BLG 10A/B Lecture Notes - Lecture 17: Brachial Veins, Brachial Artery, Radial Artery
Document Summary
Muscular pump: valves prevent backflow of the blood, veins are inherently moving blood back to the heart and contribute to venous return. Sv = edv-esv rearrange and substitute to get: map = co x tpr = hr x (edv-esv) x tpr (fig 19. 9) Co is very sensitive to changes in edv due to frank-starling forces stretch of the heart by blood volume that mechanically aligns actin and myosin. Edv is dependent on venous return (vr) per cycle ideally total amount leaving heart = total amount coming into heart: co = vr. Baroreceptor reflex: a quick and efficient way to decrease pressure. Vascular stretch and deformation firing as map firing rate of baroreceptors threshold for excitation = 50 mmhg maximum firing at ~200 mmhg sensitivity can be altered. With hypertension due to stiffness of sinus and/or aorta response to firing of baroreceptors (fig 19. 10) Venoconstriction = venous compliance and vr, therefore edv.
