Lecture 6 - Chewing and swallowing II Flashcards
The palate: what is it and what is it comprised of?
Structure forming the roof of the mouth
- Hard palate
- Soft palate
Hard palate: what is it, what innervates it, and what parts are there to it and what are their relations?
Structure forming the roof of the mouth and floor of the nose
Sensory innervation – Maxillary division of trigeminal nerve
Bony skeleton:
* Palatine process of maxilla
* Horizontal process of palatine bone
Mucosa:
* Oral surface - keratinised stratified squamous epithelium
* Nasal surface – respiratory epithelium
* Underlying lamina propria – contains blood vessels and nerves
(Rugae – Function?) ?
Soft palate: what is it, what innervates it, and what parts are there to it and what are their relations?
Consists of muscle covered with non-keratinised stratified squamous epithelium & lamina propria
Sensory innervation – branches of the maxillary division of the trigeminal
Motor innervation -
* Pharyngeal plexus (Vagus)
* Except tensor veli palatini – mandibular division of trigeminal nerve
Muscles:
* Tensor veli palatini
* Levator veli palatini
* Palatoglossus
* Palatopharyngeus
* Muscularis uvulus
Tensor veli palatini: what is it, what is its origin, what is its insertion, and what is its action?
Thin, triangular muscle of the head that tenses the soft palate and opens the Eustachian tube to equalise pressure in the middle ear
Origin: auditory tubes & petrous part of temporal bone
Insertion: palatine aponeurosis
Action: elevates soft palate & equalises pressure in middle ear
Levator veli palatini: what is it, what is its origin, what is its insertion, and what is its action?
The primary muscle responsible for velar elevation
Origin - auditory tubes & sphenoid bone
Insertion - palatine aponeurosis
Action - tenses soft palate & equalises pressure in the middle ear
Palatoglossus: what is it, what is its origin, what is its insertion, and what is its action?
Among the four extrinsic muscles of the tongue and the paired muscles of the soft palate. The right and left palatoglossus muscles create ridges in the lateral pharyngeal wall, referred to as the palatoglossal arches
Origin: palatine aponeurosis
Insertion: posterolateral aspect of the tongue
Action: elevates the tongue and narrows the oropharyngeal isthmus
Palatopharyngeus: what is it, what is its origin, what is its insertion, and what is its action?
Muscle of both the soft palate and the pharynx
Origin: palatine aponeurosis
Insertion: lateral pharyngeal wall
Action: elevates the pharynx
Muscularis uvulus: what is it, what is its origin, what is its insertion, and what is its action?
Bilaterally muscle of the soft palate
Soft palate: what are its functions?
Seals off the nasopharynx in swallowing and speech
Narrows oropharyngeal isthmus, elevates tongue and assists in elevation of the pharynx during swallowing
Oropharyngeal isthmus
Leads from the oral cavity into the pharynx
Boundaries:
* superior – soft palate
* Inferior – posterior 1/3 of tongue
* Lateral – palatoglossal arch
Pharynx: what is it, what is its location, what are its anterior connections, and what divisions are there?
Funnel-shaped fibromuscular tube
Extends from base of skull to oesophagus
Oropharynx
Anterior openings for the nose, mouth and larynx
Divisions – nasopharynx, oropharynx & laryngopharynx
Nasopharynx: where is it located, what cells are present, what is its innervation, and what are its features?
Extends from the nasal choanae to the tip of the soft palate
Lined by pseudostratified ciliated columnar epithelium
Sensory innervation; maxillary division of trigeminal & glossopharyngeal
Important features
* Ostium of the auditory (eustachian) tube
* Pharyngeal tonsils (adenoids)
* Tubal tonsils
Oropharynx: where does it extend, what is it comprised of, and where does the posterior 1/3 run?
Extends from the tip of the soft palate to the superior aspect of the epiglottis
Anteriorly it extends from the oropharyngeal
isthmus - it therefore contains:
* palatoglossal folds
* palatopharyngeal folds
* tonsillar recess and palatine tonsils
The posterior 1/3 of the tongue runs vertically in
the anterior wall - lingual tonsils
Waldeyer’s ring: what is it, what cells are present, and what is its innervation?
Consists of four tonsillar structures (pharyngeal, tubal, palatine, and lingual tonsils)
Lined by non-keratinised stratified squamous epithelium
Sensory innervation; maxillary division of
trigeminal & glossopharyngeal
Laropharynx: where does it extend from, what are its anterior relations,
Extends from the epiglottis to the oesophagus
Laryngeal inlet located anteriorly - bounded by the aryepiglottic folds and the
epiglottis
Piriform recess lies lateral to aryiepiglottic
fold – significance?
Sensory innervation; glossopharyngeal &
vagus
Lined by stratified non-keratinised squamous epithelium
Pharynx muscles: constrictor and longitudinal muscles
Constrictor muscles:
* Superior
* Middle
* Inferior
Longitudinal muscles:
* Stylopharyngeus
* Salpingopharyngeus
* Palatopharyngeus
Constrictor muscles: what are they, what do they do, how are they innervated, where are their origins, and what are their insertions?
