This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
Tetanus affects primarily 
Select and explain. 
A. Presynaptic terminal of spinal cord, B. Postsynaptic terminal of spinal cord, C. Neuromuscular junction, D. Muscle fibres
A: Presynaptic terminal of spinal cord
Answer: A: Presynaptic terminal of spinal cord 
Explanation: The manifestation of tetanus is due to tetanospasmin. The tetanus toxin specifically blocks synaptic inhibition in the spinal cord, presumably at inhibitory terminals that use glycine and GABA. The toxin acts presynaptically. The abolition of spinal inhibition causes the uncontrolled spread of impulses initiated anywhere in the central nervous system. This results in muscle rigidity and spasms due to the simultaneous contraction of agonist and antagonists in the absence of reciprocal inhibition. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 265