Session 4: The Pharynx and Larynx Flashcards
What is the pharynx?
A muscular tube which lies in the neck.
- it forms part of the respiratory and gastrointestinal systems.
What occurs during swallowing?
- food in the oral cavity is pushed into the oropharynx by the tongue
- The soft palate rises and closes off the nasopharynx from the oropharynx.
- Food enters the laryngopharynx and the muscles of the pharyngeal wall constrict it to move the food into the oesophagus.
- The epiglottis closes off the laryngeal inlet and prevents food or liquids from entering the larynx.
What is the pharynx composed of?
The pharynx is composed of three parts:
the nasopharynx, the oropharynx, and the laryngopharynx.
- The nasopharynx is posterior to the nasal cavity.
- The oropharynx is posterior to the oral cavity.
- The laryngopharynx is posterior to the larynx (sometimes called the hypopharynx).
What are tonsils?
The tonsils are collections of lymphoid tissue in the upper parts of the pharynx.
What nerves innervate the pharynx?
The pharynx is innervated by sensory fibres from the glossopharyngeal nerve and motor fibres from the vagus nerve.
What is the gag reflex mediated by?
It is mediated by the glossopharyngeal and vagus nerves.
The gag reflex protects the airway.
What happens after a stroke to swallowing ?
swallowing difficulties.
If these swallowing pathways are interrupted, swallowing is dysfunctional, and loss of sensation impairs the cough reflex.
What is the larynx composed of?
The larynx is composed of nine cartilages. Three are unpaired, and three are paired.
Membranes and very small joints connect the cartilages to each other.
What forms the hyoid bones?
- the superior and inferior horns.
- The superior horns attach to the hyoid bone.
- The inferior horns articulate with the cricoid cartilage below.
What is the internal larynx like?
- modified for phonation
- Intrinsic muscles of the larynx move the laryngeal cartilages which in turn move the vocal cords that lie inside the larynx.
Injury to the nerves that innervate the intrinsic laryngeal muscles therefore affect speech.
What are the vocal fold and cords like?
- vestibular folds (false vocal cords) superiorly
- vocal folds (true vocal cords) inferiorly
- A narrow space separates the vestibular and vocal folds.
What are the extrinsic muscles of the ?
Extrinsic muscles - the suprahyoid and infrahyoid muscles.
They do not move the individual cartilages, but rather move the larynx as one with speech and swallowing.
Which muscles affect the vocal cords a?
They include the:
- left and right cricothyroid muscles
- left and right posterior cricoarytenoids
- transverse arytenoid
Which nerves help vocal cords?
Two nerves – both are branches of the vagus nerve:
- The superior laryngeal nerve innervates the cricothyroid muscle and is sensory to the larynx above the vocal folds.
- The recurrent laryngeal nerve innervates all the intrinsic muscles except for the cricothyroid and is sensory to the larynx below the vocal folds.
What is vocal cord palsy?
The recurrent laryngeal nerve lies close to the inferior thyroid artery, which is ligated during thyroidectomy.
The nerve innervates all but one of the intrinsic muscles of the larynx.
If it is injured, the intrinsic muscles of the ipsilateral side do not function and subsequently the vocal cords on the affected side cannot move. When the vocal cords on one side are unable to adduct, hoarseness of the voice results.
What is laryngeal cancer?
Malignancy of the larynx typically presents with a change in the quality of the voice, such as hoarseness.
Visualisation of the larynx - laryngoscopy – is used to examine the larynx and vocal cords