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Mouth
Begins preparation of food for digestion
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Pharynx
Transports food from mouth to esophagus
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Esophagus
Transports food from the pharynx to the stomach
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Stomach
Breaks down food & mixes it with digestive juices
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Small Intestine
Completes digestion & absorption of most nutrients
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Large Intestine
Absorbs excess water & prepares solid waste for elimination
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Rectum & Anus
Control excretion of solid waste
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Gallbladder
Stores bile & releases it to the small intestine as needed
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Pancreas
Secretes digestive juices & enzymes into small intestine as needed
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Major organs of the digestive system:
- 1. Oral cavity (mouth)
- 2. Pharynx (throat)
- 3. Esophagus
- 4. Stomach
- 5. Small intestine
- 6. Large Intestine
- 7. Rectum
- 8. Anus
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Accessory organs of digestive system:
- These organs aid digestion but are not part of the digestive system:
- .....1. Liver
- .....2. Gallbladder
- .....3. Pancreas
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Gastrointestinal Tract
- Structures of the digestive system are diveded into:
- .....1. Upper GI tract:
- ..........a. Mouth
- ..........b. Esophagus
- ..........c. Stomach.....2. Lower GI tract:
- ..........a. Small Intestine
- ..........b. Large Intestine
- ..........c. Rectum
- ..........d. Anus
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Bowels
Another name for the small & large intestines
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Oral Cavity
- Major structures include:
- .....1. Lips
- .....2. Tongue
- .....3. Hard palate
- .....4. Soft palate
- .....5. Salivary glands
- .....6. Teeth
- .....7. Periodontium
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Lips
1. Form opening to oral cavity
- 2. During eating, lips:
- .....a. Hold food in the mouth
- .....b. Aid tongue & cheeks in guiding food between teeth for chewing
3. Also have important roles in breathing, speaking, & expression of emotions
4. Also known as labia; singular form: labium. (These terms are also used to describe part of the femle genetalia.)
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Upper & Lower Labial Frenum
Narrow bands of tissue that attatch the lips to the jaws
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Palate
1. Forms the roof of the mouth.
- 2. Consists of the:
- .....a. Hard Palate
- .....b. Soft Palate
- .....c. Uvula
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Hard Palate
1. Bony anterior portion of the palate
2. Covered with specialized mucous membrane that contain rugae.
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Rugae (singular: ruga)
Irregular ridges or folds in the mucous membrane covering the hard palate.
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Soft Palate
1. Flexible posterior portion of the palate.
2. Closes off the nasal passage during swallowing to prevent food & liquid from moving upward into the nasal cavity.
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Uvula
1. Hangs from free edge of the soft palate.
2. During swallowing, moves upward with the soft palate
3. Plays important role in snoring & formation of some speech sounds.
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Tongue
1. Very strong, flexible, & muscular
2. Aids in speech
3. Moves food during chewing & swallowing
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Parts of the Tongue
- 1. Dorsum:
- .....a. Upper surface of tongue
- .....b. Has tough, protective covering
- .....c. Some areas have papillae containing taste buds.
- 2. Sublingual:
- ....a. Under surface of tongue
- .....b. Like tissues under tongue, this surface is covered with delicate highly vascular tissue.
- .....c. This rich blood supply is what allows sublingual medications to be absorbed quickly.
- 3. Lingual frenum:
- .....a. Attaches tongue to floor of mouth
- .....b. Limits motion of tongue
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Papillae
- 1. Small bumps on dorsum (upper surface) of tongue
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- 2. Contain taste buds, the sensory receptors for the sense of taste
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Periodontium
Bone & soft tissue that surround and support teeth
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Gingiva (Gums)
- Specialized mucous membranes that:
- .....1. Surround the teeth
- .....2. Cover the bone of the dental arches
- .....3. Line the cheeks
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Dental arches (upper & lower jaws)
- 1. Bony structures of oral cavity, consisting of:
- .....a. Maxillary arches
- .....b. Mandibular arches
2. Hold teeth firmly in position to facilitate chewing & speaking
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Temporomandibular joint (TMJ)
