Washington Esthetician State Board Practice Exam

Which characteristic of the fifth cranial nerve makes it essential for mastication?

1. It is a sensory nerve

2. It is a motor nerve

3. It is both sensory and motor

4. It controls vision

The correct answer is: It is both sensory and motor

The fifth cranial nerve, also known as the trigeminal nerve, is essential for mastication because it possesses both sensory and motor functions. This dual capability allows it to play a vital role in the process of chewing. The sensory component provides feedback from the teeth, gums, and jaw, allowing the brain to interpret sensations such as pressure and pain during the biting and chewing process. This sensory information is crucial for protecting the teeth and oral structures from damage. Simultaneously, the motor aspect of the trigeminal nerve is responsible for controlling the muscles involved in mastication. This includes the masseter and temporalis muscles, which are fundamental for the movement of the jaw as it opens and closes to grind food. Understanding the dual functionality of the trigeminal nerve highlights why it is critical for effective mastication, as both the sensation of the process and the physical movement are necessary to ensure that food is chewed properly before swallowing.