How do you draw and explain how the heart contracts with a before and after picture.? - working out picture before after
and how the SA node, etc. work?
Web site or the answer would be great, thanks!
Sunday, February 7, 2010
Working Out Picture Before After How Do You Draw And Explain How The Heart Contracts With A Before And After Picture.?
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I have a fairly detailed description below and left. The third term is a video. Hope this helps.
To maximize the efficiency of contraction and cardiac output, cardiovascular system:
Helmet important for the ventricular late. This allows the atria completely empty their contents into the ventricles would fill the contraction of inefficient and anti-repression. The atria are electrically insulated from the chamber, only through the AV node, connected to the short delays the signal.
The coordinated contraction of ventricular cells. The chambers must maximize systolic blood pressure of blood through the circulatory force, so that all cells need to work together in the ventricle.
Ventricular contraction starts at the top of the heart, the blood in the large arteries of force. The contraction that the blood is in production squeezes more efficient than a withdrawal from all directions. Although ventricular pacing originates from the AV node cond in the dividing wall between the atria and ventricles, the His bundleproduced signal at the top.
The depolarization spreads to the heart muscle very quickly. The cells of the ventricles contract almost simultaneously.
Action potentials of cardiac muscle is not normal and important. This prevents a premature relaxation, maintaining the initial contraction, until the entire myocardium time to depolarization and contract was.
No tetany. After the adjustment, close the heart to relax again. Continued contraction of the heart, without rest would be fatal, which is prevented by a temporary disablement of certain ion channels
SA node
The signals from the SA node stimulate the atria to contract and travel conditions through the AV node. After a delay, the impulse is conducted through the bundle of Purkinje fibers and endocardium at the apex of the heart, and finally the ventricular epicardium.
Microscopically, the wave propagates the depolarization of neighboring cells through gap junctions in the intercalated disk is located. The heart is a syncytium: electrical impulses that travel freely between the cellss in each direction, so that the functions of myocardial contraction as a unit. This feature enables the rapid, synchronous depolarization of the heart muscle. While beneficial in general, this property can be detrimental, because it potentially allows for the dissemination of false electrical signals. These obligations can be closed to isolate the damaged tissue or die, such as myocardial infarction (heart attack)
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