Lecture 1: Anatomy Of Respiratory System Flashcards
What are 8 anatomical structures of the respiratory system?
- Nose/mouth
- Pharynx
- Larynx
- Trachea
- Bronchi
- Terminal bronchi
- Lungs and alveoli
- Pulmonary vessels
What are 6 anatomical structures of the nose?
- Nare
- Meati
- Conchae
- Sinuses
- Septum
- Palate
What are 3 functions of the nose?
- Warm inhaled air to body temperature (done by the conchae and septum)
- Filter and obstruct foreign particles (via nasal hair/cilia)
- Assists in phonation and sensation of smell (CN I)
What is the anatomical structure of the pharynx?
- Posterior oral structure
- Connects the nose, mouth, larynx, and middle ear
What are the tonsils?
-Muscular mucosal lymph tissues
What are the 4 functions of the pharynx/tonsils?
- Assists in phonation (forming speech)
- Initiates deglutition (swallowing)
- Defense against infectious pathogens
- Enlarges with inflammation and tumor
What are the 5 parts of the ring of tonsils?
AKA Waldeyer’s Ring
- Adenoid
- Eustachian
- Palatine
- Lingual
- Sublingual
How do we perform airway evaluation according to Mallampati classification?
- Pt sitting with…
- neck extended
- mouth opened fully
- tongue protruded
- no phonation
MP Class 1
-Full view of uvula and tonsillar pillars, soft palate
MP Class 2
-Partial view of uvula or uvular base, partial view of tonsils, soft palate
MP Class 3
-Visualization of soft palate only
MP Class 4
-Visualization of hard palate only
Glossoptosis
-Collapse of oropharynx, tongue dropping posteriorly
Macroglossia
-Large tongue
Micrognathia
-Small jaw, mandible
Prognathism
-Protruding jaw, mandible
Microgenia
-Small chin
Microstomia
-Small mouth
Malocclusion
-Upper protrusion, “buck teeth,” overbite
What is the anatomical location of the larynx?
- Adults: located anterior to C3-C6 vertebrae
- At birth: C3-C4
- Located between pharynx and trachea
- A-O extension: normally 35 degrees
What are the 5 main functions of the larynx?
- Functions as the airway protective sphincter
- Closes off airway during swallowing
- Supports vocal cords
- Modulates speech
- Provides auto PEEP
What are the 3 compartments of the larynx?
- Supraglottis compartment
- Glottis (ventricle)
- Infraglottis compartment
What is in the supraglottis compartment?
- Epiglottis
- False vocal cords
What is in the glottis (ventricle)?
- True vocal cords
- Rima glottidis–in adults, the narrowest portion of the upper airway
- Arytenoids
What is in the Infraglottis compartment?
- Below the vocal cords
- Cricoid cartilage
- Trachea
What are the 9 structures in the larynx (cartilaginous skeleton)?
- 3 unpaired:
- epiglottis
- thyroid
- cricoid
- 3 paired:
- Arytenoid
- corniculate
- cuneiform
What does the hyoid bone do?
-Suspends the larynx
What are the two types of muscles in the larynx?
- Extrinsic muscles
- Intrinsic muscles
What are two functions of the extrinsic muscles of the larynx?
- Attach the larynx to bone or the pharynx
- Move the larynx during swallowing
What are the functions of the intrinsic larynx muscle sets?
- There are two sets of intrinsic larynx muscles–each set performs a different function:
- One set alters the size and shape of the larynx
- Other set of muscles move the true vocal cords
What are the 3 specific intrinsic muscles that alter the size and shape of the larynx, and what are they Innervated by?
- Aryepiglottic
- Thyroepiglottic
- Oblique Arytenoid
- Innervated by the recurrent laryngeal nerve
Aryepiglottic-function and innervation
- Pulls epiglottis down over larynx
- Innervated by the recurrent laryngeal nerve
Thyroepiglottic-function/innervation
- Assists pulling epiglottis down
- Innervated by the recurrent laryngeal nerve
Oblique Arytenoid-function/innervation
- Pulls arytenoids together, adductor
- Innervated by the recurrent laryngeal nerve
What are the 6 intrinsic muscles that move the true vocal cords?
- Cricothyroid
- Thyroarytenoid
- Lateral Cricoarytenoid
- Posterior Cricoarytenoid
- Traverse Arytenoid
- Vocalis
Cricothyroid-function/innervation
- Tensor of the vocal cords
- Innervated by the external superior laryngeal nerve
Thyroarytenoid-function/innervation
- Relaxor of the vocal cords
- Innervated by the recurrent laryngeal nerve
Lateral Cricoarytenoid-function/innervation
- adductor
- Innervated by the recurrent laryngeal nerve
Posterior Cricoarytenoid-function/innervation
- Abductor
- Innervated by the recurrent laryngeal nerve
Traverse Arytenoid-function/innervation
- Adductor
- Innervated by the recurrent laryngeal nerve
Vocalis-function/innervation
- Abductor (weak)
- Innervated by the recurrent laryngeal nerve
-How does the larynx move during swallowing?
