Action
There are five total papillary muscles in the heart, three in the right ventricle and two in the left. The anterior, posterior, and septal papillary muscles of the right ventricle each attach via chordae tendineae to the tricuspid valve. The anterior and posterior papillary muscles of the left ventricle attach via chordae tendineae to the mitral valve.
The papillary muscles of both the right and the left ventricles begin to contract shortly before ventricular systole and maintain tension throughout. This prevents regurgitation--backward flow of ventricular blood into the atrial cavities--by bracing the atrioventricular valves against prolapse--being forced back into the atria by the high pressure in the ventricles.
Read more about this topic: Papillary Muscle
Famous quotes containing the word action:
“Besides, our action on each other, good as well as evil, is so incidental and at random, that we can seldom hear the acknowledgments of any person who would thank us for a benefit, without some shame and humiliation. We can rarely strike a direct stroke, but must be content with an oblique one; we seldom have the satisfaction of yielding a direct benefit, which is directly received.”
—Ralph Waldo Emerson (1803–1882)
“Strange goings on! Jones did it slowly, deliberately, in the bathroom, with a knife, at midnight. What he did was butter a piece of toast. We are too familiar with the language of action to notice at first an anomaly: the ‘it’ of ‘Jones did it slowly, deliberately,...’ seems to refer to some entity, presumably an action, that is then characterized in a number of ways.”
—Donald Davidson (b. 1917)
“Therefore all just persons are satisfied with their own praise. They refuse to explain themselves, and are content that new actions should do them that office. They believe that we communicate without speech, and above speech, and that no right action of ours is quite unaffecting to our friends, at whatever distance; for the influence of action is not to be measured by miles.”
—Ralph Waldo Emerson (1803–1882)