BIOMED 4 Flashcards
The pharynx + tonsils + larynx + phonation
What is the length of the pharynx?
12-14cm long musculomembranous tube, extending between the nasal cavity & entrances to larynx and oesophagus
What is the shape of the pharynx?
Inverted cone
What does the pharynx play a role in?
Articulation + respiration
What are the 3 regions of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
What are the descriptive divisions of the pharynx?
Nasopharynx
-behind nose → soft palate
Oropharynx
-soft palate → tip of epiglottis
Laryngopharynx
-epiglottis → cricoid cartilage
What is the purpose of the nasopharynx?
Functional part of respiratory tract
What structures does the nasopharynx contain?
Pharyngeal tonsil (adenoids)
Opening of auditory tubes
Tubal tonsils
What is the auditory tube?
Connects middle ear to nasopharynx to equalise pressure either side of tympanic membrane
Drains middle ear
How does the oropharynx open into the mouth?
Oropharyngeal isthmus, demarcated by the palatoglossal arch
What does the lateral wall of the oropharynx consist of?
Palatopharyngeal arch
Palatine tonsil
Posteriorly, what is the oropharynx level with?
Bodies of 2nd and upper part of 3rd cervical vertebrae
Where does the laryngopharynx set behind?
Entire length of larynx, continuous with oesophagus
What lies in the upper part of the anterior wall of the laryngopharynx?
laryngeal inlet
Posteriorly, at rest, what is the laryngopharynx level with?
3rd to 6th cervical vertebrae
What happens to the laryngopharynx during swallowing?
Elevated considerably by hyoid elevators
What are the 2 muscles of the pharynx?
Circular (inner muscles)
Longitudinal (outer muscles
What do the circular muscles of the pharynx do?
Support peristalsis through constriction
What do the longitudinal muscles of the pharynx do?
Support peristalsis through elevation
What are the 3 pairs of pharyngeal constrictor muscles?
Superior constrictor
Medial constrictor
Inferior constrictor
+ cricopharyngeus (UES)
What is the function of the 3 pairs of pharyngeal constrictor muscles?
Act in sequence from top-bottom to propel bolus of food through pharynx
What do the 3 pairs of pharyngeal constrictor muscles look like?
Each pair meets in midline posteriorly
Vertically, they overlap so look like stacked plant pots
What are the 3 pairs of pharyngeal longitudinal muscles?
Stylopharyngeus (CN IX)
Palatopharyngeus (CN X)
Salpingopharyngeus (CN X)
What is the function of the 3 pairs of pharyngeal longitudinal muscles?
Elevate larynx + shorten and widen pharynx during swallowing
How is the pharynx innervated?
Fine network of nerves (plexus) running under the lining (sensory) & muscles (motor)
What is pharyngeal plexus formed from?
Pharyngeal branches of CNIX
Pharyngeal branches of CNX
Branches from external laryngeal nerve (branch of CNX)
Sympathetic fibres from superior cervical ganglion
Which cranial nerve does the pharynx receive sensory innervation from?
Glossopharyngeal (IX)
Which cranial nerve does the anterior & superior aspect of the nasopharynx receive sensory innervation from?
Trigeminal (V) branch 2 (maxillary nerve)
Which cranial nerve does the inferior aspect of the laryngopharynx receive sensory innervation from?
Superior laryngeal nerve (branch of vagus, CN X)
Which cranial nerves does the pharynx receive sensory innervation from?
All by vagus (CNX), except stylopharyngeus by glossopharyngeal (CNIX)
What does damage to the nerve supply of the pharynx cause?
Problems to swallowing (dysphagia)
What does damage to sensory supply (IX) cause?
Difficulty initiating + coordinating swallow
Gag reflex absent
What does damage to motor supply (X) cause?
Difficulty in smooth transit of material from mouth to oesophagus
What are tonsils?
Accumulations of lymphoid tissue
What is lymphoid tissues?
Protective to GI and respiratory tracts, as lymphocytes produce antibodies in response to bacteria + toxins
What happens to the tonsils if theirs an infection?
Enlarge
What are the 4 groups of tonsillar tissue?
Palatine tonsils (paired)
Pharyngeal tonsil (adenoids)
Lingual tonsils
Tubal tonsils (paired)
Where are the palatine tonsils situated?
Between palatoglossal arches + palatopharyngeal arches (oroharynx)
Where are the pharyngeal tonsils situated?
Posterior wall of nasopharynx
note: very variable in size
Where are the tubal tonsils tonsils situated?
Entrance to auditory tube
- may/may not be present, variable, small
Where are the lingual tonsils situated?
Under mucosa of posterior third of tongue
What is the tonsillar ring?
Waldeyers tonsillar ring: ring of defence for infections
What can chronic tonsillar enlargement interfere with?
Oral and nasal function
Why do enlarged tonsils in children cause a considerable blockage?
Tonsils twice the size of adult + tubes are smaller
What does enlargement of pharyngeal tonsil (adenoids) interfere with?