- Upward
- Hyoid bone elevates the larynx, suprahyoid bone indirectly moves the larynx
What 5 muscles directly attach to the larynx?
- Thyrohyoid
- Salpingopharyngeus
- Stylopharyngeus
- Inferior constrictor
- Palatopharyngeus
What are three important membranes of the larynx?
- Thyrohyoid membrane
- Quadrangular membrane
- Cricothyroid membrane
What is the Quadrangular membrane?
- Epiglottis to Arytenoid
- Lateral wall of larynx
What is the Cricothyroid membrane?
- Inferior to the true vocal cords
- Emergency airway–cricothyroidotomy or jet ventilation***
What does the recurrent laryngeal nerve do?
- Part of the vagus nerve branch (CN X)
- Left recurrent laryngeal nerve passes at the aortic arch
- Provides sensory innervation to the infraglottis
- Provides motor innervation to all of the larynx except for the Cricothyroid muscle
The left recurrent laryngeal nerve passes at the ___
-Aortic arch
The recurrent laryngeal nerve provides sensory innervation to ___
-the infraglottis
The recurrent laryngeal nerve provides motor innervation to ___
-All of the larynx except the Cricothyroid muscle
Stimulation of the recurrent laryngeal nerve causes…
-abduction (move apart, opening) of the vocal cords
Damage of the recurrent laryngeal nerve causes…
-vocal cord adduction (come together, close)
What is the superior laryngeal nerve?
- Part of the vagus nerve (CN X) branch
- Divides into two nerves: internal superior laryngeal nerve; external superior laryngeal nerve
What does the INTERNAL superior laryngeal nerve do?
- Provides sensation to the supraglottic and ventricle compartment
- Stimulation of the internal SLN causes LARYNGOSPASM***
What does the EXTERNAL SLN do?
-Provides motor innervation of the Cricothyroid muscle
What does the sphenopalatine ganglion innervate?
- Part of the middle division of CN V (trigeminal nerve)
- Innervates nasal mucosa, superior pharynx, uvula, tonsils
What does the glossopharyngeal nerve (CN IX) innervate?
- back 1/3 of the tongue
- oral pharynx
- tonsillar nerves
- supraglottic region
What does the internal branch of the SLN (CN X–vagus nerve) innervate?
- mucus membrane above the vocal cords
- glottis
What does the recurrent laryngeal nerve (CN X–vagus nerve) innervate?
-trachea below the vocal cords
What is the epiglottis?
- Flap-like structure
- Positioned upright to allow air passage during inspiration
What is the vallecula?
-Space anterior to the epiglottis at the root of the tongue
What does pressure on the hyoepiglottic ligament do?
-Lifts the epiglottis during laryngoscopy
What is the epiglottis position during swallowing?
- Epiglottis covers glottis to protect airway
- Larynx raised upward by muscular contractions
- Epiglottis is pressed downward by base of tongue
What are the vocal folds (glottis)?
- Two pairs of horizontal membrane folds:
- False vocal cords
- True vocal cords
What are the false vocal cords?
- Upper vestibular folds
- Close during swallowing
What are the true vocal cords?
- Responsible for vocal sounds
- Mobile elastic fibers
- Vocal ligament within
What is the mucous membrane of the vocal folds?
- Loosely attached, except at the vocal cords
- Susceptible to edema***
What are the grades of view via direct laryngoscopy (DL)?
-Grades 1-4
Grade 1 DL
-full view of vocal cords, glottis
Grade 2 DL
-partial view of vocal cords, Arytenoid, and corniculate cartilages
Grade 3 DL
-only epiglottis visualized
Grade 4 DL
-only soft palate visualized
Abduction of vocal cords
- Abduction = move apart, open
- Passive resting position
- Vocal cords abduct during inspiration
What is the only abductor muscle of the vocal cords?
-Posterior Cricoarytenoid = only abductor muscle
Stimulation of what nerve abducts (or opens) the vocal folds?
-Stimulation of the recurrent laryngeal nerve
Adduction of the vocal cords
- Adduction = move together, close
- Intrinsic muscles close and tense the vocal folds
What two nerves are responsible for adduction (closure) of the vocal folds?
- Recurrent laryngeal nerve responsible for adduction of vocal folds
- Superior laryngeal nerve tenses the vocal folds via the Cricothyroid muscle
How is sound produced via the vocal cords?
- Air is forced between CLOSED cords, which causes vibration
- Vibratory sound waves are formed into words by upper airway movement
What upper airway structures are involved in sound modification?
- Pharynx/oral cavity
- Tongue/lips
How is pitch controlled by the vocal cords?
