(12.1+2) Pharynx & Larynx Flashcards
Describe how the Pharynx is subdivided.
- Nasopharynx: base of cranium - soft palate
- Oropharynx: soft palate - superior border of Epiglottis
- Laryngopharynx: superior border of Epiglottis - Inferior border of Cricoid cartilage (anteriorly) & C6 (posteriorly)
Describe how the epithelium of Nasopharynx adapt to its function?
Pseudostratified columnar ciliated + Goblet cells
- Goblet cells secrete mucus catching foreign materials
- Cilia trap and swipe the mucus down to oropharynx to be swallowed
Describe how the epithelium of Laryngopharynx adapt to its function.
Stratified squamous non-keratinised
- Against abrasion during swallowing
The pharyngeal muscles are seperated in two layers, name the muscles and describe their functions.
Outer circular
- Superior & Middle & Inferior Constrictors
- Inferior has two fibres, Thyropharyngeal (upper) & Cricopharyngeal (lower)
- Constrict to push food down
Inner longitudinal
- Stylopharyngeus & Palatopharyngeus & Salpingopharyngeus
- Contract to shorten & widen the pharynx
Describe the phases of swallowing.
1 Voluntary: Tongue pushes food back to oropharynx
2 Pharyngeal: Respiration inhibited + Epiglottis closes glottis + Upper Oesophageal Sphincter relaxed
3 Oesophageal: Peristalsis + Lower Oesophageal Sphincter relaxed
Describe the innervation to the pharynx.
Pharyngeal Plexus: Glossopharyngeal & Vagus & SNS fibres from Superior Cervical Ganglion
Sensory
- Maxillary (CN Vii) -> Nasopharynx
- Glossopharyngeal (CN IX) -> Oropharynx
- Vagus (CN X) -> Laryngopharynx
Motor
- Vagus (CN X) -> all Pharyngeal muscles except
- Glossopharyngeal (CN IX) -> Stylopharyngeus
What arteries supply the Pharynx?
Branches from External Carotid A:
- Ascending pharyngeal
- Lingual
- Facial
- Maxillary
Describe the venous drainages of the Pharynx.
Pharyngeal Venous Plexus -> Internal Jugular Vein
Describe the Lymphoid tissues in the Pharynx
Aggregate become tonsils, forming Tonsillar (Waldeyer’s) Ring at Nasopharynx
- Adenoid tonsil (superior part)
- Tubular tonsils x2
- Palatine tonsils x2
- Lingual tonsil
Recurrent infection may cause chronic enlargement of Adenoid tonsil, suggest some complications of this.
- Breathing difficulties
- Speaking difficulties
- Feeding difficulties
- Blockage of Eustachian tube -> Otits media
- Snoring / Sleep Apnoea
Where does the Palatine tonsils drain into? Where do they locate?
- Jugulo-digastric (Tonsillar) lymph nodes
- Angle of mandible
Suggest why may a Tonsillectomy of the Palatine tonsil be risky.
- Haemorrhage from Internal Jugular Vein
- Internal Carotid A & Glossopharyngeal N pass laterally to Palatine tonsils
A patient came with a viral infection, you found his uvula shifted to the left side. What happened?
- Quinsy = peritonsillar abscess, infection spread from the right Palatine tonsil
Suggest some common sites of where food is likely to be sucked.
- Vallecula = in Oropharynx, region of palatine tonsils
- Piriform fossa = in Laryngopharynx, between epiglottis & tongue
Name 5 important bony structures in the Larynx.
- Hyoid Bone
- Epiglottis
- Thyroid Cartilage
- Cricoid Cartilages
- Arytenoid x2
Describe the movement of Epiglottis.
Contraction of Suprahyoid & Longituidinal Pharyngeal muscles -> elevate Hyoid bone & Larynx -> Epiglottis become horizontal -> closes Glottis
Describe the shape and clinical importance of its bony marking of Thyroid cartilage.
- Laryngeal prominence marks C4
= Bifurcation of Common Carotid A, Carotid Body & Sinus locate
= superior border of larynx
Describe the shape and clinical importance of its bony marking of Cricoid cartilage.
- Signet ring shape
- Marks C6
= inferior border of Hyoid bone
= Junction of Pharynx & Oesophagus
= Junction of Larynx & Trachea
Describe the shape and function of Arytenoid cartilage.
- Pyramid shape
- Attachments for Vocal cords
Where are the vocal cords attached?
Arytenoid Cartilage
Where does the vocal ligament arise from?
