Changes in The Cardiac Function Curve
In vivo however, extrinsic factors such as an increase in activity of the sympathetic nerves, and a decrease in vagal tone cause the heart to beat more frequently and more forcefully. This alters the cardiac function curve, shifting it upwards. This allows the heart to cope with the required cardiac output at a relatively low right atrial pressure. We get what is known as a family of cardiac function curves, as the heart rate increases before the plateau is reached, and without the RAP having to rise dramatically to stretch the heart more and get the Starling effect.
In vivo sympathetic outflow within the myocardium is probably best described by the time honored description of the sinoatrial tree branching out to Purkinges fibers. Parasympathetic inflow within the myocardium is probably best described by influence of the vagus nerve and spinal accessory ganglia.
Read more about this topic: Cardiac Function Curve
Famous quotes containing the words function and/or curve:
“The function of literature, through all its mutations, has been to make us aware of the particularity of selves, and the high authority of the self in its quarrel with its society and its culture. Literature is in that sense subversive.”
—Lionel Trilling (1905–1975)
“I have been photographing our toilet, that glossy enameled receptacle of extraordinary beauty.... Here was every sensuous curve of the “human figure divine” but minus the imperfections. Never did the Greeks reach a more significant consummation to their culture, and it somehow reminded me, in the glory of its chaste convulsions and in its swelling, sweeping, forward movement of finely progressing contours, of the Victory of Samothrace.”
—Edward Weston (1886–1958)