Atrioventricular node the crista terminalis, and anteriorly, via the interatrial septum. Contraction of heart muscle cells requires depolarization and repolarization of their cell membranes. Movement of ions across cell membranes causes these events. The cardiac conduction system (and AV node part of it) coordinates myocyte mechanical activity. A wave of excitation spreads out from the sinoatrial node through the atria along specialized conduction channels. This activates the AV node. The atrioventricular node delays impulses by approximately 0.09s. This delay in the cardiac pulse is extremely important: It ensures that the atria have ejected their blood into the ventricles first before the ventricles
Lymph node biopsy enlargement (swollen glands or lymphadenitis). It may also determine whether tumors in the lymph node are cancerous or noncancerous. Enlarged lymph nodes may be caused by a number of conditions, ranging from very mild infections to serious malignancies. Benign conditions can often be distinguished from cancerous and infectious processes by microscopic examination. The pathologist may also perform additional tests on the lymph node tissue to assist in making a diagnosis. Some of the conditions where abnormal values are obtained are: Lymph node biopsies may be performed to evaluate the spread of cancer. See Lymphadenectomy#With_sentinel_node_biopsy. However, Sentinel lymph node biopsy for