Avtor/Urednik		Starc, Vito
Naslov		Effects of myogenic and metabolic mechanisms on the autoregulation of blood flow through muscle tissue: a mathematical model study
Tip		članek
Vir		Cardiovasc Eng
Vol. in št.		Letnik 4, št. 1
Leto izdaje		2004
Obseg		str. 81-8
Jezik		eng
Abstrakt		Mathematical modeling of mechanisms responsible for autoregulation have been thoroughly studicd in the past. Less attention was, however, paid on the simultaneous action of different mechanisms, particularly during increased need for blood flow such as with increased metabolic activity or hypoxia. Here we present simultaneous effects of the myogenic and metabolic mechanisms of autoregulation. In the model the microvascular network was divided into three segments, each with the characteristic lumped resistance. The arterial resistance exhibited myogenic properties with the resistance linearly increasing as the transmural pressure departed from that in the resting conditions. The capillary resistance changed with the oxygen concentration in the venous blood. Finally, the venous and the arteriolar resistance both depended on the blood flow and were reduced with increased flow. The described network resistance led to a pressure flow relationship, which was used to fit the published experimental data of the perfused hind limb of a dog obtained in conditions of changed perfusion pressure, hypoxic conditions or during increased metabolic activity. By variation of the parameters we further studied their influence on the autoregulatory blood flow as well as on the venous blood 0: concentration and the capillary pressure. We found that the metabolic component primarily changes the resistance of the network during increased metabolic activity or hypoxia. The myogenic component not only maintains blood flow despite changes in the perfusion pressure but also helps in facilitating blood flow either during the increased metabolic activity or hypoxic conditions.
Deskriptorji		MUSCLES HOMEOSTASIS VASCULAR RESISTANCE OXYGEN ANOXIA DOGS OXYGEN CONSUMPTION HINDLIMB MUSCLE CONTRACTION BLOOD FLOW VELOCITY COMPUTER SIMULATION