口腔

The oral cavity comprises the lips, cheeks, palate, and tongue. The walls are lined with thick, stratified squamous epithelium, while the gums, hard palate, and dorsum of the tongue have mildly keratinized epithelium. The oral cavity is divided into the oral vestibule, a space between the lips or cheeks and the gums, and the oral cavity proper, which continues toward the fauces.

The hard palate, formed by the maxillae and palatine bones, is covered by mucous membrane and contributes to chewing. The soft palate is a flexible fold composed mainly of skeletal muscle that closes off the nasal passages during swallowing to prevent food from entering the nose. The uvula, a finger-shaped structure, hangs from the soft palate's free edge.

The lips and cheeks are muscular structures made up of the orbicularis oris and buccinators, respectively. They keep food inside the mouth during chewing and are vital for speech and facial expressions. The labial frenulum, a fold connecting the inside of each lip to the gum, helps stabilize these structures.

Saliva, produced by three pairs of salivary glands—the parotid, submandibular, and sublingual glands—moistens food, making it easier to chew and swallow. Saliva also contains enzymes that initiate breaking down food, especially carbohydrates, before it reaches the stomach, beginning the process of mechanical and chemical digestion.

The tongue is a muscular organ that allows us to taste food through its taste buds, assists in forming speech sounds, and helps in swallowing. It works with the palate and other oral structures to manipulate food during mastication and facilitate its movement toward the pharynx.

The walls of the oral cavity are lined with thick, stratified squamous epithelium, which provides protection against mechanical stress and abrasion. The gums, hard palate, and dorsum of the tongue have mildly keratinized epithelium, which offers additional durability in areas subject to greater wear during chewing and swallowing.

Poor oral hygiene can lead to tooth decay (cavities), gum disease (gingivitis and periodontitis), oral infections, and bad breath (halitosis). Regular brushing, flossing, and dental check-ups, combined with a healthy diet low in sugar and high in fruits, vegetables, and dairy products, help prevent these problems.