Palate

The palate forms the roof of the oral cavity and consists of a hard anterior part and a soft posterior part. The hard palate is formed by the palatine processes of the maxillary bones in front and the horizontal portions of the palatine bones in back. The soft palate forms a muscular arch, which extends posteriorly and downward as a cone-shaped projection called the uvula.

During swallowing, muscles draw the soft palate and the uvula upward. This action closes the opening between the nasal cavity and the pharynx, preventing food from entering the nasal cavity.

In the back of the mouth, on either side of the tongue and closely associated with the palate, are masses of lymphatic tissue called palatine tonsils. These structures lie beneath the epithelial lining of the mouth and, like other lymphatic tissues, help protect the body against infections (see chapter 16, p. 656).

Hard palate

Soft palate -

Uvula-

Palatine tonsils —

Small White Macule Palatopharengeal Fold

The mouth is adapted for ingesting food and preparing it for digestion.

Root

Body

Epiglottis

Body

Human Anatomy Tongue

Papillae

Figure 17.6

The surface of the tongue, superior view.

Epiglottis

Lingual tonsils

Palatine tonsil

Papillae

The palatine tonsils are common sites of infection, and when inflamed, produce tonsillitis. Infected tonsils may swell so greatly that they block the passageways of the pharynx and interfere with breathing and swallowing. Because the mucous membranes of the pharynx, auditory tubes, and middle ears are continuous, such an infection can spread from the throat into the middle ears (otitis media).

When tonsillitis occurs repeatedly and does not respond to antibiotic treatment, the tonsils are sometimes surgically removed. Such tonsillectomies are done less often today than they were a generation ago because the tonsils' role in immunity is now recognized.

Figure 17.6

The surface of the tongue, superior view.

Frontal sinus

Nasal cavity

Hard palate Vestibule

Tongue Tooth Lip

Frontal sinus

Nasal cavity

Hard palate Vestibule

Lingual Tonsil Saggital View

Sphenoidal sinus

Oropharynx Lingual tonsils

Epiglottis

Laryngopharynx

Esophagus

Trachea

Hyoid bone

Figure 17.7

A sagittal section of the mouth, nasal cavity, and pharynx.

Other masses of lymphatic tissue, called pharyngeal tonsils, or adenoids, are on the posterior wall of the pharynx, above the border of the soft palate. If the adenoids enlarge and block the passage between the pharynx and the nasal cavity, they also may be surgically removed (fig. 17.7).

Sphenoidal sinus

Pharyngeal tonsils

Opening of auditory tube

Soft palate

Nasopharynx

Oral cavity

Uvula

Palatine tonsils

Hyoid bone

Oropharynx Lingual tonsils

Epiglottis

Laryngopharynx

Esophagus

Trachea

Figure 17.7

A sagittal section of the mouth, nasal cavity, and pharynx.

U What are the functions of the mouth?

^9 How does the tongue function as part of the digestive system?

^9 What is the role of the soft palate in swallowing? Q Where are the tonsils located?

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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