The cv system is involved in y transport of o2 and co2 y supply nutrients (ex. Substrates, h2o, minerals etc. ) y circulation of compounds such as hormones y waste removal (ex. urea) y regulation of blood flow y thermoregulation. Result y coordinated contraction of heart musculature to allow filling and emptying of blood. Cardiac output (q) ~ 4500 5000 ml/min. Control of the cv system: autonomous nervous system: Sympathetic control stimulates via release of norepinephrine from sympathetic nerve endings: increase in hr, sv, and q. Parasympathetic control - release of acetylcholine from nerve endings: decrease in hr, Increase in afferent nerve activity from mechano-receptors, increase in cns drive, resulting in an increase in q. Local vasodilation @ working tissue and an increase in the y thus vascular pressure is reduced at diastole during exercise to near resting values number of arterioles, reduces tpr.