Lesson 1 in science Human digestive track.

Mouth

• Entrance to the digestive system

• Teeth and tongue that digest food mechanically digest food

• Salivary glands secretions initiate chemical digestion

• Mammals generally have anatomically similar mouths

Teeth

• Adults have 32 teeth children have 20 or fewer depending on their age.

• The incisors and canines are use for cutting and tearing

• Premolars are for chewing and grinding food

• Food is broken down mixed with saliva to make chemical digestion

The crown located above the gums the neck is in between the crown and root. The root holds the teeth in place.

Pulp cavity contains blood vessels located at the center of the tooth when its inflamed it causes a tooth ache

Parts of the Pulp cavity:

• Dentin is the hard bony substance surrounding the pulp cavity

• Enamel layer of calcium phosphate covers the dentin enables teeth to chew hard food

Tongues and salivary glands

• Rough surface because of the papillae

• Three types of papillae vallate foliate and fungiform

• The taste buds are cluster of taste receptors cell that makes the 5 taste: bitter salty sour sweet and umami.

• the human tongue has about 2000 to 5000 taste buds

• Saliva is secreted by the salivary glands

• saliva moistens food

• The saliva is responsible in maintaining the Ph level in the mouth at 6.2 and 7.6

Saliva contains a enzyme called salivary amylase helps in digestion of starch a complex carbohydrate by breaking it down into maltose a simple carbohydrate

pairs of the salivary glands

• The parotid

• sublingual

• submandibular glands

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