Three pairs of muscles (superior, middle, and inferior) that overlap each other and meet posteriorly at the pharyngeal raphe
They contract sequentially to push bolus of
food into oesophagus
All are innervated by the pharyngeal plexus (vagus)
Superior:
* Origin - sphenoid bone, mandible & pterygomandibular raphe
* Insertion: Pharyngeal tubercle & pharyngeal raphe
Middle:
* Origin - hyoid bone & stylohyoid ligament
* Insertion: pharyngeal raphe
Inferior (Two parts):
* Thyropharyngeus originates from the thyroid cartilage
* The cricopharyngeus originates from the cricoid cartilage
* Insertion: pharyngeal raphe
Superior pharynx constrictor muscles: what are their origin and insertion?
Origin - sphenoid bone, mandible & pterygomandibular raphe
Insertion: Pharyngeal tubercle & pharyngeal raphe
Middle pharynx constrictor muscles: what are their origin and insertion?
Origin - hyoid bone & stylohyoid ligament
Insertion: pharyngeal raphe
Inferior pharynx constrictor muscles: what are their origin and insertion?
The thyropharyngeus originates from the thyroid cartilage
The cricopharyngeus originates from the cricoid cartilage
Insertion: pharyngeal raphe
Longitudinal muscles: what are they, what do they do, how are they innervated, where are their origins, and what are their insertions?
Three pairs of muscles that overlap each
other and meet posteriorly at the pharyngeal raphe
- Shorten and widen the pharynx
- Elevate the pharynx and larynx
- Open the auditory tube
All are innervated by the pharyngeal plexus (vagus)
Superior - Salpingopharyngeus
Origin: auditory tube
Insertion: lateral pharyngeal wall
Innervation: pharyngeal plexus (Vagus)
Middle - Stylopharyngeus:
Origin: styloid process of temporal
bone
Insertion: posterior aspect of the
thyroid cartilage and the lateral
pharyngeal wall
Innervation: glossopharyngeal nerve
Inferior - Palatopharyngeus:
Origin: Palatine aponeurosis
Insertion: posterior aspect of the thyroid
cartilage & lateral pharyngeal wall
Innervation: pharyngeal plexus (Vagus)
Superior pharynx longitudinal muscles: what are their origin and insertion?
Superior - Salpingopharyngeus
Origin: auditory tube
Insertion: lateral pharyngeal wall
Innervation: pharyngeal plexus (Vagus)
Middle pharynx longitudinal muscles: what are their origin and insertion?
Middle - Stylopharyngeus:
Origin: styloid process of temporal
bone
Insertion: posterior aspect of the
thyroid cartilage and the lateral
pharyngeal wall
Innervation: glossopharyngeal nerve
Inferior pharynx longitudinal muscles: what are their origin and insertion?
Inferior - Palatopharyngeus:
Origin: Palatine aponeurosis
Insertion: posterior aspect of the thyroid
cartilage & lateral pharyngeal wall
Innervation: pharyngeal plexus (Vagus)
Pharyngeal plexus: what is it, what does it consist of, where it it located, and what is it superior to?
Nerve plexus consisting:
* motor fibres from the vagus
* sensory fibres from glossopharyngeal
* parasympathetic fibres from the glossopharyngeal
* sympathetic fibres from the superior cervical
ganglion
Located in the buccopharyngeal fascia
Superficial to constrictor muscles
Oesophagus: what is it, where does it extend from, what muscles is it involved with, and what does it pass through?
Muscular tube - extends from laryngopharynx
to the stomach (levels C6 –T10)
- Upper third skeletal muscle
- Middle third mixed muscle
- Lower third smooth muscle
- Passes through the diaphragm at the oesophageal hiatus (level T10)
- Passes through the neck, thorax and abdomen
Oesophagus microscopic anatomy: what layers does its wall contain?
The wall of the oesophagus consists of four layers:
* Mucosa - Lined by non-keratinised stratified
squamous epithelium
* Submucosa - Contains mucous glands, blood vessels, lymphatics & nerves
* Muscularis externa
* Adventia - The oesophagus is intraperitoneal therefore it is covered with an adventitia
Oesophageal vascular supply and lymphatic drainage
Upper third:
* Arterial - Subclavian artery -> inferior thyroid artery
* Vein - inferior thyroid vein -> brachiocephalic vein
* Lymph - Deep cervical nodes
Middle third
* Arterial - descending aorta
* Vein - azygos veins -> superior vena cava
* Lymph - Superior & posterior mediastinal nodes
Lower third:
* Arterial - Coeliac trunk -> left gastric artery
* Vein - left gastric veins -> portal system
* Lymph - Coeliac nodes
Oesophagus innervation
Oesophageal plexus:
Parasympathetic – vagus nerve
Sympathetic – sympathetic trunks/chains
