Chapter 2: Anatomy and Physiology Flashcards
Where is the adult larynx located?
Opposite the 3rd, 4th, 5th, and 6th vertebrae (descends with age)
Where is the child larynx located
opposite ~4th vertebrae
What are the 4 parts of the laryngeal valve
cartilage, muscles, connective tissues, mucosa
What are the 3 main functions of the laryngeal valve?
1) airway preservation for ventilation 2) airway protection 3) phonation
What are the 3 levels of the vocal folds?
1) aryepiglottic folds 2) ventricular folds/vestibular folds 3) true vocal folds
Phonation relies on the power of what?
pulmonary respiratory power
What are the 4 aspects of what provides pulmonary respiratory power?
1) abdominal and thoracic musculature 2) lungs 3) diaphragm 4) pleural wall
What are the 5 muscles of inspiration?
1) diaphragm 2) external intercostals 3) sternocleidomastoids 4) scalenes 5) pectoralis (major and minor)
The diaphragm is _____-shape and does what upon inspiration?
dome; flattens
What do the external intercostals do when they contract?
Pull upward on the ribs they attatch to
What are the 5 muscles of expiration?
1) internal intercostals 2) rectus abdominis 3) transverse abdominus 4) internal obliques 5) external obliques
The muscles of expiration work in combination with what 3 things?
1) passive forces of torque 2) tissue elasticity 3) gravity
During speech, the expiratory muscles assist passive forces in order to do what things?
1) compress the abdominal viscera 2) force diaphragm upward and depress lower ribs 3) decrease thoracic cavity size (in order to sustain pulmonary pressure)
What are the 2 structural supports for the larynx?
1) hyoid bone
2) laryngeal cartilages
What are the 4 laryngeal cartilages?
1) epiglottis
2) thyroid
3) cricoid
4) arytenoids (corniculates and cuneiforms)
Where are the attachments for extrinsic laryngeal muscles?
One outside the larynx, one within the larynx
The extrinsic laryngeal muscles do what 3 things?
1) influence laryngeal height/position in neck
2) alter shape/filtering characteristics of supraglottic tract
3) modify vocal pitch, loudness, and quality
What are the 2 categories of laryngeal muscles?
1) suprahyoids
2) infrahyoids
What do the suprahyoids do?
raise the larynx
What are the 4-5 suprahyoids?
1) stylohyoid
2) mylohyoid
3) digastrics (anterior and posterior bellies)
4) geniohyoid
What do the infrahyoids do?
lower the hyoid and larynx
What are the 4 infrahyoids?
1) thyrohyoid
2) sternothyroid
3) sternohyoid
4) omohyoid
What do the intrinsic laryngeal muscles do?
affect the position, length, and tension of the vocal folds
What 3 things do the intrinsic laryngeal muscles do to change VF position, length, and tension?
1) change position of cartilage framework housing VFs
2) alter length, tension, and shape of the VF edge
3) change shape of glottal opening between VFs
What are the 5-6 intrinsic laryngeal muscles?
1) cricothyroid (CT)
2) thyroarytenoid (TA)
3) lateral cricoarytenoid (LCA)
4) interarytenoids (transverse and oblique)
5) posterior cricoarytenoid (PCA)
Which intrinsic laryngeal muscle is a tensor?
cricothyroid
What intrinsic laryngeal muscles are adductors?
1) thyroarytenoid
2) lateral cricoarytenoid
3) interarytenoids
What intrinsic laryngeal muscles are abductors?
posterior cricoarytenoid
Membranous portions of the VFs do what?
Oscillate (vibrate) to create sound
The integrity of the vibratory pattern for phonation requires what?
pliable, elastic structure
The adult VFs contain how many layers that vary in what 2 things?
5 discrete histological layers
composition and mechanical properties (giving different flexibility and stability)
What are the 5 layers of the vocal folds from superficial to deep?
1) epithelium
2) lamina propria (LP)
a) superficial (SLLP)
b) intermediate (ILLP)
c) deep (DLLP)
3) vocalis muscle (aka TA)
What increases when you progress from superficial to deep layers of the VF?
density and stiffness of tissue
The stiffness gradient of the VF layers is critical for what?
sustained vocal fold oscillation
Which VF layer is the outermost layer?
epithelium
Which VF layer can be described as mucosal, thin, and pliable?
epithelium
The epithelium is a thin layer of slippery mucous lubrication that is needed for what?
best VF oscillation
What covers the epithelium?
mucociliary blanket
What are the 2 layers of the mucociliary blanket?
1) mucinous
2) serous
What are 4 potential environmental influences that the epithelium can be exposed to?
1) humidity
2) dehydration
3) pollution
4) reflux
What is the basement membrane zone?
a transition zone between epithelium and lamina propria
What are the 3 layers of the lamina propria?
