In myasthenia gravis, antibodies are formed against

Options

A. Cholinergic receptors on motor neurons
B. Cholinergic receptors on motor end plate
C. Acetylcholine
D. Adrenergic receptors

Answer

To solve the question regarding what antibodies are formed against in myasthenia gravis, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Myasthenia Gravis**:
- Myasthenia gravis is an autoimmune disorder characterized by weakness and rapid fatigue of the voluntary muscles. This condition occurs when the immune system mistakenly attacks the body's own tissues.

2. **Identify the Role of Antibodies**:
- In myasthenia gravis, the immune system produces antibodies that interfere with communication between nerves and muscles. This is primarily due to the presence of autoantibodies.

3. **Focus on the Neuromuscular Junction**:
- The neuromuscular junction is the site where nerve cells communicate with muscles. Acetylcholine (ACh) is a neurotransmitter that binds to receptors on the muscle cell membrane to trigger muscle contraction.

4. **Determine the Target of Antibodies**:
- Research indicates that in myasthenia gravis, antibodies primarily target acetylcholine receptors (AChR) on the muscle end plate. This leads to a reduced number of functional receptors, impairing muscle contraction.

5. **Analyze the Options**:
- A. Cholinergic receptors on motor neuron: Incorrect, as the antibodies primarily target receptors on the muscle end plate, not the motor neuron.
- B. Cholinergic receptors on motor end plate: This is a potential answer, but it is not the best fit based on the options provided.
- C. Acetylcholine: Incorrect, as antibodies do not target the neurotransmitter itself but rather the receptors that respond to it.
- D. Adrenergic receptors: Incorrect, as these are not involved in myasthenia gravis.

6. **Select the Correct Answer**:
- Based on the information and the roles of the components involved, the correct answer is **B. Cholinergic receptors on motor end plate**, as these are the receptors that the antibodies attack.

### Final Answer:
**B. Cholinergic receptors on motor end plate**