Session 11 - Pharynx Flashcards
What is the pharynx?
Superior, expanded part of the Alimentary System, posterior to the nasal and oral cavities and extending inferiorly past the larynx
What are the three parts of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
Where does the pharynx extend to and from?
The Cranial Base to the Inferior Border of the Cricoid Cartilage Anteriorly and the Inferior Border of C6 Vertebra Posteriorly
Where is pharynx widest?
5cm opposite the hyoid
Where is pharynx narrowest?
At its inferior end, where it is continous with oesophagus
Where is nasopharnx found?
Posterior to the nose and super to soft palate
Cranial base -> Soft palate
What is anterior and posterior nasopharynx?
Anterior - Posterior nasal chonchae
Posterior nasopharyngeal tonsils
Where is oropharynx found?
Soft palate -> Superior edge of epiglottis
What is anterior and post to oropharynx?
Oral cavity - Ant
Posterior - C2, C3
What is the content of the oropharynx?
Palatine tonsils
A&P tonsillar pillar
What is Walder’s ring?
i
Where does laryngopharnynx chill?
Superior edge of epiglottis
Level of inferior edge of cricoid cartilage
A&P laryngopharynx?
A - Larynx
P - C3- C6
Opening laryngopharynx?
A - Larynx
P - Oesophagus
What is function of nasopharynx?
Respiratory
What significant structure is found in nasopharynx?
Tonsilar ring, which aggregate to form adenoids.
These can swell during URT and block Eustachian tube, leading to otitis media.
What is epithelium of the nasopharynx
Pseudostratified Ciliated Epithelium with Goblet Cells
What is function of oropharynx?
Digestive function
What is the epithelium of oropharynx?
Stratified Squamous Epithelium non-Keratinised
What is epithleium laryngopharynx?
Stratified Squamous Epithelium non-keratinised
What are the pharyngeal muscles?
An incomplete outer circular and inner longitudinal muscle layers
Outline vertebral levels
C1 - Hard palate C2 - Angle of mandible C3 - Hyoid bone C4,C5 - Thyroid cartilage C6 - Cricoid cartilage
What does C6 signify?
Point of transition to thorax
What is the foramen of winslow?
T12
What antiboides are produced by lymphoid tissue?
IgA, IgG and IgM
What is the outer circular muscle layer of the pharynx made up of?
o Superior Constrictor
o Middle Constrictor
o Inferior Constrictor
Lower horizontal fibres known as Cricopharyngeus
Where does the outer circular muscle of the pharynx attach?
The midline raphe
What are the inner longitudinal muscles of the pharynx?
o Stylopharyngeus
o Palatopharyngeus
o Salpingopharyngeus
What is a pharyngeal pouch?
Posterior herniation of pharyngeal mucosa
Occurs through killians dehiscence (between inferior constrictor and cricopharyngeus)
Why do pharyngeal pouches occur?
Weak area
Incoordination of pharyngeal phase of swallowing
Cricopharyngeal spasms
Outline the innervatiuon of the pharynx?
Innervation of the Pharynx is by the Pharyngeal Plexus of nerves. This is formed by branches of the Vagus (CN X) and Glossopharyngeal (CN IX) nerves along with sympathetic fibres from the Superior Cervical Ganglion.``
What is the sensory innervation of the pharynx?
o Glossopharyngeal Nerve
o Nasopharynx is via the Opthalmic and Maxillary divisions of the Trigeminal Nerve (CN V1+2)
Where do bifurcations occur?
– 4
Carotid bifurcates at C4
Trachea bifurcates at T4
Aorta bifurcates at L4
What is the motor innervation of the pharynx?
o Vagus Nerve (CN X)
o Exception to this is the Stylopharyngeus Muscle
Glossopharyngeal Nerve (CN IX)
What are the three phases of swallowing?
Voluntary phase
Pharyngeal phase
Oesophageal phase
What happens in the voluntary phase?
o Tongue moves the bolus back onto the pharyn
What happens in the pharyngeal phase
o Afferent information from pressure receptors in the palate and anterior pharynx reaches the swallowing centre in the brain stem.
o A set of movements is triggered
Inhibition of breathing
Raising of the larynx – Suprahyoid and Longitudinal Muscles
Closure of the glottis
Opening of the upper oesophageal ‘sphincter’
What happens in the oesophageal phase?
o The muscle in the upper third of the oesophagus is voluntary striated muscle under somatic control
o The muscle of the lower two thirds is smooth muscle under control of the parasympathetic nervous system.
o A wave of peristalsis sweeps down the oesophagus, propelling the bolus to the stomach in ~9 seconds.
o Coordinated by extrinsic nerves from the swallowing centre of the brain
o Lower oesophageal ‘sphincter’ opens
What is the blood supply of the pharynx?
o Ascending Pharyngeal Artery
o Lingual Artery
o Facial Artery
o Maxillary Artery
What is the venous drainage of the pharynz?
Venous drainage of the Pharynx is via the Pharyngeal Venous Plexus Internal Jugular Vein.
WHat is the gag reflex? What is its innervation?
The gag reflex tests pharyngeal innervation and musculature. It is conducted by touching the back of the oropharynx, which result in a reflex contraction of the pharyngeal muscles (makes the person gag). o Afferent Pathway Glossopharyngeal Nerve (CN IX) o Efferent Pathway Vagus Nerve (CN X)
What are the adenoids?
o Sub-epithelial collection of lymphoid tissue
o Junction of roof and poster wall of Nasopharynx
o Maximal size between 3 – 8 years then regress
o Enlarge with viral / bacterial infections
o Recurrent infections may lead to chronically enlarge adenoids
`
What are the clinical features of enlarged adenoids?
o Nasal obstruction
o Mouth breathing, nasal speech
o Feeding difficulty (especially infants)
o Snoring / Obstructive Sleep Apnoea
o Block the opening of the Eustachian Tube
What are the palatine tonsils?
o Lie in the Tonsillar fossa between two arches
What are the anterior palatine tonsils?
Anterior – Palatoglossal Arch
• Boundary between mouth and oropharynx
What are the posterior palatine tonsils?
Posterior – Palatopharyngeal Arch
• Contains the Palatopharyngeus Muscle that blends with walls of the pharynx
What type of epithelium covers the palatine tonsils?
o Lymphoid tissue covered by squamous epithelium
What is lymphatic drainage of the palatine tonsils?
Jugulo-Digastric noce
Where does bleeding come from in tonsilectomy?
Potential for bleeding as the palatine tonsils are very vascular
Bleeding often from the large External Palatine Vein
What are two important structures near tonsils which must be remembered in a tonsilectomy?
Internal Carotid Artery and Glossopharyngeal Nerve lie just lateral to Tonsillar fossa
What is quinsy?
Peritonsilar abscess
Where does food become stuck in the oro pharynx/
o Vallecula
Mucosal Pouch between the base of the tongue and epiglottis
o Base of tongue
o Region of palatine tonsil
Where does food become stuck in the laryngopharynx?
o Piriform Fossa
Mucosal Recess between the central part of the larynx and lateral lamina of the thyroid cartilage
o Cricopharyngeus
