This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Physiology
Positive feedback is seen in all except 
Select and explain. 
A. LH surge, B. Entry of calcium into sarcoplasmic reticulum, C. Gastric secretion, D. Thrombus formation
C: Gastric secretion
Answer: C: Gastric secretion 
Explanation: Ans. (c) Gastric secretion(Ref: Guyton, 13th ed/p.7)Gastric secretion is an example for a negative feedbackIncrease in levels of gastric acid inhibits its own productionPositive feedback - once started, it enhances or amplifies the effect on its own. That is why positive feedback is also called VICIOUS CYCLEExamples of positive feedback are, (CLASP)#Clotting#LH surge#Action potential#Shock#Parturition