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Section - D up meat Graphic Organiser
13. Complete the following table.
c
Type of
teeth
How they
help
ection - E
Long Answer Questions
swer the following question(s) in four to five sentences:
Answers
Answer:
Teeth Important?
Every time we smile, frown, talk, or eat, we use our mouths and teeth. Our mouths and teeth let us make different facial expressions, form words, eat, drink, and begin the process of digestion.
The mouth is essential for speech. With the lips and tongue, teeth help form words by controlling airflow out of the mouth. The tongue strikes the teeth or the roof of the mouth as some sounds are made.
When we eat, our teeth tear, cut, and grind food in preparation for swallowing. The tongue helps push food to the teeth, and allows us to taste the food we eat.
What Do the Parts of the Mouth Do?
The mouth is lined with moist mucous (MYOO-kus) membranes. The membrane-covered roof of the mouth is called the palate (PAL-it):
The front part consists of a bony portion called the hard palate. The hard palate divides the mouth and the nasal cavity above.
The fleshy rear part is called the soft palate. The soft palate forms a curtain between the mouth and the throat, or pharynx, to the rear. When we swallow, the soft palate closes off the nasal passages from the throat to prevent food from entering the nose.
The soft palate contains the uvula (YOO-vyoo-luh), the dangling flesh at the back of the mouth. The tonsils are on either side of the uvula and look like twin pillars holding up the opening to the throat, or pharynx (FAR-inks).
A bundle of muscles extends from the floor of the mouth to form the tongue. The top of the tongue is covered with tiny bumps called papillae (puh-PIL-ee). These contain tiny pores that are our taste buds. Four main kinds of taste buds are found on the tongue — they sense sweet, salty, sour, and bitter tastes.
During chewing, salivary glands in the walls and floor of the mouth secrete saliva (spit), which moistens the food and helps break it down even more. Saliva makes it easier to chew and swallow foods (especially dry foods), and contains enzymes that help begin the digestion of foods.
Once food is a soft, moist mass, it's pushed to the back of the mouth and the throat to be swallowed.
How Do Teeth Do Their Job?
Each type of tooth plays a role in the chewing process:
Incisors are the squarish, sharp-edged teeth in the front of the mouth that cut foods when we bite into them. There are four on the bottom and four on the top.
On either side of the incisors are the sharp canines. The upper canines are sometimes called eyeteeth or cuspids.
Behind the canines are the premolars, or bicuspids, which grind and mash foods. There are two sets, or four premolars, in each jaw.
The molars, found behind the premolars, have points and grooves, and allow for vigorous chewing. There are 12 molars — three sets in each jaw called the first, second, and third molars. The third molars are the wisdom teeth. Because they can crowd out the other teeth or cause problems like pain or infection, a dentist might need to remove them.
Humans are diphyodont (dy-FY-uh-dant), meaning that they develop two sets of teeth. The first set are 20 deciduous (duh-SID-you-wus) teeth that are also called the milk, primary, temporary, or baby teeth. They begin to develop before birth and begin to fall out when a child is around 6 years old. They're replaced by a set of 32 permanent teeth, which are also called secondary or adult teeth.
What Are the Parts of the Teeth?
Human teeth are made up of four different types of tissue: pulp, dentin, enamel, and cementum.
The pulp is the innermost portion of the tooth and consists of connective tissue , nerves, and blood vessels, which nourish the tooth. The pulp has two parts — the pulp chamber, which lies in the crown, and the root canal, which is in the root of the tooth. Blood vessels and nerves enter the root through a small hole in its tip and extend through the canal into the pulp chamber.
Answer:
Chromatography is a laboratory technique for the separation of a mixture. The mixture is dissolved in a fluid called the mobile phase, which carries it through a system on which is fixed a material called the stationary phase.