Throat Flashcards
What are the 2 parts of the oral cavity?
Oral vestibule (between lips and teeth) Oral cavity proper
What are the boundaries of the oral cavity?
Lips to palatoglossal arch
Palate to floor of mouth/tongue
Buccal mucosa
How does the parotid duct reach the oral cavity?
Pierces the buccinator muscle then opens into oral cavity on inner surface of cheek opposite maxillary 2nd molar
Where is the submandibular duct?
Lies superior to the digastric muscle, each submandibular gland is divided into superficial and deep lobes, which are separated by the mylohyoid muscle
What does the lingual nerve supply?
General somatic afferent innervation from the anterior 2/3rds of the tongue
Carries nerve fibres that are not part of the trigeminal nerve including chorda tympani nerve (facial) - provides taste to anterior 2/3rds of tongue
What are the functions of the oral cavity?
Taste Mastication (teeth, tongue) Speech (tongue, cheek, lips) Digestion (salivary enzymes) Swallowing (tongue, hard and soft palate)
Where does the anterior 2/3rds of the tongue derive from?
1st branchial arch
What innervates the anterior 2/3rds of the tongue?
Lingual nerve (sensation) Chorda tympani (taste)
Where does the posterior 1/3rd of the tongue derive from?
3rd branchial arch
What innervates the posterior 1/3rd of the tongue?
CN IX
What are the different papillae found on the tongue?
Filliform - do not contain taste buds
Fungiform - scattered throughout dorsum of tongue
Folliate - rudimentary
Circumvallate - row just anterior to sulcus terminalis
What do intrinsic muscles do in the tongue?
Alter shape
What do extrinsic muscles do in the tongue?
Alter position
What is the nerve supply of the muscles in the tongue?
CN XII - hypoglossal supplies all but palatoglossus (supplied by pharyngeal plexus - CN iX - X)
What are the extrinsic muscles of the tongue?
Genioglossus
Styloglossus
Hypoglossus
Palatoglossus
What are the functions of the tongue?
Taste
Mastication
Swallowing
Speech
What are the 4 muscles involved in mastication?
Lateral pterygoid
Medial pterygoid
Temporalis
Masseter
What supplies the muscles of mastication?
CN V3
What is the function of the muscles of mastication?
Act on TMJ - food positioned between teeth for grinding by action of tongue and cheek
What are the boundaries of the oropharynx?
Lower border of soft palate to upper margin of epiglottis
Palatoglossal arch to posterior pharyngeal wall
Lateral = facial pillars and palatine tonsils
What type of epithelium is in the oropharynx?
Stratified, non-keratinised squamous
What is the nerve supply of the oropharynx?
Pharyngeal plexus (CN IX and X)
What is the blood supply of the hypopharynx?
Superior thyroid artery
Lingual artery
Ascending pharyngeal artery
What is the nerve supply of the hypopharynx?
Pharyngeal plexus
What are the boundaries of the hypopharynx?
Superior margin of epiglottis to lower border of cricoid cartilage
Continuous with oesophagus
Anterior wall = back of larynx
What are the 3 subsites of the hypopharynx?
Pyriform sinus
Post-cricoid area
Posterior pharyngeal wall
What are the 3 phases of swallowing?
Oral phase (voluntary)
Pharyngeal
Oesophageal
What is the oral phase of swallowing?
Tongue propels food in pharynx
Triggers swallowing reflex
What is the pharyngeal phase of swallowing?
Soft palate pulled upwards
Epiglottis covers larynx, larynx moves upward
Upper oesophageal sphincter relaxes
Respiration is reflex inhibited
What is the oesophageal phase of swallowing?
Once bolus passed UOS, sphincter constricts
Bolus propelled downwards by peristaltic motion, reflex via myenteric plexus
What is myenteric plexus?
Provides motor innervation to both layers of the tunica muscularis - both sympathetic and parasympathetic input
What are the functions of the larynx?
Part of respiratory tract
Voice
Swallowing
What are the 3 parts of the larynx?
Supraglottis
Glottis
Subglottic
Where is the supraglottis?
Extends from superior tip of epiglottis to floor of ventricular fold
Where is the glottis?
Begins superiorly at true vocal fold and extends inferiorly to horizontal plane 5mm inferior to the vocal cord
Where is the subglottis?
Begins 5mm below the free edge of the true vocal cord and proceeds to the inferior border of the cricoid cartilage
What are the 7 segments of cartilages in the larynx?
Cricoid
Thyroid
Epiglottis
Paired arytenoid cartilages (corniculate and cuneiform)
What are the extrinsic muscles of the larynx?
Infrahyoid
Suprahyoid
Thyrohyoid
What is the difference between the roles of extrinsic and intrinsic muscles in the larynx?
Extrinsic = move the entire laryngeal complex Intrinsic = regulate movement of vocal folds
What is the motor innervation of the larynx?
All intrinsic muscles are supplied by recurrent laryngeal nerve except for cricothyroid muscle (external laryngeal nerve)
What is the sensory innervation of the larynx?
Supraglottic: internal laryngeal nerve
Glottic + subglottic: recurrent laryngeal nerve
Why is the left recurrent laryngeal nerve at a higher risk of injury during operative chest procedures?
It has a longer course - it loops around the aortic arch instead of right subclavian
Where does the superior laryngeal nerve divide into external and internal branches?
At the level of the greater cornu of the hyoid
What is the role of the internal superior laryngeal nerve branch?
Travels with superior laryngeal artery through the thyrohyoid membrane and allows supraglottic sensation and increased airway protection
What is the role of the external superior laryngeal nerve branch?
Supplies subglottic mucosal sensation and motor fibers to the cricothyroid muscle
What are the 5 steps of speech?
- Respiration (source of energy)
- Phonation (different VC position, tension, vibration and length)
- Resonation (oral/nasal balance, depend on nasopharynx, nasal and oral cavity)
- Articulation (production of speech)
- Prosody (syllable stress + emphasis, speech tone)
What is the pulmonary phase of speech?
Creates energy flow with inflation and expulsion of air. Provides larynx with a column of air
What is the laryngeal phase of speech?
Vocal folds vibrate at certain frequencies to create sound that is then modified in the supraglottic/oral/nasal phase
How are words formed?
By the action of the pharynx, tongue, lips and teeth
What is prosody?
Rhythm, stress and intonation of speech
Associated with areas 44 and 45 (Broca’s area) of the left frontal lobe
