Pharynx-Wilson Flashcards
What is the pharynx?
The pharynx is a fibro-muscular tube that extends from the base of the skull to the beginning of the esophagus at cervical level C6. -best view is the saggital view -long tube of mostly muscles and surrounded by fascia
What are the general functions of the pharynx?
1) Upper end of digestive system (tube for eating); -part of the digestive system (connecting oral cavity with esophagus) -swallowing has 3 phases: grinding food up and mixing it with saliva ; you take your tongue and push food back to your pharynx 2) Upper end of respiratory system (tube for breathing); if you have a cold you can’t breathe through your nose but you can breathe through your mouth. You have the POTENTIAL OF CHOKING of food due to the dual function of pharynx for eating and breathing. 3) First line of lymphatic defense against infectious invasion into respiratory and digestive system
HUMANS HAVE AN ELONGATED PHARYNX NECESSARY FOR SPEECH
the position of the pharynx changes with evolution : descends and elongates -it’s important to get the pharynx in the neck for speech production -this has a cost though which is the potential for choking Because of the development of the oropharynx, humans are uniquely prone to choking
Because of its length we divide it into 3 parts
The Pharynx is Divided into 3 Regions: dictated by what is found anterior to the structure Nasopharynx -1 part behind the nasal cavity Oropharynx - 2 directly behind the oral cavity Laryngeal -3 directly behind the larynx
Anterior Boundaries of Pharynx
Nasopharynx Posterior Choanae -once you go through the choana you are in the nasopharynx Oropharynx Palatoglossal Arch -the innervation of the pharynx; when you are anterior to this arch you are in the oropharynx; once food is transferred after this arch you stimulate CN IX which will???; stimulate gag reflex behind this arch ????
SENSORY INNERVATION
upper part of nasopharynx is innervated by V2 (pharyngeal branch) lower part of oropharnx is CN X everything below the epiglottis is innervated by CN X vagus nerve in terms of its composition is primarily PS; fibers transferred to mucosa lining the laryngeal pharynx
The Right & Left Palatoglossal Folds Form an Arch That Separates Oral Cavity From Oropharynx
a mucous fold is a muscle of the same name (Palatoglossal muscle)??? -anterior to the arch is the V2 -behind the arch is CN IX; activate the involuntary phase of swallowing and gag reflex
Touching Posterior to the Palatoglossal Arch Evokes the Gag Reflex
everything behind uvula will initiate a gag reflex
GAG REFLEX
-you can observe . the elevation of the soft palate -it is a symmetrical appearance
Vagal nerve damage (motor limb)
touch in the oropharynx -flaccid paralysis of the muscle of the soft palate -lack of elevation of the soft palate -uvula deviation towards the normal side
The Muscles of the Pharynx Are Derived From the 4th Pharyngeal Arch
esophagus is skeletal muscle ??? They are Organized Into 2 Groups: 1) outer circular (3 muscles) 2) inner longitudinal (3 muscles)
outer circular (3 muscles)
-called constrictors Superior Pharyngeal Constrictor -originates from pterygomandibular raphe that goes from the pterygoid plate to the mandible; there is a muscle anterior to this raphe called buccinator Middle Pharyngeal Constrictor -originates from hyoid bone Inferior Pharyngeal Constrictor -originates from larynx; attaches to thyroid and cricoid cartilage through these gaps structures can come and go from outside of the pharynx to inside of the pharynx Has a 4th technically
cricopharyngeus muscle
does not have a separate origin or any fascia surrounding it making it different -anatomically speaking is part of the constrictors; it is the most inferior part; the inferior fibers of the inferior constrictor are called the “cricopharyngeus muscle” cricopharyngeus -tonically constricted; this muscle is under contraction all the time because we’re breathing -prevents air from entering stomach during breathing -relaxes during swallowing; has to relax to allow food to transfer from pharynx to esophagus
During Swallowing, Constrictors Produce a Peristaltic Wave
-tongue pushes food up against hard palate and pushes it back -once food passes the fold CN IX is triggered -goes all the way to the esophagus with constrictors squeezing or milking the food ????
The conically shaped constrictor muscles overlap so that the lower muscle constricts around the bolus and the muscle above.