Upper free border of the Cricovocal Ligament (Conus Elasticus)
What is the Glottis?
Vocal cords x2 + Rima Glottis
Draw and label a simple diagram showing:
- Epiglottis
- Arytenoid Cartilage
- True Vocal Folds
- False Vocal Folds (What’s another name?)
- Glottis
- Rima Glottis
- Aryepiglottic Folds
- Base of the tongue
http://imgarcade.com/1/intrinsic-muscles-of-the-larynx-superior-view/
False vocal fold = vestibular fold
When are the vocal cords adducted and which muscles are responsible for it? Which nerves innervate this action?
Adduction (closes Rima Glottis) during phonation
- Lateral Cricoarytenoid muscle, Recurrent Laryngeal N
- Cricothyroid muscle, Inferior Laryngeal N
When are the vocal cords abducted and which muscles are responsible for it? Which nerve innervates this action?
Abduction (opens Rima Glottis) during respiration
- Posterior Cricoarytenoid muscle, Recurrent Laryngeal N
Name and describe the function of each intrinsic Laryngeal muscle.
- Aryepiglottic muscle -> Aryepiglottic Folds -> close Laryngeal inlet
- Posterior Cricoarytenoid muscle -> abduct (open) Rami Glottidis -> respiration
- Lateral Cricoarytenoid & Cricothyroid muscles -> adduct (close) Rami Glottidis -> phonation
Describe the innervations of the Larynx.
- External Laryngeal -> motor of Cricothyroid
- Recurrent Laryngeal -> motor of all Intrinsic laryngeal muscles except ^ + sensory below Vocal cords
- Internal Laryngeal -> sensory above Vocal cords
Suggest some reasons causing hoarseness in voice.
- Overuse of voice / benign nodules
- Infection (viral/Streptococcus)
- GORDS
- Apical lung tumour (both sides affected)
- Aortic Aneurysm / Brachial Carcinoma (only left side affected)
Describe the level of descending and looping of Recurrent Laryngeal Nerves on both sides.
- Right: descends to T2 -> loops around R. Subclavian A
- Left: descends to T4 -> loops around Aortic Arch
Describe the arterial supplies to the Larynx.
- External Carotid A -> Superior Thyroid A -> Superior Laryngeal A
- Subclavian A -> Inferior Thyroid A -> Inferior Laryngeal A
Describe the venous drainages of the Larynx.
- Superior Laryngeal V -> Superior Thyroid V -> Internal Jugular V
- Inferior Laryngeal V -> Inferior Thyroid V -> Left Brachiocephalic V
Suggest two ways to manage upper laryngeal obstruction.
- Cricothyroidotomy = opening Cricothyroid membrane in emergency for airways
- Tracheostomy = opening in Trachea
What is a Pharyngeal diverticulum? Why can it be an issue?
- A weak point in the Inferior Constrictor, between Cricopharyngeus & Thyropharyngeus)
- Food builds up in the pouch -> Dysphagia
Describe how the two muscles of the Inferior constrictor of the Pharynx work to prevent intrapharyngeal pressure rising?
- Thyropharyngeus contracts as Cricopharyngeus relaxes
- Allows food bolus to be propelled into the oesophagus
- Prevents trapping of bolus
Which part of the tongue is contained with the Oropharynx? Which nerve receives its sensory information?
- Posterior 1/3
- Glossopharyngeal (CN IX)
Describe the Gag reflex.
Touch back of Oropharynx -> Glossopharyngeal afferents -> Vagus efferents -> pharyngeal muscles contract
Describe how the larynx is divided into three sections.
- Supraglottic space = laryngeal inlet to Vestibular folds
- Glottis = true vocal folds & rima glottis
- Subglottic space = true vocal folds to inferior border of cricoid cartilage
Why does the vocal cords appear pale?
It lacks of submucosa layer, mucosa attaches directly to the vocal ligaments
What bony structure does the Thyroid gland attached to? By what structure?
- Hyoid bone
- Attached by Levator Glandulae Thyroideae at the Isthmus
Why does the Thyroid gland move during swallowing?
- Pretracheal fascia attach to Thyroid & Cricoid cartilages & encloses Thyroid gland
- Suprahyoid muscles elevate Laryngeal skeletons, moving the Thyroid gland with it
Describe the shape of Inferior Thyroid Artery and explain the importance of this shape.
- Tortuous
- Allow elongation as the Thyroid Gland moves during swallowing
Describe the blood supplies to the Thyroid glands.
- Superior Thyroid A
