Respiratory Quiz #1 Flashcards
Identify clinical significance of the dimensions of the trachea and bronchi.
Tracheal dimensions- 11-13 cm long
Right Mainstem Bronchus
>1-2.5 cm from carina
>25 degrees off trachea
>1.6 cm width
Left Mainstem Bronchus
>5 cm from carina
>45 degrees off trachea
>1.3 cm width
List 3 factors affecting upper airway tone
- Upper airway muscles can be affected by anesthesia and decreasing airway diameter
- Sleep? Causing sleep apnea!?
- muscles of pharynx and larynx control upper airway resistance
- muscles can be affected by anesthesia
- larynx has poor lymphatic drainage and is prone to edema
Identify the three areas from teeth to bronchi with the smallest cross-sectional area.
- Incisors
- Oropharynx
- Glottis
Describe the innervation of the tongue.
Glossopharyngeal(CN#9) innervates posterior 1/3
Trigeminal/Lingual(CN#5) innervates the anterior 2/3
- Lingual (part of CN V) = anterior 2/3 of tongue
- Glossopharyngeal (CN IX) = posterior 1/3 of tongue
Describe the anatomy of the laryngeal cavity and vocal cords.
- Larynx extends from epiglottis to cricoid
- Inlet of larynx formed by upper border epiglottis cartilage, aryepiglottic folds and arytenoid cartilage
- Inside the laryngeal cavity are the vestibular folds (false cords); just lateral to the true vocal cords
- True vocal cords = attach anteriorly to thyroid and posteriorly to the arytenoids
- Larynx has poor lymphatic drainage → prone to edema
- Triangular fissure is the glottic opening between vocal cords
Identify which laryngeal muscles abduct, adduct and regulate tension of the vocal cords.
Posterior cycoarytenoids-abduct
Lateroal crycoarytenoids-adduct
Cyricothyroid/Thyroarytenoid-Regulators of tension
Identify the most narrow portion of the lower airway in adults.
Glottis is the narrowest part of the lower airway in adults
Discuss the effects of recurrent laryngeal and superior laryngeal nerve damage.
- RECURRENT LARYNGEAL NERVE:
- SENSATION BELOW VOCAL CORDS - DAMAGE MAY CAUSE VOCAL CORD PALSY (INTERMEDIATE POSITION BETWEEN ABDUCTED AND ADDUCTED); “CAN’T TAKE A VERY DEEP BREATH”
- May occur from radial neck dissection, parotidectomy, redo thyroidectomy (distorted tissues); no NMB so nerve can be identified by Bovie with “NIMS” ETT, blue part goes in between vocal cords
- Right RLN damage– partial abduction, smaller flow
- Bilateral RLN damage– can’t talk, large problem with flow; have patient phonate “e” to rule out b/c that requires both vocal cords
- SUPERIOR LARYNGEAL NERVE:
- Sensation about the VC and to the cricothyroid
- STIMULATION MAY PROVOKE LARYNGOSPASM/FLACCID CORDS
Describe the mucosa of the nasopharynx and trachea.
- Nasopharynx mucosa =
- Goblet cells: secrete 100 ml/day of mucous, aids in trapping inspired particles and prevents them from entering lungs
- Columnar cells: Contain 200-250 cilia, beat in waves toward oropharynx (mouth), at a rate of 2 cm/min; propels towards mouth so it can go into esophagus versus lungs
- Trachea mucosa=
- Pseudostratified columnar epithelium with cilia; goblet cells, serous cells, and specialized submucosal bronchial glands
- 200+ cilia per cell, 5-7 microns long
- Beat cephalad (head) direction toward oropharynx at 2 cm/minute; “keeps you from having an obstruction” in lungs
- Functions to humidify air and removes particles (cilia)
- All of these specialized cells can be interfered with
Discuss the intrathoracic section of the trachea and its significance.
- Top half of trachea is extrathoracic, bottom half intrathoracic
- Extrathoraic is “not prone to things like PEEP but its prone to atmospheric limitation you can compress it (such as choking)”
List four factors which slow mucociliary transport
- Cigarette smoke
- Dehydration
- Positive pressure ventilation
- Endotracheal suctioning? “May or may not”
- High inspired oxygen concentrations? “May or may not”
- Hypoxia
- Atmospheric pollutants
- General anesthesia
- Parasympatholytic drugs (glycopyrrolate); can also increase your dead space while trying to clear secretions
Describe the anatomy of the trachea and main bronchi and clinical implications
trachea 11-13 cm long
RMS bronchus 1-2.5 cm long and wider than LMS bronchus; at a 25’ angle off trachea
aspirated objects generally go into the RMS bronchus > than the LMS bronchus
Compare and contrast the conducting and respiratory zones of the tracheobronchial tree.
