Unformatted text preview: e venous valves - these valves are located within the lumen of large veins and prevent the backflow of venous blood (Figure 10-3 Without venous valves, contracted skeletal muscle would squeeze blood both towards and away from the heart. With venous v respiratory activity - the pressure within the chest cavity transiently decreases by approximately 5 mm of Hg during respiration . cardiac suction - during ventricular contraction the atrial cavities are enlarged slightly and this causes a transient reduction of a...
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- Fall '08