increases.

e. x    decrease if there is an increase in O₂ utilization.

f.          increase if the sympathetic system is stimulated.

Answer 1

Ans:+

concept :- when there is deficiency of oxygen or increase co2 at tissue level the precapillary sphicters dilate decreaeasing the vascular resistance.

and Vic - versa.

Hydrogen ion increases when CO2 increases or during states of increased anaerobic metabolism, which can produce metabolic acidosis. Like CO2, increased H+ (decreased pH) causes vasodilation

a) True

Because local pH increase means less less conc of CO2 . Means vasoconstriction--.inc vascular resistance

B) False

Po2 decreaeas means PCO2 increase --- acidosi -- vasodilation.-- Dec vascular resistance

C) False

Because adenosine is a vasoconstor.

D)False

When local PCO2 Inc --- more acid --- more vasodilation.

E) True

Because as more oxygen is needed so there must be vasodilation.

F) true

Sympathetic system cause vasoconstriction