Generations 0-14 Conducting zone: no exchange here; anatomic deadspace 150ml (apart of TV/minute ventilation, but no gas exchange) • Trachea • left and right mainstem bronchi • Lobar bronchi • Segmental bronchi • Terminal bronchioles Generations 15-23 Respiratory zone: gas exchange occurs here (such large quantity you have a large surface area for gas exchange even though a smaller number of generations) • Respiratory bronchioles • Alveolar ducts and alveolar sacs
Compare and contrast epithelium and cartilage in different generations of the lung.
GENERATION 0-1(TRACHEA AND MAIN BRONCHUS) HAVE COLUMNAR EPITHELIUM AND U-SHAPED CARTILAGE
GENERERATION 2-11 HAVE COLUMNAR CILIATED EPITHELIUM AND IRREGULARLY SHAPED CARTILAGE
GENERATION 12-23 HAVE NO CARTILAGE AND HAVE HAVE CUBOIDAL CELLS THAT MAKE UP THE EPITHELIUM AND ARE BETWEEN THE ALVEOLI
- Epithelium of respiratory tract: Pseudostratified (ciliated), Columnar (ciliated), Cuboidal in terminal bronchioles (no cilia)- by then the particles have to be tiny to get down there anyways so no cilia is needed
- Pseudostratified columnar ciliated epithelium from nasal cavity to bronchioles
- Cuboidal epithelium from bronchioles to alveolus
- Goblet cells produce mucous that lines all airways (increased in asthma and cystic fibrosis)
- Mucous is propelled forward by ciliated epithelial cells
- Other cells found in the respiratory epithelium include basal cells, mast cells, nonciliated bronchiolar epithelial cells and APUD cells
- Basal cells-Absent in bronchioles and beyond, they are stem cells responsible for producing new epithelial and goblet cells
- Mast cells-Activation is the main cause of immediate bronchospasm seen in allergen-induced asthma
- Non-ciliated bronchiolar (Clara) cells-Involved in the metabolism of chemical toxins
-Smooth muscle in respiratory tract: Increases as airway gets smaller; it depends on traction from lung itself and having air left in bronchioles to keep the airways open, so its important to have some residual volume (closing volume) left to prevent collapse
-Cartilage
Trachea:
-Adventitia (outermost connective tissue) made up of hyaline cartilage
-Cartilage anteriorly, muscle dorsally/posteriorly (sharing area with esophagus, so if you fill esophagus too much with food its compresses trachea b/c there isn’t hard cartilage there)
-Supported by “U” or “C” shaped cartilages (16-20 in number) joined posteriorly by smooth muscle bands to keep it from collapsing, then incomplete plates (incomplete rings), then eventually complete rings further down
-External pressure of 40 cmH2O is sufficient to compress the trachea at extrathoracic portion
Bronchi:
-“Right and left main bronchus still have a good amount of cartilage b/c they are large and compressible by the pressure in the chest”
-3rd generation its replaced by elastic fibers (in VOPPT says “small amounts of cartilage persist irregularly all the way down to the bronchioles”, but later in slides says there is no cartilage here)
List three functions of the respiratory epithelium.
- Humidification (heat and moisture exchange)
- Chemical barrier and particle clearance
- Defense against infection
Identify the type of epithelium in generations 1-11, 12-18, and 19-23.
- Generations 1-11: Columnar ciliated epithelium
- Generations 12-18: Cuboidal/ 15-18 are cuboidal b/t alveoli
- Generations 19-23: Cuboidal between alveoli
Identify which bronchus generations have cartilaginous support.
- Generations 1-2 have U shaped cartilage
- Generations 2-11 have irregular shaped cartilage
- Generations 12-23 have no cartilage present
Identify the cells responsible for bronchospasm in asthmatics
Mast cells
Identify the mechanism responsible for maintaining potency of generations 5-11.
- 5-11 patency relies partially on some cartilage in walls and also positive transmural pressure gradient,
- Needs pressure gradient btw pleural space and airway or airway can collapse
- So pleural space pressure can’t be higher than airway pressure
- “Not enough smooth muscle or air in bronchi to keep them open and not enough cartilage to keep them open”
- These generations constrict and cause air trapping in asthmatics and COPD
Identify the generation of bronchioles where the transition from conduction to respiration occurs
-Generation 15-18 is where transition from conduction to gas exchange occurs
Describe the approximate number of alveoli
-About 200-800 million (mean 300 million), depending on height
Describe the amount of surface area available for gas exchange.
- 50-100 m-squared (about the size of a tennis court) for gas exchange
- Size of alveoli is proportional to lung volume
- Larger in upper part of lung d/t gravitational weight of lung, but vertical size gradient disappears at maximal inflation
- Mean diameter is 0.2mm at FRC (volume that’s left in lungs before with take a breath)
Define pores of Kohn and their significance
- Small fenestrations in the alveolar septa (adjoining walls of alveoli) that provide collateral ventilation between alveoli
- Allow for passage of gas from an open alveoli to a closed alveoli, so you reduce the amount of V:Q mismatch
- Between 3-13 micrometers in diameter
- Formation is due to: desquamation d/t to disease, normal degeneration d/t aging, or movement of macrophages leaving holes
Differentiate between the active side and service side of the alveolar septum.
