Sinoatrial node of the next action potential. Pacemaker cells, however, don’t have this resting phase. Instead, immediately after one action potential, the membrane potential of these cells begins to depolarise again automatically, this is known as the pacemaker potential. Once the pacemaker potential reaches a set value, known as the threshold value, it then produces an action potential. Other cells within the heart (including the purkinje fibers and atrioventricular node; AVN) can also initiate action potentials; however, they do so at a slower rate and therefore, if the SA node is working, it usually beats the AVN to it. Outlined below are
Sentinel lymph node of false-negative with melanocytic staining. There are various advantages to the sentinel node procedure. First and foremost, it decreases lymph node dissections where unnecessary, thereby reducing the risk of lymphedema, a common complication of this procedure. Increased attention on the node(s) identified to most likely contain metastasis is also more likely to detect micro-metastasis and result in staging and treatment changes. Its main uses are in breast cancer and malignant melanoma surgery, although it has been used in other tumor types (colon cancer) with a degree of success. Other cancers which have been investigated with this technique are penile cancer,