1. Find the adjective in the text and explain how the degrees of comparison are formed.

2. State whether the predicate is used in Passive or Active Voice. Translate the sentences.

1) Cranial and facial bones form the skull. 2) Each rib is composed of a head, neck and body. 3) The main part of the head is called the skull. 4) The skull is composed of twenty six bones. 5) The bones of the skull consist of cranial and facial parts. 6) The bones of the skull are connected with the cervical vertebrae.

3. Find in the text the sentences in the Present Simple Passive and translate them.

Summary

Read the text and make the summary according to the plan:

1. The structures of the skull.

2. The structure and the role of the mandible.

3. The maxilla as a frame for the teeth and cavities.

Skull

A

skull, or cranium, is a bony structure which serves as the general framework for a head. The skull protects the brain, acting as a form of natural helmet.

In humans, the skull is the uppermost portion of the human skeleton. It is made up of a number of bony parts - 8 in the skull proper (neurocranium) and 14 in the facial area (splanchnocranium). There are five main skull sections - one occipital, two frontal, two parietal. The sections are fused together in adults along sutures. At birth these sutures are fibrous and moveable, necessary for birth and later growth. The skull also contains the sinus cavities. The meninges are the membranes that separate the brain from the skull.

The mandible (inferior maxillary bone) is the largest and strongest bone of the face. It forms the lower jaw and holds the lower teeth in place. The mandible consists of a curved, horizontal portion, the body, and two perpendicular portions, the rami, which unite with the ends of the body nearly at right angles. The mandible, which is the bony structure bearing the dental arch, generates masticatory movement and brings the arch to a more effective point for mastication. The size and shape of the dental arch, consisting of teeth, are influenced by tooth size and shape of the mandible. However, the relationship between the morphologies of the teeth and the mandible, is not yet fully understood. As teeth develop in the alveolar bone, which is part of the mandible, their growth partly depends on that of the mandible. Thus, these structures influence each other at the developmental stage.

The maxillae are large bones of the face and form, by their union, the whole of the upper jaw. They hold the upper teeth, and connect on the left and right to the zygomatic bones (cheek bones). Each assists in forming the boundaries of three cavities, namely, the roof of the mouth, the floor and lateral wall of the nose and the floor of the orbit. The maxilla also forms a small part of the orbit of the eye, and extends upwards to the topmost part of the nose. Inside the mouth, the palatine bone lies behind the maxilla on the mouth's roof. Each bone consists of a body and four processes - zygomatic, frontal, alveolar, and palatine.

It is generally accepted that environmental factors have more influence on bony structures because of the attachment of musculature, and that consequently, bone shape is more changeable than tooth form. On the other hand, teeth do not change their shape after the completion of development, so that genetic factors are a better determinant of their shapes.

Translation