You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Which cells are referred as "Pacemaker cells" with relation to 'BER'? and explain in detail?
Interstitial cells of Cajal Basic Electrical Rhythm (BER): Smooth muscle cells of the gastrointestinal tract have spontaneous rhythmic fluctuations in membrane potential between about -65 and -45 mV. BER initiated by Pacemaker cells called "Interstitial cells of Cajal". Pacemaker cells - Interstitial cells of Cajal. Stellate mesenchymal cells with smooth muscle-like features. Location: Are absent in esophagus & proximal stomach. In distal stomach & small intestine - Located in outer circular muscle layer near myenteric plexus. In colon - Located at the submucosal border of circular muscle layer. Frequency: In Stomach & small intestine - Pacemaker frequency is in descending gradient. Pacemaker with the highest frequency usually dominates (Eg., In Hea).