Soft palate elevation
Sinusitis, auditory tube dysfunction, middle ear infections, sleep apnea
Open mouth breathing, blocked nose breathing + hyponasality
Distort/prevent nasal speech sounds
What does enlargement of palatine tonsils interfere with?
Soft palate elevation
Hypernasality
What does enlargement of pharyngeal and tubular tonsil interfere with?
Auditory tube opening, middle ear infections, otitis media (glue ear)
What is tonsillectomy used for?
Chronic tonsillitis / complications
Sleep apnoea
What are tonsillectomies decreasing?
Important for fighting infection
What is the larynx a part of?
Part of the respiratory tract, reinforced by cartilage, cartilages articulate with each other at synovial joints, and can be moved with precision
What is the primary function of the larynx?
Protection of lower respiratory tract to prevent inhalation of food/liquids during swallowing / vomiting
What is the secondary function of the larynx?
Generation of noise by vibration of vocal folds (phonation)
What are the 4 key structures of the laryngeal skeleton?
Hyoid bone
Thyroid cartilage
Cricoid cartilage
Arytenoid cartilages + epiglottis
What is the difference between bone and cartilage?
Bone: harder, less elastic, has own blood supply
Cartilage: softer, elastic, gets nutrients via diffusion
What is the hyoid bone?
Bone at top of larynx, other parts suspended from there
How are the hyoid bone and thyroid cartilage joined?
By thyrohyoid membrane + thyrohyoid muscle
What is the epiglottis?
Leaf shaped cartilage which flaps over the opening of the larynx to protect the airway
How is the epiglottis connected to thyroid cartilage?
By thyroepiglottic ligament
What is the structure of thyroid cartilage?
Large lamina on both sides
Laryngeal prominence (adam’s apple)
Not a complete ring: open posteriorly
2 superior horns connects to hyoid
2 inferior horns connects to cricoid
At which joint does thyroid cartilage connect to cricoid? What does this mean?
Cricothyroid joint
Cricoid articulates (moves with) the thyroid cartilage (swings upwards to meet thyroid cartilage)
What is the shape of cricoid cartilage?
Signet: wider back, thinner front
Only complete ring of cartilage in respiratory system
What is the location of the arytenoids?
Sit on top of cricoid
What do the arytenoids form with the cricoid lamina?
2 synovial joints: the cricoarytenoid joints
Where do the vocal folds attach to the larynx?
Vocal processes of the arytenoids (posteriorly)
Thyroid cartilage (anteriorly)
What are the 3 movements possible at each cricoarytenoid joint?
Sliding
Rotation
Tilting
What are the sliding movements possible at each cricoarytenoid joint?
Slide medially (adduction): closes vocal folds
Slide laterally (abduction): opens vocal folds
What are the rotation movements possible at each cricoarytenoid joint?
Rotate inwards (adduction): closes vocal folds
Rotate outwards (abduction): opens vocal folds
What are the tilting movements possible at each cricoarytenoid joint?
Tilting backwards, increases length + tension, decreases thickness
Tilting forwards, decreases length + tension, increases thickness
What are 4 laryngeal muscles?
Cricothyroid muscle
Cricoarytenoids
Interarytenoids
Thyrpoarytenoid/vocalis muscle
What does the cricothyroid muscle do?
Pulls thyroid cartilage forward + down
Moves cricoid cartilage up, thus arytenoids move back
Stretches vocal cord to change thickness (high pitch)
How is the cricothyroid muscle innervated?
Superior laryngeal nerve of vagus
What are the 2 cricoarytenoids muscles?
Posterior
Lateral
(oppose one another)
Where is the posterior cricoarytenoid muscle?
From muscular process of arytenoid to posterior lamina of cricoid cartilage
What does the posterior cricoarytenoid muscle do?
Rotates arytenoids outwards to abduct vocal folds (opens rima glottis)
note: ONLY aBducters
Where is the lateral cricoarytenoid muscle?
From muscular process of arytenoid to superior/anterior areas of crcoid
What does the lateral cricoarytenoid muscle do?
Rotates arytenoids internally to adduct vocal folds (closes rima glottis)
What are the 2 interarytenoids muscles?
Lateral
Oblique
(may also connect to aryepiglottic muscle to support downward motion of epiglottis)
What do the interarytenoids do?
Connects arytenoids together
Contraction adducts vocal folds
What is the thyroarytenoid muscle?
Broad muscle that runs from the arytenoid to the thyroid cartilage (on the angle)
What does the thyroarytenoid muscle do?
Pulls artenoids close to thyroid cartilage
Makes vocal folds slacker/thicker/looser for low pitch
- broad adjustments
What is the vocalis muscle?
Inner portion of thyroarytenoid muscle
What does the vocalis muscle do?
Finer adjustments to thickness of vocal folds (pitch)
What are the vestibular folds?
False vocal folds
Superior to vocal folds
Different type of mucosa to vocal folds: respiratory epithelium
No role in phonation
What is the laryngeal mucosa?
larynx lined with respiratory epithelium
Except vocal folds, lined with stratified squamous epithelium
Which cranial nerve innervated the larynx?
