Fisiologia

Cardiovascular

(Parte 3)

Efeito da tetrodotoxina em fibras de Purkinje

Fig. 23-2 Pressure-flow relationships in the coronary vascular bed. At constant aortic pressure, cardiac output, and

heart rate, coronary artery perfusion pressure was abruptly increased or decreased from the control level indicated

by the point where the two lines cross. The closed circles represent the flows that were obtained immediately after

the change in perfusion pressure; the open circles represent the steady-state flows at the new pressures. There is a

tendency for flow to return toward the control level (autoregulation of blood flow), and this is most prominent over

the intermediate pressure range (about 60 to 180 mm Hg). (From Berne RM, Rubio R: Coronary circulation. In

Handbook of physiology, sect 2, The cardiovascular system: the heart, vol I, Bethesda, Md, 1979, American

Physiological Society.)

Fig. 23-14 Effects of different stimuli on regional blood flow in the contralateral human cerebral cortex.

Sens 1, Low-intensity electrical stimulation of the hand; Sens 2, high-intensity electrical stimulation of the

hand (pain). (Redrawn from Ingvar DH: Brain Res 107:181, 1976.)