- Control of vocal cord tension…
- Increased tension = higher-pitched sound
- Decreased tension = lower tone
How is intensity of sound controlled by the vocal cords?
- Loudness is related to the force of air passing between the vocal cords
- Stronger blasts of air cause vocal cords to vibrate more and produce louder sounds
What is the cricoid ring?
-A complete ring of cartilage shaped like a signet ring
What is the cricoid?
- Cricoid is a cartilage ring located below the larynx and thyroid cartilage (Adam’s apple)
- Found between the Cricothyroid membrane and trachea
What is Sellick’s maneuver and when is it used?
- Pressure on the cricoid applied posteriorly to close the esophagus
- Prevents gastric regurgitation into the trachea, used during…
- rapid sequence intubation, trauma, full stomach, GERD, obesity, pregnancy, gastroparesis, SBO, pyloric stenosis, etc.
- Aligns glottic opening during intubation
- Prevents air into the stomach
Cricoid in children
- The cricoid is the narrowest part of the upper airway in children
- It is cone shaped, narrowing inferiorly
- Until age 8 years
What is the trachea?
- Flexible cylindrical tube supported by 20-25 C-shaped cartilages
- 18-20 mm diameter
- 12.5-18 cm length
- Extends from C6-T5
Where does the trachea divide?
- At the carina–level T5-T7
- Divides into 2 bronchi
- @ 25 cm from teeth
What prevents tracheal collapse?
-Incomplete C-shaped cartilage–there is connective tissue/smooth muscle posteriorly
What is trachealis?
- Posterior smooth muscle of the trachea
- Allows for esophageal expansion
What filters air that enters the trachea?
-Ciliated epithelium filters air and conducts particles upward to pharynx on mucus carpet
What is the bronchial tree?
- Branched conducting airways
- Multiple divisions into smaller, shorter tubes
What are functions of the bronchial tree?
- Distributes air to alveoli
- Warms and humidifies air
- Filters and transports particles from lungs, ciliated
What is special about the right primary bronchus?
-It is slightly straighter and wider
What happens to airway diameter/area with branching?
- Airway diameter decreases with branching
- Overall cross-sectional area increases, so resistance decreases tremendously
Conducting airways do not participate in…
- Gas exchange–ventilation occurs, but no perfusion
- Portion of each breath is wasted ventilation–30% of each normal breath remains in airway (150 ml/700 ml breath)
What is acinus?
- Includes all respiratory structures–respiratory bronchiole, alveolar ducts/sacs, alveoli
- Site of gas exchange
Where does the conducting airway end?
-It ends at the respiratory bronchiole
What are the alveolar sacs/alveoli?
- Terminal respiratory unit
- Simple diffusion allows gaseous exchange between airspace and pulmonary capillaries
- Multiple cell types present in alveolar wall
The lower respiratory tract is lined by…
-mucosa and contain variable amounts of muscle and/or cartilage
Airways become progressively…
-smaller and increasingly involved in gas exchange
Pseudostratified ciliated columnar epithelium (PS-CC)
- PSCC found from larynx to bronchi
- Cilia remove trapped particles
- Disabled by smoke
What are goblet cells?
- GC release mucous granules into airway lumen
- Creates mucous blanket that moistens inspired air, prevents drying of airway, and traps particles
- GC increase with injury and infection
Clara cells
- Located in smaller bronchiole which lack goblet cells
- Produce mucus-poor, watery, proteinaceous material
- This secretion combines with surfactant and mucus to assist cleaning small airways and reduce surface tension in bronchioles
What are 6 cell types found in the alveolar wall?
- Type I pneumocyte
- Type II pneumocyte
- Endothelial capillaries
- Macrophages
- Septal cells (fibroblasts)
- Mast cells
Type I pneumocyte
- Covers 95% of alveolar wall
- Squamous epithelial cell
- Flat thin cells designed to increase alveolar surface area
- Thin surface facilitates gas exchange
- Less than 0.2 micrometers thick
Functions of type I pneumocyte
- Controls fluid movement between interstitium and airspace
- Susceptible to injury and unable to regenerate self
- Held together by tight junctions
- Simple diffusion
Type II pneumocyte
- Cuboidal
- Capable of mitosis
- Repairs alveolar epithelium after injury
- PC II regenerate PC I
- PC II secretes surfactant
- Maturation of PC II occurs at 24 weeks gestation***
What is surfactant and what does it do?
- Surface-active material
- Mix of proteins, phospholipids, and ions
- Mixes with water molecules and decreases the cohesiveness, thus diminishing the surface tension of alveolar fluid, which reduces the force necessary to inflate the alveoli and facilitates breathing
- Prevents alveolar collapse during expiration, important in neonate
Macrophages
-Found throughout interstitium and alveolar spaces
Septal cells
- AKA fibroblasts
- Maintain connective tissue of lung
Mast cells
-produce histamine
