Lecture 6 - Chewing and swallowing II

Question 1

The palate: what is it and what is it comprised of?

Answer 1

Structure forming the roof of the mouth

• Hard palate
• Soft palate

Question 2

Hard palate: what is it, what innervates it, and what parts are there to it and what are their relations?

Answer 2

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?) ?

Question 3

Soft palate: what is it, what innervates it, and what parts are there to it and what are their relations?

Answer 3

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

Question 4

Tensor veli palatini: what is it, what is its origin, what is its insertion, and what is its action?

Answer 4

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

Question 5

Levator veli palatini: what is it, what is its origin, what is its insertion, and what is its action?

Answer 5

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

Question 6

Palatoglossus: what is it, what is its origin, what is its insertion, and what is its action?

Answer 6

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

Question 7

Palatopharyngeus: what is it, what is its origin, what is its insertion, and what is its action?

Answer 7

Muscle of both the soft palate and the pharynx

Origin: palatine aponeurosis

Insertion: lateral pharyngeal wall

Action: elevates the pharynx

Question 8

Muscularis uvulus: what is it, what is its origin, what is its insertion, and what is its action?

Answer 8

Bilaterally muscle of the soft palate

Question 9

Soft palate: what are its functions?

Answer 9

Seals off the nasopharynx in swallowing and speech

Narrows oropharyngeal isthmus, elevates tongue and assists in elevation of the pharynx during swallowing

Question 10

Oropharyngeal isthmus

Answer 10

Leads from the oral cavity into the pharynx

Boundaries:
* superior – soft palate
* Inferior – posterior 1/3 of tongue
* Lateral – palatoglossal arch

Question 11

Pharynx: what is it, what is its location, what are its anterior connections, and what divisions are there?

Answer 11

Funnel-shaped fibromuscular tube

Extends from base of skull to oesophagus
Oropharynx

Anterior openings for the nose, mouth and larynx

Divisions – nasopharynx, oropharynx & laryngopharynx

Question 12

Nasopharynx: where is it located, what cells are present, what is its innervation, and what are its features?

Answer 12

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

Question 13

Oropharynx: where does it extend, what is it comprised of, and where does the posterior 1/3 run?

Answer 13

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

Question 14

Waldeyer’s ring: what is it, what cells are present, and what is its innervation?

Answer 14

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

Question 15

Laropharynx: where does it extend from, what are its anterior relations,

Answer 15

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

Question 16

Pharynx muscles: constrictor and longitudinal muscles

Answer 16

Constrictor muscles:
* Superior
* Middle
* Inferior

Longitudinal muscles:
* Stylopharyngeus
* Salpingopharyngeus
* Palatopharyngeus

Question 17

Constrictor muscles: what are they, what do they do, how are they innervated, where are their origins, and what are their insertions?

Answer 17

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

Question 18

Superior pharynx constrictor muscles: what are their origin and insertion?

Answer 18

Origin - sphenoid bone, mandible & pterygomandibular raphe

Insertion: Pharyngeal tubercle & pharyngeal raphe

Question 19

Middle pharynx constrictor muscles: what are their origin and insertion?

Answer 19

Origin - hyoid bone & stylohyoid ligament

Insertion: pharyngeal raphe

Question 20

Inferior pharynx constrictor muscles: what are their origin and insertion?

Answer 20

The thyropharyngeus originates from the thyroid cartilage
The cricopharyngeus originates from the cricoid cartilage

Insertion: pharyngeal raphe

Question 21

Longitudinal muscles: what are they, what do they do, how are they innervated, where are their origins, and what are their insertions?

Answer 21

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)

Question 22

Superior pharynx longitudinal muscles: what are their origin and insertion?

Answer 22

Superior - Salpingopharyngeus
Origin: auditory tube
Insertion: lateral pharyngeal wall
Innervation: pharyngeal plexus (Vagus)

Question 23

Middle pharynx longitudinal muscles: what are their origin and insertion?

Answer 23

Middle - Stylopharyngeus:
Origin: styloid process of temporal
bone
Insertion: posterior aspect of the
thyroid cartilage and the lateral
pharyngeal wall
Innervation: glossopharyngeal nerve

Question 24

Inferior pharynx longitudinal muscles: what are their origin and insertion?

Answer 24

Inferior - Palatopharyngeus:
Origin: Palatine aponeurosis
Insertion: posterior aspect of the thyroid
cartilage & lateral pharyngeal wall
Innervation: pharyngeal plexus (Vagus)

Question 25

Pharyngeal plexus: what is it, what does it consist of, where it it located, and what is it superior to?

Answer 25

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

Question 26

Oesophagus: what is it, where does it extend from, what muscles is it involved with, and what does it pass through?

Answer 26

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

Question 27

Oesophagus microscopic anatomy: what layers does its wall contain?

Answer 27

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

Question 28

Oesophageal vascular supply and lymphatic drainage

Answer 28

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

Question 29

Oesophagus innervation

Answer 29

Oesophageal plexus:
Parasympathetic – vagus nerve
Sympathetic – sympathetic trunks/chains