Digestive 1 Flashcards
Oral cavity: Boundaries
Superior border (roof of oral cavity):
Hard Palate
Soft Palate
Posterior border: oropharyngeal isthmus (aka fauces)
Inferior border (floor of oral cavity): Tongue
Anterior border: Lips
Lateral borders: Cheeks
Palatoglossal arch
Anchor soft palate to tongue
Palatopharyngeal arch
Anchor soft palate to wall of oropharynx
Hard palate
rigid surface where the tongue forces food during chewing. Made by palatine processes of maxillae and horizontal plates of palatine bones.
Soft palate
a soft, mobile flap - rises to close nasopharynx during swallowing
Terminal sulcus
•marks the border between mouth and
pharynx
•Posterior 1/3 – lingual tonsil
•Anterior 2/3 - covered with papillae
Circumvallate papillae
- Border terminal sulcus
* House >100 taste buds on sides
Foliate papillae
- Ridges on sides of the tongue
* House >100 taste buds
Fungiform papillae
- Mushroom shaped and red in colour
* Contain 3-5 taste buds on top
Filiform papillae
- Thread-shaped, roughen tongue
- Small and numerous.
- Do not contain taste buds
Hypoglossal nerve (CN XII)
Innervates most intrinsic and
extrinsic muscles of the tongue
Intrinsic muscles (Tongue)
Confined within the tongue and not attached to bone.
Change shape of tongue
Extrinsic muscles (Tongue)
- Attach tongue to bones.
- Alter position of tongue
- 4 pairs:
- Styloglossus
- Genioglossus
- Hyoglossus
- Palatoglossus
Facial nerve (CN VII)
For taste
Trigeminal nerve (CN VII)
(Lingual nerve) for sensation
Glossopharyngeal nerve (CN IX)
Sensation and taste for
posterior 1/3 of tongue
(contains lingual tonsil)
Salivary Glands
- Parotid gland (Par = near, otid = the ear)
- Submandibular gland
- Sublingual gland
- Parotid gland (Par = near, otid = the ear)
- Situated in front of ear superficial to ramus of mandible
* Parotid duct drains into vestibule of mouth opposite upper second molar
- Submandibular gland
- Located beneath mandible
* Submandibular ducts release saliva onto floor of mouth from either side of the frenulum
- Sublingual gland
- Beneath tongue
* Releases saliva from several small openings just underneath the tongue
Gleeking
is achieved by compression of the submandibular ducts
by muscles in the floor of the mouth when you move your tongue upwards.
Sialography:
radiographic examination of the salivary glands. Evaluates the functional integrity of the salivary glands in case of obstructions or other pathologies.
Saliva
- Water and mucus
- Ions
- Enzymes: amylase and lipase
- Bactericidal enzymes and antiviral substances
- Can transmit infection
Mumps
A virus that spreads from one person to another through saliva
Causes inflammation and swelling of the parotid glands
Pharynx
A muscular tube which runs from the internal nares to the esophagus and
carries food and air to the respiratory and digestive structures
Pharynx 3 portions
Nasopharynx
Oropharynx
Laryngopharynx
Tonsils:
- 4 sets
- Accumulation of lymphoid nodules
- First line of defense against organisms entering oral or nasal cavities
Palatine Tonsils
Most often removed - tonsillectomy
Lingual Tonsils:
• Base of tongue
Tubal Tonsils:
• Located around Eustachian tube
Pharyngeal Tonsils:
• Also known as “adenoids”
Swallowing: 1. Oral phase
- Mouth→Oropharynx
- Food bolus formed
- Chewing, masticating
Swallowing: 2. Pharyngeal stage
- Oropharynx → Esophagus
* Nasal cavity and larynx closed off
Swallowing: 3. Esophageal stage
- Esophagus→Stomach
* Completes swallowing process
Oral phase detailed
- Voluntary
- Action: tongue elevates and pushes food bolus against the hard palate and backwards into the oropharynx
- Intrinsic and extrinsic muscles of the tongue and buccinators push the food bolus back until it reaches the palatoglossal and palatopharyngeal arches
Pharyngeal phase detailed
• Involuntary (gag reflex)
• Action: Blockage of 3 cavities and
contraction of pharynx forces bolus into
esophagus
Pharyngeal phase blocked cavities
- Blockage of 3 cavities:
I. Oral Cavity by elevation of the tongue
II. Nasal cavity by elevation of soft palate
III. Larynx by elevation of the larynx which causes epiglottis to fold over the laryngeal inlet
suprahyoid muscles
lift the larynx superiorly and anteriorly Mylohyoid Stylohyoid Digastric Hyoid bone
Elevation/contraction of soft palate
Tensor veli palatini: tenses soft palate
Levator veli palatine: elevates soft palate
Palatopharyngeus: pulls soft palate down after it has been elevated
Pharyngeal constrictor muscles
Superior pharyngeal constrictor
Middle pharyngeal constrictor
Inferior pharyngeal constrictor
- Encircle pharynx and partially overlap each other
- Contract sequentially during swallowing starting with the superior constrictor
Esophageal phase detailed
• Involuntary
• Action: downward movement of bolus through esophagus and into stomach
1. Contraction of skeletal muscle in the upper part of the esophagus
2. Peristalsis: wave-like contraction of smooth muscle in the lower part of the esophagus
Peristalsis
involuntary process that involves alternate waves of
contraction and relaxation of muscles in the organ (in this case, esophagus) walls. The net effect is to squeeze food along a pathway – in this case down the
esophagus.
infrahyoid muscles
pull the hyoid bone and larynx inferiorly returning them to their original position
Sternohyoid
Omohyoid
Thyrohyoid - Superior continuation of sternothyroid
Sternothyroid - Deep to sternohyoid