1) superficial layer
2) intermediate layer
3) deep layer
What are the 2 types of fibrous proteins (connective tissue) in the lamina propria?
1) elastin
2) collagen
What does elastin do?
allows tissue to deform/stretch
What does collagen do?
less stretchy than elastin, but tolerates stress and provides tensile strength
The lamina propria vibrates in a __________ manner in response to ________________ forces
passive
aerodynamic forces
The superficial layer is also called what?
Reinke’s space
Which layer of the LP is loose and flexible; soft, slippery, gelatin-like substance; and vibrates significantly during phonation?
superficial layer
Which layer of the LP has mostly elastic fibers and some collagen and also vibrates during phonation?
intermediate layer
Which layer of the LP is mostly collagen fibers and is interspersed with muscle fibers to join LP to underlying vocalis muscle?
deep layer
What are the intermediate and deep layers of the LP combined sometimes called?
vocal ligament
What does the vocalis muscle form?
body of the vocal fold
What 3 things does the vocalis muscle provide to the VF?
1) tone
2) stability
3) mass
Does the vocalis muscle oscillate during VF vibration?
Yes, but not as much as cover and transition layers of VF
What are the 3 divisions of the VFs?
1) cover = epithelium and SLLP
2) transition = ILLP and DLLP
3) body = vocalis muscle
What is one way to divide the VFs so there are 2 divisions of the VFs?
1) cover = epithelium, SLLP, ILLP (flexible)
2) body = DLLP and vocalis muscle (dense/stiff)
The predominant blood supply to the VFs are to what areas?
ILLP, DLLP, and vocalis muscle
Limited blood supply to the SLLP and epithelium gives us what?
a degree of protection from injury
What are the 3 parts of neurologic supply to the VFs?
1) CNS (sensory receptors and motor commands)
2) peripheral innervation
3) laryngeal reflexes
What CN is involved in the peripheral innervation of the VFs?
X - Vagus
What are the 2 parts of CNX involved in VF inneravation?
1) superior laryngeal nerve (SLN)
2) recurrent laryngeal nerve (RLN)
What are the two parts of the superior laryngeal nerve and what do they control?
1) internal - sensory for larynx above the VFs
2) external - motor principally the CT msucle
What is unique about the way the recurrent laryngeal nerve courses?
The left and right RLN paths are different
What does the recurrent laryngeal nerve provide motor innervation to?
all intrinsic laryngeal muscles except for the CT
What does the recurrent laryngeal nerve provide sensory innervation to?
below the vocal folds
What are the three theories of vibration?
1) Van den Berg’s Aerodynamic-Myoelastic Theory
2) Hirano’s Body-Cover Theory
3) Titze’s Self-Oscillation Theory
What does Van den Berg’s Aerodynamic-Myoelastic Theory say?
VF oscillation is a function of covarying pressure and flow as well as mechanical properties of tissue deformation and collision
What does Hirano’s Body-Cover Theory say?
Important role of the loose, passive (non-muscular) superficial layers (cover) to VF vibration as compared to the dense/stiff layers (body)
What does Titze’s Self-Oscillation Theory say?
The VFs are a flow-induced self-oscillating system, that are sustained across time by forces of pressure and flow; the convergent and divergent shaping of VFs in a back and forth motion creates an alternating exchange of airflow and pressure peaks
The VFs do NOT open and close during phonation due to what?
separate muscle contraction for each open/close movement
What is required for the VFs to open and close?
As long as VFs are in approximated position and have sufficient buildup of pressure below them
What is the fundamental frequency (Fo)?
rate of VF vibrations (cycles per second or Hertz)
The Fo is the acoustic-perceptual correlate of what?
pitch
What are 4 factors that influence Fo?
1) vocal fold length
2) longitudinal tension
3) vibratory amplitude
4) subglottal pressure
What is intensity?
Sound pressure level of acoustic output
What is intensity the perceptual correlate of?
loudness
What are the 4 factors that influence intensity?
1) subglottal pressure
2) vocal fold vibratory phase closure
3) transglottal flow
4) supraglottic vocal tract tuning
What are the 3 phonation modes?
1) falsetto/loft
2) modal/chest
3) glottal fry/pulse
What is the most important consideration in the pediatric population?
preservation of airway, the larynx/airway is most important system of the entire infant
In the pediatric larynx, what 2 structures are not as prominent as in an adult and which one of those is obscured by the overlapping hyoid bone
thyroid (obscured)
and cricoid
What 2 structures of the larynx are large relative to other structures?
1) aryepiglottic folds
2) arytenoid cartilages
What is the estimated percent of infants with an omega shaped epiglottis?
50%
What is the length of VF in newborns?
1.25-3.0mm
When does difference in VF length with gender begin to occur?
around 10
What is the adult male and female VF lenghts?
Male = 17-21mm Female = 11-15mm
