Lecture 17: GI 1.5 Flashcards
What is the tissue at the beginning and ending of the GI tube?
Stratified Squamous Epithelium
What is the function of the Stratified squamous epithelium at the beginning and end of the tube?
Protects from abrasion
What is the Oral Mucosa?
The stratified squamous epithelium in the oral cavity
Which structures help with digestion in the Oral cavity?
Teeth, Tongue, Palatal surfaces, Cheeks
What is the function of Saliva?
- Lubricate food
* Mix food with serous fluid and chemicals to break down food
What is Amylase?
An enzyme that breaks down carbs
What does the Hard Palate do?
Separates the nasal and oral cavity
What does the soft palate do?
Allows you to chew and breathe at the same time
What are the cheeks made of?
Buccal fat pads + oral mucosa
What is the Oral Vestibule?
The space between the lips, cheeks and teeth
Which part mixes air, food and liquid?
The Pharynx
What are the three parts of the Pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What are the 3 tonsils called?
Pharyngeal, Palatine, Lingual
What are the 3 main parts of teeth?
- Crown
- Neck
- Root
What is a Gomphosis?
The joint between a tooth and a bone held by the periodontal ligament
What is the Root Canal?
The portion of teeth that contain vessels to feed teeth
Where does the Root Canal end up?
The pulp cavity
Where does the Root Canal end up?
The pulp cavity
What are the four shapes of teeth?
- Incisors
- Canines
- Premolars
- Molars
What is the function of Incisors?
Blade-like, clip/cut food
What is the function of Canines?
Pointed, tear/slash food
What is the function of Premolars (bicuspid)?
Crush/mash/grind food
What is the function of the Molars (Multi-cuspid)?
Crush/grind food
Which teeth are Bicuspid?
Premolars
Which teeth are multi cuspid?
Molars
What is the upper dentition innervated by?
CN V2 (maxillary branch)
What is lower detention innervated by?
CN V3 (mandibular branch)
How many permanent teeth are there?
32
When do permanent teeth erupt?
Between 6-18
How many incisors are there?
4 - the central and lateral ones
How many canines are there?
2
How many premolars are there?
Four
How many Molars are there?
Three
How many baby teeth/deciduous teeth are there?
20
What do baby teeth lack?
Premolars
Which CN innervates the tongue?
CN XII - Hypoglossal
What are the two types of Tongue Muscles?
- Intrinsic
* Extrinsic
How many orientations do Intrinsic muscles have?
3
How many orientations to Extrinsic muscles have?
5
What do Intrinsic muscles control?
Shape of the tongue for speech
What do Extrinsic muscles control?
Swallowing
What are the Extrinsic muscles of the tongue?
- Palatoglossus
- Styloglossus
- Hyoglossus
- Genioglossus
What tissue is the surface of the tongue made of?
Stratified epithelium
What does the Terminal Sulcus of the tongue do?
Separate the anterior (body) of the tongue and the posterior 1/3 (root) of the tongue
What is sensation of the Anterior 2/3 of the tongue done by?
The mandibular nerve - CN V3
What is the sensation of the posterior 1/3 of the tongue innervated by?
Glossopharyngeal - CN IX
Which part of the tongue have different receptors of tase?
The papillae
What is taste of the Tongue innervated by?
Anterior 2/3 - Facial N via chorda tympani CN VII
Posterior 1/3 - Glossopharyngeal CN IX
What do the exocrine glands with ducts into the oral cavity secrete?
- Serous secretions
* Mucous secretions
What do serous secretions in the oral cavity do?
Moisten food and contain enzymes (amylase) to break down carbohydrate
What do Mucous secretions in the oral cavity do?
Lubricate the passage of food
What enzyme does the saliva contain?
Amylase
What are the functions of Saliva?
- Contain amylase
- Buffers to regulate oral pH
- Contain antibodies for immune surveillance
- Dissolves chemicals that stimulate the taste buds
What are the glands in the Oral Cavity?
- Sublingual gland
- Submandibular gland
- Parotid gland
What is the largest salivary gland in the oral cavity?
Parotid gland
Where does the Parotid gland duct empty?
In oral vestibule by 2nd maxillary molar
What is the Parotid gland innervated by?
CN IX (glossopharyngeal nerve)
What does the Parotid gland secrete?
Serous secretions (amylase)
What does the Sublingual gland of the oral cavity secrete?
Mainly mucous secretions (mucin)
Where are sublingual ducts in the mouth?
The floor of the mouth - sublingual plicae
What is the Sublingual gland innervated by?
Parasympathetic innervation - CN VII (facial nerve)
What is the Sublingual Plica associated with?
The sublingual gland
What does the Submandibular gland secrete?
A mixture of serous and mucous secretions
What is the submandibular gland innervated by?
Parasympathetic innervation - CN VII (facial nerve)
What is the Sublingual Caruncle associated with?
The submandibular glands
Why does the pharynx not have respiratory epithelium?
Because it is a common passageway for for food, liquid and air
What type of epithelium is the pharynx made of?
Stratified squamous epithelium
Which muscles elevate the palate when swallowing?
Tensor and levator palatini
What are the names of the Pharyngeal Constrictors?
Superior, middle and inferior
What do the Pharyngeal constrictor muscles do?
Help elevate the larynx and push the bolus towards the esophagus
What do glands in the Pharynx secrete?
Serous and mucous substances
What is the Pharynx innervated by?
CN X - Vagus nerve
What muscles contract when swallowing?
- Tongue muscles
- Muscles on the floor of the mouth
- Levator and tensor veli palatini muscles
- Pharyngeal constrictors
What ensures the nasopharynx is closed when swallowing?
Elevation of the pharynx and larynx
What do circular muscles of the esophagus do?
ensures food doesn’t go backwards
What do longitudinal muscles of the Esophagus do?
Propel food forward
What is segmentation?
Contracting both the longitudinal and circular muscles in the stomach and colon which doesn’t cause movement but breaks down food or compacts food
Where does the Esophagus span?
C6 - T7 cricoid cartilage to posterior mediastinum to abdomen
What is the transition of muscle in the esophagus?
It goes from skeletal to smooth muscle
What does the cardiac spinchter of the esophagus do?
Pinches off the esophagus from the stomach to ensure there is no acid going up