This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
[{'content': 'The latent period of muscle twitch is 10ms and the contraction period is 40ms. What is the tetanizing frequency (Hz)? \nSelect and explain. \nA. 25, B. 50, C. 100, D. 75', 'role': 'user'}, {'content': "Answer: A \nExplanation: Tetanizing frequency = 1/Contraction period = 1/40ms = 25Hz Tetanizing Frequency As the contractile mechanism does not have a refractory period, on rapid stimulation of a muscle, each new contraction occurs before the preceeding one is over. As a result, the second contraction is added paially to the first, and thus the total strength of contraction rises progressively with increasing frequency . Such a response is called a tetanus (tetanic contraction). It is a complete tetanus when no relaxation occurs between stimuli. Tetany occurs because enough calcium ions are maintained in the muscle sarcoplasm throughout the period of stimulation. Ref: Ganong's Review of Medical Physiology 26th edition Pgno: 107", 'role': 'assistant'}]