Tetanus affects primarily
**Core Concept**
Tetanus is a neurological disorder caused by the toxin produced by **Clostridium tetani**, affecting the nervous system. The primary impact is on the **motor neurons**, leading to muscle stiffness and spasms. This condition highlights the importance of **neuromuscular transmission**.
**Why the Correct Answer is Right**
The correct answer is related to the neurological effects of tetanus toxin, which blocks the release of **inhibitory neurotransmitters** like **glycine** and **GABA**, resulting in unchecked muscle contraction. This leads to the characteristic symptoms of tetanus, including **muscle rigidity** and **spasms**. The toxin's effect on the **central nervous system** is crucial for understanding its clinical presentation.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because tetanus primarily affects the nervous system, not the cardiovascular system.
**Option B:** This option is wrong as tetanus toxin does not directly target the gastrointestinal system.
**Option D:** This choice is incorrect because, although tetanus can lead to systemic effects, its primary impact is not on the renal system.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that tetanus toxin's effect on **inhibitory neurotransmitter release** is the basis for its clinical manifestations, making **muscle spasms** and **rigidity** hallmark symptoms.
**Correct Answer:** D. motor neurons, primarily those inhibitory neurons that regulate muscle tone.