1. Joint formed at back of mouth where maxillary & mandibular arches come together.
2. The maxillary arch, which is part of the skull, does not move.
3. The mandibular arch, a separate bone, is the moveable component of this joint.
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Dentition
1. Natural teeth arranged in the upper & lower jaws.
- 2. Human dentition includes 4 types of teeth:
- .....a. Cuspids - for biting & tearing:
- ...........(1.) Incisors
- ...........(2.) Canines
- .....b. Bicuspids - for chewing & grinding
- ..........(3.) Premolars
- .....c. (4.) Molars - for chewing & grinding
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Primary dentition (deciduous dentition or baby teeth)
- 1. Consists of 20 teeth that are normally lost during childhood:
- .....a. 8 incisors
- .....b. 4 canines
- .....c. 8 molars
- .....d. NO premolars
2. Replaced by (32) permanent teeth
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Permanent dentition
- 1. Consists of 32 teeth that are designed to last a lifetime:
- .....a. 8 incisors
- .....b. 4 canines
- .....c. 8 premolars
- .....d. 12 molars
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Edentulous
Without teeth - after natural permanent teeth have been lost.
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Malocclusion
Any deviation from the normal positioning of the upper teeth against the lower teeth.
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Occlusion
In dentistry, describes any contact between the chewing surfaces of the upper & lower teeth.
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Structures & Tissues of the Teeth
- 1. Crown:
- .....a. Portion of a tooth that is visible in the mouth
- .....b. Covered with enamel, which is the hardest substance in the body
- 2. Root:
- .....a. Holds tooth securely in place within the dental arch.
- .....b. Roots are protected by the cementum which is strong, but not as hard as enamel.
3. Cervix: Neck of the tooth where the crown & root meet.
- 4. Dentin:
- .....a. Makes up the bulk of the tooth structure
- .....b. Protected on outer surfaces by the enamel & cementum.
- 5. Pulp:
- .....a. Consists of rich supply of blood vessels & nerves
- .....b. Provides nutrients & innervation to tooth
- .....c. In crown, pulp located in pulp cavity
- .....d. In root, pulp continues through the root canal
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Crown of tooth
Portion of tooth visible in mouth
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Enamel of tooth
1. Covers & protects crown of tooth
2. Hardest substance in body
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Root of tooth
1. Holds tooth in place in dental arch
2. Protected by cementum
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Cementum
Hard substance that protects the roots of teeth.
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Cervix of tooth
Neck of tooth where crown & root meet.
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Dentin
- 1. Makes up bulk of tooth structure
- 2. Protected on outer surfaces by enamel & cementum
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Pulp of tooth
1. Consists of a rich supply of blood vessels & nerves
2. Provides nutrients & innervation to teeth
3. In crown - located in pulp cavity
4. In root - located in root canal
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Pulp cavity
Location of pulp in crown of tooth
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Root canal
Location of pulp in root of tooth.
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Saliva
- 1. Colorless liquid that:
- .....a. Moistens the mouth
- .....b. Begins the digestive process
- .....c. Lubricates food during chewing & swallowing
2. Excreted by 3 pairs of salivary glands & carried into mouth via ducts.
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Salivary glands
1. Excrete saliva which is carried into the mouth via ducts.
- 2. There are 3 pairs:
- .....a. Parotid glands
- ..........(1.) Glands located on face in front of & slightly below each ear
- ..........(2.) Ducts are on the inside of the cheek near the upper molars
.....b. Sublingual glands: The glands & their ducts are located on the floor of the mouth under the tongue.
.....c. Submandibular glands: The glands & their ducts are located on the floor of the mouth near the mandible.
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Pharynx (throat)
Common passageway for both respiration & digestion
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Epiglottis
Lid-like structure that closes off entrance to the trachea to prevent food & liquids from moving from the pharynx during swallowing.
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Esophagus
1. Muscular tube through which ingested food passes from the pharynx to the stomach.
2. Backflow of food prevented by lower esophageal sphincter that controls flow between esophagus & stomach.
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Lower Esophageal Sphincter
(cardiac sphincter or gastroesophageal sphincter)
Muscular ring that controls flow of food between the esophagus & stomach.
- 2. Normally:
- ......a. OPENS to allow flow of food into the stomach
- ......b. CLOSES to prevent stomach contents from regurgitating into the esophagus.
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Regurgitation
Means to flow backward.
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Stomach
- Sac-like organ composed of the:
- .....1. Fundus (upper, rounded part)
- .....2. Antrum (lower part)
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Rugae
1. Folds in the mucousal lining of the stomach.
- 2. Glands located within the rugae produce:
- .....a. Gastric juices that aid in digestion
- .....b. Mucus to create a protective coating on the lining of the stomach.
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Pylorus
1. Narrow passageway connecting the stomach & small intestine.
2. Pyloric sphincter is ring-like muscle that controls flows from stomach to small intestine.
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Pyloric sphincter
Ring-like muscle that controls flow from stomach into small intestine.
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