Final answer:
The muscles responsible for facial expression insert into the skin and facilitate movement of facial features to convey emotions. The parotid salivary gland, located posterior to the mandible and deep within the parotid fossa, is key in saliva secretion, aiding digestion and maintaining oral health.
Step-by-step explanation:
Muscles Involved in Facial Expression
The muscles involved in facial expression are unique because they insert into the skin, allowing for a wide range of expressive movements by altering the skin's position rather than moving bones. These muscles include the orbicularis oris, zygomaticus major and minor, orbicularis oculi, frontalis, and many others that surround the eyelids, nose, and mouth. The facial muscles are an essential part of our non-verbal communication and allow us to display emotions such as happiness, sadness, anger, and surprise.
Location of the Parotid Salivary Gland
The parotid salivary gland is the largest of the three major pairs of salivary glands. It lies posterior and deep to the ramus of the mandible within the parotid fossa. The parotid gland is situated between the skin and the masseter muscle, near the ears, and its duct opens near the second upper molar tooth, releasing saliva into the mouth which is essential for the initial stages of digestion and oral hygiene.