What are the sections of the oral cavity?
The oral cavity proper.
The oral vestibule (the section between lips and teeth)
What are the boundaries of the oral cavity?
Stretches from the lips back to the glossopalantine arch (the first arch and where the uvula hang from)
And from the palate to the floor of the mouth
Explain the passage of the parotid duct?
It pierces the buccinator muscle then opens into the oral cavity on the inner cheek opposite the maxillary 2nd molar.
Explain the passage of the submandibular duct?
Lies superior to the digastric muscle.
Explain the structure of the submandibular gland?
Each one is divided into superficial and deep lobes separated by the mylohyoid muscle.
The superficial is the lobe below the mylohyoid, on the external surface
Which embryological structures form the tongue?
The ant 2/3rds from from the 1st branchial arch
The post 3rd forms from the 3rd branchial arch
Explain the innervation of the tongue:
The ant. 2/3rds are innervated by the lingual nerve which contains fibres from the:
- Mandibular division of the Trigeminal nerve carrying general somatic afferent innervation from the tongue
- Chorda Tympani branch of the facial nerve providing special (taste) sensation.
Post. 1/3rd is supplied by the Glossopharyngeal nerve (Cr N IX)
Describe the papillae of the tongue?
Comes in 4 types:
Filiform - very numerous but no taste buds
Fungiform - scattered on tongue dorsal surface
Folliate - Fairly Rudimentary
Circumvallate - In a row just anterior to the sulcus terminalis
What is the sulcus terminalis?
A V shaped groove that demarcates the junction of oral and pharyngeal portions of the tongue base.
What are the muscles of mastication?
Lateral & Medial Pterygoid
What innervates the muscles of mastication and what do they do?
They act on the temporomandibular joint. Hinge it to open and close jaw and slide it to grind teeth from side to side.
Innervated by The mandibular division of the trigeminal nerve (V3 Cr N V)
Explain the muscle of the tongue
Split into intrinsic/extrinsic which alter the tongue shape & position respectively.
The extrinsic all end in -glossus
All the muscles of the tongue are innervated by the hypoglossal nerve (CN XII) except for the palatoglossal which is supplied by the pharyngeal plexus (CN 9/10)
What are the boundaries of the oropharynx?
Extends from the lower border of the soft palate to the upper border of the glottis.
Superiorly from the palatoglossal arch back to the posterior pharyngeal wall
Laterally it encloses the two arches (palatoglossal and palatopharyngeal) and the palatine tonsils in between.
What are the boundaries of the hypopharynx?
Extends from the sup border of the glottis to the lower border of the cricoid cartilage.
Its anterior wall is the posterior wall of the larynx
How do we divide up the hypopharynx?
Post Cricoid Area
What arteries and nerves supply the hypopharynx?
Sup. Thyroid Art
Asc. Pharyngeal Art
Pharyngeal plexus (CN IX/X)
What are the phases of swallowing?
- Voluntary propulsion of the bolus to the pharynx triggering the swallowing reflex
- Glottis covers the larynx
- Soft palate pulls up to cover nasal cavity
- Larynx pulls up
- Breathing is inhibited
- UOS relaxes and bolus passes into oesophagus
- UOS contracts and peristalsis moves bolus down
What nerves are involved in the swallowing reflex?
Afferent fibres in CN V/IX/X trigger the reflex
Efferent fibres from CN VII/X/XII lead to swallowing
What are the sections of the larynx?
What are the cartilages of the larynx?
3 single cartilages:
3 Paired cartilages:
Explain the muscles of the larynx?
The intrinsic muscles regulate movement of your vocal folds
The extrinsic muscles move the whole laryngeal complex (e.g. during swallowing) - Infra/supra hyoid muscles
Sensory and motor innervation from vagus nerve via reccurent and external laryngeal nerves
What are the parts of speech?
- Provides the air flow across the vocal chords
- Varies VC position, tension, vibration and length
- Balance of oral/nasal speech
- Action of lips/tongue/jaw produces speech
- Production of stress and emphasis on syllables
What is the pyriform Sinus?
A recess on either side of the laryngeal orifice
Its bounded by the aryepiglottic fold and the thyroid cartilage.