Vagus (CNX)
- superior laryngeal nerve
- recurrent laryngeal nerve
What does the superior laryngeal nerve innervate?
Sensory to mucosa of larynx (internal branches)
Motor to cricothyroid muscles (external branches)
What does the recurrent laryngeal nerve innervate?
Motor to all laryngeal muscles (except cricothyroid)
What happens when the superior laryngeal nerve is damaged?
Loss of sensation to larynx: cough reflex/swallow initiation inoperative → aspiration
Loss of motor innervation to cricothyroid muscle → minor difficulty regulating pitch
How does damage to the recurrent laryngeal nerve/ nerve palsy (usually unilateral) occur?
90% due to bronchial carcinoma (cancer) in left lung
10% due to thyroid surgery
What happens when the recurrent laryngeal nerve is damaged?
All muscles on affected side paralysed…
not cricothyroid, vocal folds tensed as superior LN still achive
not interarytenoids (bilateral innervation), vocal folds partially adducted
→ harsh raspy voice
What is phonation?
Production of sound by modulating movement of air through vocal folds of larynx
What is phonation required for?
Vowels + voiced consonants, which make up around 2/3 of phonemes used in English
What are the 3 conditions for phonation?
- Flow of air from lungs
- Adduction of vocal folds (for subglottal pressure to build)
- Tension in vocal folds
If the 3 conditions for phonation are met, which theories explains why the vocal folds will vibrate?
Aerodynamic-Myoelastic Theory
Bernouli Effect
Explain the Aerodynamic Myoelastic Theory
Air comes up from lungs
Vocal folds adduct
Pressure builds below vocal cords (subglottal pressure) until it exceeds force of muscles tension used to adduct the folds
Air forces vocal folds open in explosive movement
Small amount of air rushes through narrow openingm, so subglottal pressure falls again
Explain the Bernoulli Effect
High velocity air/liquid causes low pressure
Objects pushed/pulled by pressure, so move accordingly
Rush of air that escapes moves at high velocity, causes low pressure so sucks vocal folds back in
What is the complex pattern of vocal fold movement?
Vocal folds open + close from bottom up
Vocal folds are mobile
Complex vibration along length
- fundamental frequency + formats
- valving of expiratory airflow by larynx is release of small puffs of air into vocal tract
What are the 2 muscles adducting vocal folds?
Interarytenoid muscles
:ateral cricoarytenoid muscles
note: controls subglottal pressure so affects intensity
What are the 3 variants in voicing?
Frequency
Intensity
Quality
What is voice frequency?
Number of vibrations/sec
Higher number of vibrations = higher pitch
How is voice frequency range determined?
Resting length + thickness of vocal folds
Longer resting length (not tense) = lower pitch
- males have thicker + shorter
What are the 3 physical parameters that determine higher pitch?
Increased…
Length: elongates ~20% of resting length
Thickness: mass/unit length, can change by factor of 2
Tension: stretch tighter/relax
note: all interrelated
Which muscles change the length + thickness of vocal folds?
Thyroartenoids (broad) shorten
Vocalis (fine) shorten + thickens
Cricothyroids used with these 2 to alter tension by contracting isometrically
What is voice intensity?
Perceived loudness
How does speech vary in intensity?
Normal speech varies over 30dB
Shout can read 70dB
What are the mechanisms that alter voice intensity?
Subglottal pressure: for each doubling = ~10dB intensity rise
- as pressure rises VFs blown apart with greater force, so open quicker
Vocal folds have to stay closed longer to dissipate force of closure, therefore results in air released at high pressure (think clapping!)
What additional muscles are used for high intensity by increasing tension in addition to force of adduction?
Circothyroid
Thyroarytenoid muscles
(isometric)
What is voice quality?
Recognising individual voices
Recognising changes in someone’s voice (eg: they have a cold)
note: any change to the parameters of phonation affects vocal quality
Clinical implications: What causes benign/malignant growth on the larynx?
Direct affect of disease
Manner of use
What is vocal misuse related to?
Occupation: noisy/requirement to raise voice
What does vocal misuse result in?
Increased loudness → strong adduction → trauma to contact points of vocal folds → bilateral vocal nodes/singer’s nodes (1/3 along length)
What does one’s voice sound like with vocal nodes?
Breathy/whispery
Hard to build up power
Which organic diseases result in voice changes?
Thyroid hormone deficiency
Osteoarthritis
How does thyroid hormone deficiency affect voice?
Fluid retention + oedema in whole body
Fluid build up in vocal folds causing thickening of vocal fold → pitch lowers
What does osteoarthritis affect?
Laryngeal joints, esp cricothyroid → affects pitch
How do neuromuscular disorders affect voice?
Muscular weakness/incoordination eg…
- stroke = weakness
- cerebellar ataxia = slurring
- Parkinson’s disease (smaller movements) = mono pitch / low pitch / quiet
How can drug medication affect voice?
Antidepressants/antipsychotics may affect neuromuscular control
Decongestants often produce ‘rebound effect’ when drug wears off, excess production of mucus from glands in respiratory tract, incl vestibular folds- vocal folds ‘thickened’