- Active Side: capillary endothelium and alveolar endothelium are close, such that the total distance from gas to blood is 0.3 micrometers, where gas exchange is more efficient
- Service Side: usually more than 1-2 micrometers thick; sizeable interstitial space containing elastin, collagen, nerve endings and macrophages; more affected by edema and fibrous tissue; “can accumulate a lot of fluid on this side before it starts to affect the active side where gas exchange occurs”
Differentiate between Type I and Type II alveolar cells.
- Type I epithelial alveolar cells:
- Thin, allow macrophages and albumin to pass between their junctions
- 95% of the alveolar surface
- Made up of squamous pneumocyte cells
- Between 0.1-0.5 micrometers thick
- Major site of gas exchange
- Type II epithelial alveolar cells:
- Stem cells from which Type 1 cells arise
- Involved in pulmonary defense and secrete cytokines (responsible for inflammation)
- Produce and store pulmonary surfactant, primary source
- Only 5% of surface of alveoli
- Composed of granular pneumocyte cells
- Cuboidal in shape with microvilli
- Involved with reabsorption of fluids in the dry, alveolar spaces
Discuss the primary function of surfactant.
- Acts as a detergent to decrease surface tension;
- Pulmonary compliance is increased and work of breathing is reduced
- Permits alveolar stability by keeping smaller alveoli from collapsing into larger alveoli (the smaller they are the more they want to collapse on themselves without surfactant)
Identify three factors affecting gas diffusion at the alveolar-capillary interface.
- According to Fick, factors affecting diffusion include:
1. Gas concentration gradient
2. Membrane area (OLV, lobectomy)
3. Membrane thickness
List four functions of the lungs.
- Allow oxygen and carbon dioxide exchange
- Maintain/regulate pH
- Metabolizes/synthesizes/converts compounds (fentanyl and heparin)
- Filters unwanted materials from the circulation
- Acts as a reservoir for blood (amt. of blood in lungs 4-20%)
- Defense against environment (nose and cilia in bronchi)
Describe the difference between the parietal pleura and visceral pleura and their function
- Parietal pleura lines thoracic wall
- Visceral pleura covers the lung surface
- Pleural cavity is space between the two layers
- Pleural fluid fills the space; can get a pleural effusion here
Compare the role of the sympathetic and parasympathetic nervous system in regulating bronchial tone.
- Parasympathetic motor fibers (predominate)
- Constrict the bronchi
- Affected by medication, mechanical (minimal effect)
- Sympathetic (weak)
- Dilate the bronchi
- Affected by medication, agents (good impact- albuterol)
- Our drugs seem to work better on sympathetic receptors than parasympathetic
Identify the most important muscle in respiration and its innervation.
- Diaphragm (75% of inspiration occurs here)
- Innervated by phrenic nerve (C3-C5)
- Considerable functional reserve (1-7cm)
Describe the function of the lymphatic system in the lungs.
- Lymphatic vessels remove fluids and protein molecules that leak out of the pulmonary capillaries
- Transfer fluids back into the circulatory system
- Nodes acts as filters to keep particles and bacteria from entering the blood
- Pathology can lead to edema
List three metabolic functions of the lungs.
- Conversion of angiotensin I to angiotensin II
- Complete or partial inactivation of vasoactive substances (bradykinin, serotonin, prostaglandins)
- Metabolism of several vasoactive and bronchoactive compounds such as arachidonic acid metabolites (leukotrienes, prostaglandins, prostacyclin)
- Major role in clotting mechanism (mast cells contain heparin) and immune system (IgA production)
Describe the role of the respiratory system in acid-base balance.
- Increases in carbon dioxide lead to increases in hydrogen ion concentration (H+) as: -CO2 + H2O H2CO3 H+ + HCO3-
- Respiratory system thus participates in acid-base balance by removing CO2 from the body
- CNS has sensors for the CO2 and H+ levels in the arterial blood and CSF which determine minute ventilation
The orifice of the right main stem bronchus is how far from the carina?
1 - 2.5 cm
Which of the airwayy channel has the smallest dimension?
glottis
What nerve provides sensory innervation to the posterior 1/3 of the tongue?
glossopharyngeal
What muscles abducts the vocal cords?
posterior crycoartenoids
During DL for intubation, you notice the left vocal cord is in an intermediate position what do you suspect?
recurrent laryngeal nerve damage
What type of epithelial cells make up the tracheal mucosa?
Pseudostratified Ciliated Columnar
What are 3 things that may slow mucociliary transport?
cigarette smoke volatile agent parasympatholytic drugs(robinol)
Compared to the conducting zone of the lungs, the respiratory zone has more?
alveoli
_____ epithelium are NOT found in the respiratory bronchioles, alveolar ducts and the alveoli?
Ciliated columnar celss
What cells are responsible for bronchospasm in asthmatics?
mast cells
Potency of the airways in generations 5-11(small bronchi) are dependent upon what?
partially on transmural pressure gradient