As you swallow food, as the food is being squeezed from one constructor to another. There is a period of transition. The muscle contract at the same time for food to go down ?????This prevents the bolus from being squeezed out laterally during swallowing. Theoretical: If the timing of contraction of the muscle are not the same food can go in either direction: -food in the neck instead of the esophagus
Pharyngo-Esophageal (Zenker’s ) Diverticulum : the real
During swallowing peristaltic wave produce a lot of pressure to push food down to esophagus. If you have a weakened wall of pharynx, this food instead of going to the esophagus will form a diverticulum that makes the food go to the neck. clinical consequences: -puch gets larger and larger blocking the esophagus making swallowing much more difficult (dysphasia) -through swallowing this the tissues around the pouch is elastic and so when you’re swallowing there will ???squeeze food back to the laryngeal pharynx resulting in regurgitation of food -halitosis: funky breath Diagnosis: -Deglutition = Swallowing -Dysphagia = Swallowing Dysfunction -have patient to swallow water and hear the water gurgling down (time how long it takes) -10 second lag may indicated dysphagia Treatment: staple the pouch and remove the food
3 longitudinal muscles functions
-shorten the length of pharynx to reduce probability that food will go into esophagus instead of respiratory system -when they contract they expand the pharynx laterally
3 longitudinal muscles
- Salpingopharyngeus: -attaches to the eustachian tube and is innervated by CN X 2. Palatopharyngeus CN X another fold or arch that is in the oropharynx entirely and goes from soft palate to pharynx 3. Stylopharyngeus CN IX goes between the superior and middle constrictor; innvervated by CN IX (third pharngeal arch) ???
Smooth muscles of soft palate
-uvula -levator veli palatini: elevates the soft palate during swallowing -tensor veli palatini: deeper and more anterior; ????bony projection coming off the lateral pterygoid plate; around this bone is where the muscle makes a 90 degree turn and attaches to the soft palate: innervated by CN V3; pulls the palate laterally -pterygoid hamulus ??????? palatoglossus : serves as the boundary btw oral cavity and oropharynx palatopharyngeus?????
Vagus nerve innervation of the soft palate
-cell bodies of vagus nerve is found in the nucleus ambiguus (closed medulla) along the reticular formation SVE fibers of CN X originate from nucleus ambiguus open medulla=inferior olivary complex spinothalamic tract: pain/temp/touch stroke in lateral part of the medulla would result in ???? NA location is important in determiing in whether the stroke is medial or lateral medulla.
What is the most important structure in the nasopharynx?
auditory tube: -the opening; is not flat but has a mucosal ridge around it called torus tubarius -salpingo- pharyngeal fold nucleus fold that extends from auditory tube to pharynx -???gap is the pharyngeal recess
Auditory tube
-The auditory tube connects the middle ear and nasopharynx -It permits air pressure in the middle ear cavity to equalize to atmospheric pressure, ie. ventilates the middle ear cavity. Atm pressure is always changes and can make the TM to bulge inwardly or outwardly. When pressure is equal TM is in neutral position which maximizes hearing. -It provides a pathway for infection to spread from nasopharynx to the middle ear through the euchastian tube (auditory); otitis media
The auditory tube opens during swallowing
-most often closed -really only opened when you swallow The auditory tube opens during swallowing (note: attachment of muscles to the pharyngeal tube) tensor veli palatini and salpingopharyngeus muscles are attached to the auditory tube which opens the lumen of the tube when muscles contracts
PHARYNGEAL TONSILS
serves as the first line of lymphatic invasion of bacteria into upper parts of digestion and respiratory system Pharyngeal Tonsil Tubal Tonsils: surround the auditory tube they are loose aggregates of LT or nodules; they not encapsulated to a distinct structure swelling of throat lead to fullness in ear because of blockage of air leading into the oral cavity ?????? Adenoids as they get larger will prevent mouth breathing. ?????
ADENOID FACIES
1) chronic mouth breather 2) dull, dimwitted appearance 3) drying of gingivae (mucosa around oral cavity), leading to gingivitis the tongue is important for the development of dental arches aligning the hard palate and teeth well ????
SOFT PALATE
-A moveable, muscular septum -sometimes it hangs down or laterally
During swallowing, soft palate swings posteriorly & superiorly
-to seal off the nasopharynx from the oropharynx -produces a partition that separates the nasopharynx and oropharynx -due to this partition food only has one way to go which is towards the esophagus
Paralysis of the soft palate
-soft palate fails to form a partition due to vagal nerve lesion??? -results in a regurgitation of food into the nasal cavity during swallowing
Neurotoxins produced by Corynebacterium Diphtheriae may result in paralysis of the soft palate
-Neurotoxins kill nerve endings of the vagal nerve
UVULAR PARALYSIS
Uvula is drawn to the opposite side of the lesion when the patient says, “A-AH”
During sucking, it swings anteriorly & inferiorly to seal off the oral cavity from the oropharynx
-not posteriorly like in swallowing -forms a seal with the back of the tongue -you expand the size of the oral cavity?????? -when a baby suckles they can breath at the same time???? the pathway for respiration remains open making breathing possible during sucking A vacuum is produced by expanding the volume of a sealed oral cavity