Lecture 1 - Digestive System
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Lecture 1 - Digestive System
What are the four main functions of the digestive system?
Ingestion; digestion; absorption and defecation
What is ingestion?
Taking in of food
What is digestion?
chemical and mechanically breakdown food
What is absorption?
passage of food from the GI tract into the cardiovascular system
What is defecation?
elimination of the wastes
How long is the alimentary canal or GI tract?
approximately 30 feet long from mouth to anus
What is the general organization of the digestive tract?
Mouth--Pharynx--Esophagus--Stomach--Small and Large Intestines
What are the accessory glands of the digestive system?
Salivary glands; liver; gallbladder; and pancreas
What are the different parts of the mouth?
Hard palate; soft palate; teeth and tongue
Where is the hard palate?
Roof of oral cavity and anterior to the soft palantine
What is the hard palate made of?
Made of palantine and maxilla bones and lined with mucus membrane
Where is the soft palate?
Posterior to the hard palate
What does the soft palate consist of?
Contains the uvula, which closes off the nasopharynx when swallowing
What is the purpose of the teeth to the digestive system?
To chew or masticate; composed of Dentin and covered by enamel
What are the two kinds of teeth?
Deciduous (milk) and Permanent
How many dediduous teeth are there?
Describe the deciduous (milk) teeth
there are 20; no premolars; there are 10 in the aveolar process of the maxilla and mandible; in the half jaw there are 2 incisors; 1 cuspid or canine and 2 molars
What is the dental formula for the deciduous teeth?
2-1-2 over 2-1-2
How many teeth do adults have for their permanent teeth?
Describe permanent teeth
there are 32; 16 in aveolar process of maxilla and mandible; in the half jaw there are 2 incisors; 1 cuspid or canine; 2 premolars or bicuspids; 3 molars or tricuspids; wisdom tooth
What is the dental formula for permanent teeth
2-1-2-3 over 2-1-2-3
What is the job of the incisor?
cutting or biting food
What is the job of the canines?
What is the job of the premolars and molars?
crushing and grinding food
What are the different parts of the tongue?
The main part (skeletal muscle); lingual frenulum; and papillae
The skeletal muscle of the tongue is covered with?
a mucus membrane
What is the lingual frenulum?
it attaches the tongue to the floor of the oral cavity
What is the papillae?
projections covered with epithelium on the tongue, some contain taste buds
What are the three types of papillae?
fungiform; filiform and circumvallate
What is fungiform?
mushroom like elevations among the filiform and tip; appears as red dots; most contain taste buds
What is the filiform?
most numerous; conical projections on the anterior; 2/3; parrellel rows; contain NO taste buds
What is the circumvallate?
Arranged in the form of an inverted "V"; on the posterior and all contain taste buds
Which papillae portion does not contain taste buds?
Which part of the papillae tastes sweet food?
What part of the papillae is the circumvallate found?
the posterior part of the tongue
Where is the filiform found?
In the center of the tongue
Where is the fungiform found?
the tip of the tongue