This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Pacemakers of the GIT are present in all, EXCEPT: 
Select and explain. 
A. Cardiac end of stomach, B. Pyloric end of stomach, C. Small intestine, D. Large intestine
A: Cardiac end of stomach
Answer: A: Cardiac end of stomach 
Explanation: Pacemakers (interstitial cells of cajal), are mesenchymal cells with smooth muscle like features. They act as pacemaker of gastrointestinal tract by creating basal electrical rhythm which leads to contraction of the smooth muscles. They are absent in esophagus and proximal poion of the stomach. Ref: Ganong's Review of medical physiology, 22nd Edition, Page 480