Look through the last paragraph of the text and find the Infinitives. State their function.

Summary

Hard Palate, Soft Palate and Pharynx

The hard palate forms the roof of the mouth and is covered with keratinized epithelium. Peripherally it is covered with mucoperiosteum continuous with the attached gingival, and attached firmly to the underlying bone. More centrally, in the angle between the palatine and alveolar processes of the maxilla, it is separated from the bone by intervening connective tissue containing blood vessels and nerves. The presence of connective tissue between the epithelium and bone allows anaesthetic to be infiltrated without causing pain. Further centrally and in the midline, the epithelium is again tightly bound down to the underlying bone, which is sometimes raised in the midline as a midline palatal torus of variable size.

In the midline, behind the central incisor teeth lies the incisive papilla, an oval prominence covering the incisal fossa and marking the entry into the mouth of the nasopalatine nerves. Just distal to the incisive papilla there are a variable number of roughly parallel irregular raised folds of mucoperiosteum, the palatal rugae. Further posteriorly, marking the junction of hard and soft palate, lie two small indentations, one on either side of the midline. These are the foveae palatini, where the ducts of two small clusters of salivary glands open into the mouth.

The soft palate is covered with stratified squamous epithelium and divides the oropharynx from the nasopharynx. It terminates distally in a short muscular projection, the uvula. By contact with the posterior wall of the pharynx it regulates the flow of air through the mouth and nose when breathing and speaking.

Laterally the side of the pharynx is marked by two arches. The anterior is produced by the presence of the palatoglossus muscle. It is separated by the pharyngeal tonsil from the distal arch, which is formed by the palatopharyngeus muscle. The pharyngeal tonsil is a collection of lymph tissue and in young patients is frequently red and swollen in response to infection. In later life, it atrophies and even shows calcification. The pharyngeal tonsil is part of a ring of lymphoid tissue, the other parts of which are the lingual tonsil, found on the posterior third of the tongue, and the adenoids, a collection of lymph tissue found in the midline of the posterior wall of the nasopharynx.

Make a summary of the text according to the plan:

A) structures forming the hard palate and attached to it;

B) structure and functions of the soft palate;

C) structures of the pharynx.

Translation

Lips and cheeks

The lips are muscular structures surrounding the opening of the mouth. Externally they are covered with skin which is tightly bound down to the underlying connective tissue and muscle.

The inner surface of the lips is covered with stratified squamous epithelium, tightly attached to the underlying connective tissue and muscle. The epithelium is thin, and through it the underlying blood vessels are visible. The surface is irregular with slight prominences caused by the presence of large numbers of small mixed salivary glands.

The mucous membrane of the cheeks is also tightly bound down to the underlying connective tissue and muscle. To allow for stretching the mucous membrane has a finely wrinkled form in the resting state. In the maxillary second molar region, the mucous membrane of the cheeks is pierced by a duct - the parotid duct - which ends as a papilla of variable size. Further down in the cheek, level with the occlusal surface of the teeth, there is often a lightly raised, horizontal whitish band. This is a band of keratinisation produced by chronic trauma from the teeth. While often barely noticeable, it can be pronounced and lead to confusion with other, pathological, types of white lesion.

Posteriorly and in the line with the corners of the mouth there are often a small number of ectopic sebaceous glands. These are of no significance but can be alarming when present in large numbers. At times a large area may be covered by such sebaceous glands which appear as yellowish spots - Fordyce's spots - and these can cause anxiety when noticed for the first time.

Superiorly and inferiorly, the mucous membrane which is bound down to the underlying muscle loses its attachment and is reflected onto the bone of the alveolar processes. The zone of reflection - the sulcus - must allow for the morbility of the cheeks and the mucous membrane is attached to the underlying structures only by loose connective tissue. The sulci are horseshoe-shaped and are divided into buccal and labial sections related to the cheeks and lips, respectively.

The upper midline fraenal attachment may be enlarged and have a fibrous insertion into the maxilla. Fraena may also be a contributory factor in periodontal disease by interfering with plaque removal. The fraenal attachment may then require surgical removal.

Speaking

1. A student prepared a scheme of the oral cavity but forgot to subscribe the names of the structures. Correct his mistake: give the names of the structures marked by the numbers and describe their position in the oral cavity.

2. Discuss the role and the main purpose of the skull and the oral cavity structures: Eg. ? the skull ? serves as a framework for the head, protects the brain; etc.

Date: 2016-06-12; view: 9