OCB04-2009 Pharynx and Larynx Flashcards
What is the pharynx?
The upper portion of the alimentary canal
Where does the pharynx extend from and to?
From the cranial base to the lower border of the cricoid cartilage where it becomes continuous with the oesophagus
Where is the nasopharynx?
The area above the soft palate and behind the nares
What is the nasopharynx lined with?
Respiratory epithelium with goblet cells and cilia
What is the floor of the nasopharynx formed by?
The soft palate
What is the major part of the posterior wall of the nasopharynx formed by?
Superior constrictor muscles
What is the lateral wall of the nasopharynx formed by?
The opening of the pharyngotympanic tube and lymphoid tissue
What is the roof of the nasopharynx formed by?
More lymphoid tissue, the adenoid or pharyngeal tonsil
What is the oropharynx?
Area inferior to the soft palate
How is the oropharynx separated from the nasopharynx?
Raising of the soft palate
What is the anterior border of the oropharynx?
the palatoglossal and palatopharyngeal arches with the palatine tonsil sitting in between the arches
Why is the oropharynx not lined with respiratory epithelium?
It receives both air and foods so needs to have a more protective function against abrasive foods
What is the oropharynx lined with?
Stratified epithelium
What are the 4 layers of the wall of the pharynx has in common with the rest of the digestive system?
Mucosa
Submucosa
Muscular
Buccopharyngeal fascia
What is the purpose of the submucosa in the pharynx?
It contain a tough fibrous coat that anchors the pharynx to the base of the skull
What does the muscular layer of the pharynx consist of?
5 pairs of muscles forming an outer semi-circular layer, the constrictors and 2 inner longitudnal muscles
What happens to the constrictor muscles during swallowing?
Constrictor muscles contract sequentially as peristaltic waves
What is the nerve supply to the constrictor muscles?
Mostly through the pharyngeal branch of the vagus nerve
The inferior constrictor is also supplied by the recurrent branch of the vagus
What are the superior constrictor muscles?
Form a raphe between the mandible and pterygoid plate to the pharyngeal tubercle of the occipital bone
Where are the middle constrictor muscles?
From the stylohyoid ligament and horns of the hyoid to the pharyngeal raphe
Where are the inferior constrictor muscles?
From the oblique line of the hyoid and cricoid to the junction between the pharynx and oesophagus
What are the longitudinal muscles?
Palatopharyngeus muscles
Stylopharyngeus muscles
Where do the palatophayngeus muscles arise?
From the palatal aponeurosis
Where does the palatopharyngeus insert?
The posterolateral part of the pharynx
Posterior part of the hyoid bone and thyroid cartilage
Where does the stylopharyngeus originate?
The styloid process
What are the functions of the two divisions of the spinal accessory nerve (cnXI)
Cranial division innervates the pharynx and soft palate
Spinal division innervates the sternocleidomastoid and trapezius muscle
What is the motor nerve supply for the pharynx?
All muscles of the pharynx except for the stylopharyngeus are supplied by the pharyngeal branches fo the vagus nerve
Stylopharyngeus is supplied by the glossopharyngeal nerve
What is the sensory supply to the pharynx?
Glossopharyngeal nerve is the main sensory supply with the maxillary division of the Trigeminal supplying the soft paltered roof of the pharynx
Vagus supplying the area around the pharyngeal inlet
What is the blood supply to the pharynx?
by ascending pharyngeal, superior and inferior thyroid, facial and maxillary arteries
What is the venous drainage of the pharynx?
A plexus on the pharynx that communicates with the pterygoid plexus
What is the lymphatic drainge?
Lymph mainly drains into the deep cervical nodes but some posterior ones enter the retropharyngeal nodes
What is the larynx?
Complex unit for voice production as well as an air passageway linking the pharynx with the trachea
It acts as a sphincter to prevent food from entering the trachea
Where is the larynx?
It is anterior to the laryngeal part of the pharynx
Where does the larynx extend from and to?
From the base of the tongue (C3) to the trachea (C6)
What are the walls of the larynx supported by?
cartilage
What are the types of cartilage that support the larynx?
3 large cartilages: thyroid, cricoid and epiglottis
3 small paired cartilages: Arytenoid, cuneiform and corniculate
What are the paired cartilages in the larynx?
arytenoid, cuneiform and corniculate
What are the unpaired cartilages in the larynx?
thyroid, cricoid and epiglottis
What is the thyroid cartilage in the larynx like?
The largest and consists of 2 plates joined anteriorly in the midline
In males, the union give an acute angle and cartilage is a prominent feature in the neck (Adams apple), in females the union is more obtuse
What is the cricoid cartilage in the larynx like?
Cricoid sits immediately below thyroid at level of C6 and is shaped like a signet ring
It is the only cartilage that completely encircles the larynx
What is epiglottis of the larynx like?
A fibroelastic cartilage shaped like a leaf with stem anchored into the angle of the thyroid laminae
What is the arytenoid cartilage of the larynx like?
two pyramid-shaped cartilages lie on the posterior lamina of cricoid cartilage and articulate via a synovial joint
What is the corniculate cartilages?
Tiny elastic cartilages that sit atop the apex of the arytenoid cartilages extending their length
What is the cuneiform cartilage?
Found in aryepglottic folds
What are the ligaments of the larynx?
Thryoidhyoid membrane Vocal ligaments Ventricular ligaments Aryepiglottic ligaments Quadrangular membrane Cricothyoid membrane
What is the origin of the extrinsic muscle sfo the larynx?
They have a remote origin
What is the insertion of the extrinsic muscles of the larynx?
larynx or hyoid bone
What do the extrinisic muses of the larynx do?
Act to move the larynx up or down
During swallowing, they raise the hyoid bone and raise the larynx bringing it forward underneath the tongue so food can enter the oesophagus
Where do intrinsic muscles of the larynx originate and insert?
Into laryngeal cartilages
What occurs when the intrinsic muscles of the larynx contract?
The larynx moves up and under the chin allowing for passive movement of the epiglottis to fold over the larynx
What is the only intrinsic muscles that sits on the outside of the larynx?
Cricothyroid
What are the intrinsic muscles of the larynx?
Posterior cricoarytenoid Lateral cricoarytenoid Transverse cricoarytenoid Vocalis Cricothyroid
What are the 3 separate functions of the intrinsic muscles of the larynx?
Open the rims glottidis to allow the passage of air in or out
Close the vestibule and rim during swallowing to prevent aspiration of food
Control of the tension in the vocal world for phonation
What is the innervation of the larynx?
Laryngeal nerves that branch from th vagus
What motor nerves supply the intrinsic muscles of the larynx?
The external laryngeal nerves target the cricothyroid
The recurrent laryngeal nerve targets the remainder
What is sensory innervation of the larynx?
Internal laryngeal nerves from mucous membrane above the vocal folds, and the recurrent laryngeal nerve from the area below the vocal folds
What arteries supply the larynx?
Superior and inferior thyroid arteries
What veins drain the larynx?
Laryngeal veins that lead into the superior and inferior thyroid veins
What is the lymphatic drainage of the larynx?
By deep cervical nodes
