Parasympathetic signals via the Vagus nerve serve to slow the rate, while sympathetic nerve signals speed up the rate, the intrinsic rate is normally slowed to give a natural frequency of 70 BPM. ... Sympathetic innervation of the heart serves to speed up the heart and increase the stroke volume. ... There exists a mechanism by which the heart and the lungs do not expand at the same time so as not to limit the volume performance of either one, when inspiration occurs, the heart rate slows to allow the lungs to reach their maximum capacity. ... The duration of systole is lessened, whi...

• Word Count: 1504
• Approx Pages: 6
• Grade Level: Undergraduate