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PDF Files for PrintingLesson 1-Engage/Explore: What Do Mouths Do?



Exee and his spaceshipLesson 1 engages the students in oral health by introducing a visitor: Exee from planet Y. Exee does not have a mouth and asks students what purpose their mouth serves. After students list everything their mouth helps them do, they sort the functions according to those that help them eat, drink, and communicate. Next, students play the game Mouth Mirrors, in which they mimic the mouth movements of a partner. Through this game, students identify some of the structures of their oral cavity. Next, they eat a cracker and pay attention to how their mouth helps them eat. They connect the structures with the functions of the oral cavity. At the end of the lesson, students begin a Mouth Journal in which they answer the question, What would you tell Exee about the mouth?


In this lesson, students will


After completing this lesson, students will


Our new friend, Exee, the extraterrestrial who zooms in from planet Y, asks a provocative question: Why do people have that hole (the mouth or the oral cavity) in the center of their faces?

the mouthThe mouth is but one of the many sensory organs found in the craniofacial area. This area of our bodies houses the eyes, the ears, the nose, and the tongue—most of our sensory organs other than the skin.

Besides helping us taste food, the mouth performs many functions in basic survival and in other aspects of our lives. Our mouth allows us to take in essential nutrients and water and to communicate, both through speech and facial expressions. All of these functions are essential to life, as we know it.


Eating and Drinking

We must eat food and drink liquids to survive. To ingest food or liquid, our mouth must function correctly. The mouth is designed to take in this food and liquid and begin the digestion process.

drinking juice eating a sandwich

Food must be broken down enough so that we can swallow it without choking or getting the food caught in the throat. How does the mouth do this?

During the ingestion of liquids, the jaw and tongue help pass the liquid to the back of the mouth where we can swallow it.1

Taste and Smell

Did You Know?
Approximately three-fourths of the flavor we experience from food actually comes from the aroma or smell of the food—from our olfactory system. The rest of the flavor we experience depends on taste (whether we sense the food as sweet, sour, bitter, or salty); the texture of the food; and whether we experience irritation, such as spiciness, from the food.2

Did You Know?
Among human expressions, the smile is the most recognized. According to research in this area, only smiles and surprise are identifiable in faces exposed briefly at 150 feet from the observer, and only smiles are identifiable at 300 feet.3

Another function of the mouth is to enable us to savor the food we eat. We enjoy food more when we can distinguish the flavor of the food as well as enjoy its texture. We can taste because we have taste buds that line the surface and sides of the tongue. smelling popcornWe can smell thanks to specialized nervous tissue found at the top of the nasal cavities. We have "common chemical sense" because of the many nerve endings in the linings of the mouth and nose. A number of pathways take the information from these sensory areas to the brain. To fully enjoy the flavor of a food, all three of these senses need to be engaged.

Facial Expressions

Facial expressions can set the mood in many situations and usually tell us what people are thinking or feeling. For example, if we walk toward someone with a smile on our face, we are much more inviting than if we wear an expression of a scowl and pursed lips. Without a mouth and its structures, we would not be able to display our emotions through our expressions.

young girl making a funny face
Photo: Corel

Our lips, teeth, jaws, cheeks, and facial muscles all play an important role in creating facial expressions. We are able to make facial expressions because of the complex muscular structure of the face. We have 22 muscles on either side of the face; humans have more facial muscles than any other animal.

All of our facial muscles are controlled by the facial nerve (cranial nerve VII). This nerve originates in the brain and divides into three branches to control the facial muscles. The first branch of the facial nerve allows our eyes to tear and our mouths to salivate. The second branch sends taste sensations to the brain, and the third directs facial expressions such as smiling, frowning, and squinting.4 In addition, "Human facial skin is mobile and able to shape quickly according to pulses from the brain."4 So, thanks to the nerves and muscles of our face, we can express ourselves very well without using any words at all.


We can form words to speak to one another because of the structure and tissues in our mouth. Our vocal cords and our respiratory system help produce the sounds we call speech. Probably the most important organ in speech formation is a muscle we often take for granted: our tongue. As stated by a speech pathologist,

It could be the most unique muscle in the human body. Much of the time, it just sits still. But, at appropriate moments, the human tongue twists and turns and gyrates, and then, through subtle and exact movements, forms words and says what has to be said. A minute later and with entirely different motions, the muscular tongue can initiate a swallow that will permit its owner to eat and live.5

boy sticking out his tongueHuman tongues, along with their associated nerves, the respiratory system, and the teeth and lips, are much more versatile than those of other animals, allowing humans the ability to speak unlike any other species on Earth.


Activities that include the Web site
Activity Number Web Version
Activity 1 yes
Activity 2 no
Activity 3 no

Activity Number Master Number Number of Copies
Activity 1 Master 1.1, A Visitor from Outer Space 1 copy for each student to color (optional)
1 transparency (optional)
Activity 2 none none
Activity 3 none none
Wrap-up Master 1.2 Mouth Journal
Master 1.3 Mouth Journal Writing Pages
1 copy for each student
6 copies for each student

Activity 1
For the class:
  • Web site address
  • computers with Internet access
  • overhead projector (optional)
  • transparency of Master 1.1, A Visitor from Outer Space (optional)
  • 1 sheet of flip chart paper
  • markers
For each student:
  • 1 copy of Master 1.1, A Visitor from Outer Space (optional)
Activity 2
For the class:
  • list on flip chart paper, What My Mouth Can Do, from Activity 1
  • 1 small mirror
  • 1 sheet of flip chart paper
  • markers
Activity 3
For the class:
  • 1 sheet of flip chart paper
  • markers
For each student:
  • 2 crackers, such as saltines
  • 1 napkin
Wrap-up Activity
For each student:
  • 1 copy of Master 1.2, Mouth Journal
  • 6 copies of Master 1.3, Mouth Journal Writing Pages


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