Tetanus is caused by a toxin that acts on the nervous system.

Tetanus is caused by a toxin that acts on the nervous system.

• A. False
• B. True
• C. Not sure
• D. Both

Answer: (B)

The main idea tested is that tetanus is caused by a toxin that targets the nervous system. The toxin known as tetanospasmin is produced by Clostridium tetani and travels into the central nervous system where it blocks the release of inhibitory neurotransmitters like GABA and glycine. This disinhibits motor neurons, leading to the painful, characteristic muscle rigidity and spasms of tetanus. The critical point is that the disease symptoms come from the toxin’s effect on neural signaling, not from the bacteria injuring muscles directly. So stating that tetanus is caused by a toxin that acts on the nervous system is correct.

The main idea tested is that tetanus is caused by a toxin that targets the nervous system. The toxin known as tetanospasmin is produced by Clostridium tetani and travels into the central nervous system where it blocks the release of inhibitory neurotransmitters like GABA and glycine. This disinhibits motor neurons, leading to the painful, characteristic muscle rigidity and spasms of tetanus. The critical point is that the disease symptoms come from the toxin’s effect on neural signaling, not from the bacteria injuring muscles directly. So stating that tetanus is caused by a toxin that acts on the nervous system is correct.