Human Digestive System: Mouth and Tongue Anatomy
Digestive System: The Mouth
Boca: The Gateway to Digestion
The boca, or mouth, is the first chamber of the gastrointestinal tract. It plays a crucial role in mastication (chewing) and salivation (saliva production). The mouth contains the tongue, which aids in digestion and speech (phonation).
The mouth consists of two cavities: the lobby, a horseshoe-shaped space above, separated from the top by arches, and the oral cavity, located behind the lobby.
Oral Cavity Anatomy
- Anterior Wall: Lips and cheeks (lateral)
- Posterior Wall: Isthmus of fauces, a passage connecting the mouth to the pharynx (behind) and the uvula (midline)
- Side Walls: Cheeks
- Upper Wall (Roof): Palate or palatal vault, divided into two parts:
- Hard Palate: Anterior, bony part, formed by the palatine process of the maxilla
- Soft Palate: Posterior, fibrous sheath, containing small muscles, covered by the lining of the mouth
- Floor: Mylohyoid muscle, extending from the hyoid bone
Content of the Mouth
Teeth
Teeth are embedded in the alveolar processes of the jaws. The gums, a dense connective tissue, cover these processes. The dental mucosa lines the tooth sockets, where teeth are implanted (in the alveolodental arcades). Teeth are essential for cutting, tearing, and grinding food.
Each tooth has three distinct parts:
- Corona: Visible portion
- Root: Portion embedded in the jaw
- Neck: Connects the crown to the root
The tooth is composed of dentine or ivory. The crown is covered with enamel, while the root is covered with cement. Cement binds to the alveolar-dental ligament, which consists of fibers that attach the tooth to the alveolus.
The pulp cavity, a hollow space within the crown, extends to the root through one or more channels. These channels carry vessels and nerves to the pulp cavity.
Dental Formula
The dental formula represents the number and shape of teeth in each arch. The formula is the same for the upper and lower arches. In a hemiarcada (half dental arch), starting from the front, we find:
- Two incisors: Serrated cutting edge, single root
- One canine: Blunt shape, single root
- Two premolars (bicuspids): Two cusps, two roots
- Three molars (grindstones): Multiple cusps and roots
The third molar is known as the wisdom tooth. In children, the dental formula includes two incisors, one canine, and two molars, with no premolars.
The Tongue
The tongue is a membranous muscle that fills the mouth when it is closed. It has a free part and a hidden or root. The root attaches to the neighboring bones and the floor of the mouth or mandible.
Tongue Muscles
Muscles that attach the tongue to the jaw, hyoid bone, and styloid process of the temporal bone are called extrinsic muscles of the tongue.
Intrinsic muscles originate and end within the tongue, including longitudinal, transverse, and vertical fibers.
Taste Buds
The tongue is covered with a special mucous coating containing taste buds, which allow us to perceive flavors. The shape of the filiform papillae can be conical or fungiform. The dorsum of the tongue has a V-shaped groove that opens towards the front. The portion behind the V is known as the base.
Lingual Tonsil
The base of the tongue also contains lymphoid tissue called the lingual tonsil (odd and a half).
Salivary Glands
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There are three pairs on each side: parotid salivary gland: is the largest. Is located in front and below the ear and appears to be a superficial gland. Sometimes it gets much within that communicates with the excretory duct faringe.Tiene calledparotid duct that will result in the oral cavity opposite the second molar salivary gland superior.Esta is crisscrossed by an external carotid artery, external jugular vein and nerve that provides innervation to the musculature of the seventh cranial nerve or