During swallowing of food which of the following structures prevent the entering of food into the glottis ?

Options

A. Semilunar Valve
B. Circular Muscular flap
C. Cartilaginous flap
D. Circular sphincter

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which structure prevents food from entering the glottis during swallowing. The glottis is part of the larynx where the vocal cords are located.

2. **Identifying Relevant Structures**: The options given are:
- Semilunar valve
- Circular muscular flap
- Cartilaginous flap
- Circular sphincter

3. **Defining the Glottis**: The glottis is the opening between the vocal cords in the larynx. It is essential to protect this area during swallowing to prevent food from entering the airway.

4. **Recognizing the Role of the Epiglottis**: The epiglottis is a structure that is closely associated with the glottis. It is a flap made of cartilage that covers the trachea (windpipe) during swallowing.

5. **Function of the Epiglottis**: When food is swallowed, the epiglottis folds down to cover the glottis, preventing food from entering the trachea and directing it into the esophagus (food pipe).

6. **Conclusion**: Since the epiglottis is a cartilaginous flap that serves this protective function, the correct answer to the question is **option C: cartilaginous flap**.