3. Complete the sentences:

brain heart blood bones muscles lungs chemicals excretory system eyes ears nose

1. The _______________ is the main center which regulates and coordinates all body activities.

2. The human _______________ normally beats about 70 times a minute making the _______________ move along the arteries, veins and capillaries.

3. _______________ protect and support the organs of the body.

4. _______________ produce all kinds of movements in our body, from smiling and eye blinking to running and weight lifting.

5. _______________are the main organ of breathing.

6. The function of the liver is to metabolize _______________.

7. Kidneys are the part of _______________ _______________, they serve as filters which separate the urine from the blood.

8. Man has several organs of sense: the organs of sight are the _______________, the organs of hearing are the _______________, the organ of smell is the _______________.

Unit 3. Human teeth

Part I. Speaking and vocabulary

Lead – in

Exercise 1: Identify the kinds of teeth and bones shown in the pictures and name them. Describe the functions of these bones.

1__________________	2_______________	3 ____________	4______________
5_________________	6_______________	7____________	jaw canine molar skull wisdom teeth lower jaw (mandible) upper jaw (maxilla)

Exercise 2: Match the name the parts of a tooth with their definitions:

1		The crown	a	are the teeth located at the back of the dental arch. They perform most of the chewing, by crushing and finalizing grinding before swallowing the food.
2		The enamel.	b	are the teeth located next to the incisors towards the edge of the mouth. They have a sharp pointed edge that is used to rip and tear tough foods such as meat. They are the longest and most stable human teeth.
3		The root	c	is the line formed at the point where the crown meets the root. In anatomical terms, it is the point where the enamel meets the cementum, also called the cemento-enamel junction (CEJ).
4		Incisors	d	is the hardest part of the teeth that can be lost with eating excessive acidic food and drinks.
5		Canines	e	is the visible part of the tooth that you can see above the gum line
6		Premolars	f	is the part of the tooth that is under the gum line embedded in the jaw bone, either the maxilla (upper jaw) or mandible (lower jaw). It is the part of tooth that provides support and keeps it in place at the jaw with the help of the periodontal ligaments.
7		Molars	g	are the teeth at the center of the dental arch. The main functions of it in the mastication process are biting, cutting of food into chewable pieces and moving it inwards the mouth.
8		The neck of the tooth (cervical line)	h	are the teeth located after the canines towards the back of the mouth. Their major role is to begin the crushing of foods before they are transferred to the molars for the final grinding.

Exercise 3: Complete the text using the words and phrases:

types of teeth	enamel	dentin
main layers	anatomy	treatments
crown	tissues	cementum
pulp chamber	tooth	canals
blood vessels	fibroblasts	nerves

Although humans have 4 different …. with significant variations in their external morphology, they all share a common internal dental anatomy. All human teeth consist of 3…. The external and hardest of all layers is the…., underneath of enamel there is…., and at the center of the tooth lies the softer and live part of the tooth, the pulp.

A basic knowledge of the internal … of the tooth and its structure is necessary in order to understand the development of several dental conditions, their causes and their… . If we take a section of a human tooth we will be able to distinguish 4 different types of …, enamel, cementum, dentin, and pulp tissue. The main parts of tooth anatomy are Enamel, Dentin, Cementum, and Pulp.

Enamel is the outermost layer of the tooth structure of the …, the part of the tooth that is above the gums. Dental enamel is the hardest and most mineralized substance in the human body.

Dentin is a bone-like material that makes up most of the tooth's structure. It is covered by the enamel in the crown and by the … in the root area of the tooth. It engulfs and protects the living part of the tooth, the pulp tissue.

Cementum is the outer layer of the …. structure for the root part of the tooth which lies under the gum line. It is a bonelike material, almost as hard as enamel, but with a less inorganic composition.

The dental pulp is the soft living tissue of the tooth. It can be found in the …, a cavity in the center of the crown of each tooth, and inside the root …. which connect the pulp cavity with the opening at the root tip (apex) and through that with the rest of the body. The pulp contains …., connective tissue, …, and other cells including odontoblasts, …., macrophages and lymphocytes.