Respiratory System Flashcards
What are the two general portions of the respiratory system?
Conducting and Respiratory Portion
Name the components of the conducting portion of the respiratory system in the order air passes them
Nose, nasopharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles
What alternative purposes does the conducting system serve?
Warms, moistens, and filters air
What are the three segments of the nasal cavity?
Respiratory segment (nares), olfactory segment, vestibule
What is the epithelial lining of the vestibule? Hint - there are two types
Changes from nonkeratinized strat. squam. epithelium to pseudostratified ciliated columnar epithelium posteriorly
What are vibrissae and what do they do?
Vibrissae are short hair that filter out particles in the vestibule
What are the specialized cells/glands of the olfactory epithelium?
Olfactory cells, supporting (sustenacular) cells, Bowman’s glands
Explain the action of olfactory cells and Bowman glands to create the sense of smell
Bowman’s glands secrete watery secretion via ducts that fixes odorous chemicals onto surface, olfactory cells detect and as bipolar nerves, conduct nerve impulse
What are important distinguishing structural features of Olfactory cells, supporting cells, and basal cells?
Olfactory cells have modified cillia (proximal 1/3 has 9 doublet + 2 config and distal 2/3 has 9 SINGLET + 2 config).
Supporting cells have apically located nuclei and terminal webs.
Basal cells do not extend to the surface and serve as stem cells
How do Bowman’s cells affect olfactory cilia in terms of new odorous stimulus?
Secretion flushes receptors to receive new stimuli.
When does the nasopharynx become the oropharynx?
At the soft palate
What is the epithelial lining of the nasopharynx?
Respiratory epithelium (cilliated psuedostratified columnar epithelium)
What is respiratory epithelium?
Cilliated pseudostratified columnar epithelium
Does the Nasopharynx contain glands? What tissue is especially abundant in this area?
Contains mucous and serous glands in lamina propria. Has a ton of lymphoid tissue like nasopharyngeal tonsils
What does the larynx connect?
The pharynx and the trachea
What are the three structures of hyaline cartilages in the larynx? What structures are made of elastic cartilage?
Thyroid, crycoid, and lower part of arytenoid are hyaline. Epiglottis, corniculate, and tips of arytenoids are elastic.
What kind of muscle is within the laryngeal walls?
Striated muscle
What is the epithelium of the vocal cords?
Stratified squamous nonkeratinized epithelium
What are vestibular folds?
Folds of loose connective tissue superior to the vocal cords containing glands, lymphoid aggregations, and fat cells.
What is the epithelium of vestibular folds
Stratified squamous nonkeratinized epithelium (like the rest of the vocal cord type things)
What conducting structure is supported by C-shaped hyaline cartilages with open ends facing posteriorly and smooth muscle extending between open ends?
The trachea
What is in between the adjacent C-rings of the trachea?
Dense fibroelastic cartilage
What are the layers of the trachea from most superficial (anterior) to most deep (posterior and internal)?
Adventitia, cartilage, submucosa, mucosa (epithelium and lamina propria)
Is the internal elastic membrane well defined or poorly defined in the trachea?
Poorly defined
What happens during bronchitis to the submucosal layer?
Bronchitis results in a proliferation of the submucosal layer
What kind(s) of cells are present in the epithelium of the trachea?
Respiratory epithelium, mucus cells, brush cells, small granule cells, and basal cells
What is a brush cell?
Columnar cell with blunt microvilli that may be in contact with afferent nerve ending and functions as a receptor cell
What kind of granules does a small granule cell contain?
What diffuse system does it participate in?
What is another name for the cells?
Catecholamines and other polypeptide hormones.
Part of the diffuse endocrine system.
bronchial cells of Kulchitsky
What is the function of the basal cell in both the trachea and the nasopharynx?
Stem cells for regeneration of epithelium
What is the difference between the trachea and bronchi in terms of structure?
Bronchi have cartilage rings and spiral bands of smooth muscle that completely encircle the bronchi, where as trachea is only partially encircled by each with the cartilage dispersed as irregular cartilage plates
What is unique about the smooth muscle fibers in the bronchioles?
Arranged in spiraling smooth muscle bundles which separate the lamina propria from the submucosa
What are the layers of the bronchi from innermost to outermost?
Mucosa (epithelium and basal lamina), muscularis ( smooth muscle layer), submucosa, cartilage layer, adventitia
What are some primary indicators that you have transitioned from bronchus to a bronchiole?
No glands in the submucosa, walls have smooth muscle without cartilatge plates, begin to see Clara cells in smaller passages
What is the epithelium transition in the bronchioles?
Cilliated columnar with goblet cells to cilliated columnar with clara cells
What distinguishes a terminal bronchiole in terms of epithelium
Epithelium becomes simple cuboidal, mostly clara cells, some respiratory epithelium, no goblet cells
What are the distinguishing features of clara cells?
Cuboidal cells, dome shaped apical surface, no cilia.
Cells can divide
Secrete glycosaminoglycans to protect the bronchiolar lining
Metabolize airborn toxins - contain cytochrome P450 in smooth ER
Structures in the respiratory portion of the airway
Respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
What is a respiratory bronchiole? What is its epithelium contents? How could you recognize it in a slide?
Respiratory bronchiole is the patheway to alveoli and alveolar ducts.
It has a simple cuboidal lining with clara cells, but some ciliated cells are still present proximally. Occasionally bbbrush and dense-core granule cells but rare.
Bronchiole walls are visibly interrupted by alveolar ducts
What is the difference between a respiratory bronchiole and an alveolar duct in terms of function?
Respiratory duct conducts from terminal bronchiole to branching alveolar ducts with minimum alveoli on the walls, alveolar ducts conduct to alveoli.
(I know this is a lame question, point is though that you need to be able to recognize the difference between a respiratory bronchiole and an alveolar duct cuz they look pretty similar)
What is the epithelial lining of the alveolar duct? Does it contain smooth mucle?
Simple squamous epithelium with type I and ype II pneumocytes, yes contains smooth muscle at openings of alveoli and most dista portion of respiratory system to do so
What is the difference between an alveolar sac and an alveoli?
Alveolar sacs are outpuchings of numerous alveoli at the distal end of the alveolar duct
What portions of the respiratory system are alveoli present?
Respiratory bronchiole walls, alveolar ducts, alveolar sacs
Where are alveolar pores located? What are they for?
Located in interalveolar septa, for pressure equalization and for passage of prostacylins
What is present in the openings vs the walls of the alveoli?
Openings have elastic fibers and walls have reticular fibers
What is the epithelium of the alveoli?
Type I and type II pneumocytes
What is the purpose of the alveoli?
O2 and CO2 diffuseion between air and blood
How prolific are Type I pneumocytes?
How are Type I pneumocytes connected?
What would happen if there was a problem with occludin or claudin in terms of pneumocyte function?
95% of alveolar surface
Tight junctions
They would allow in toxins or other undesirables
What is the purpose of type II cells? What are their other names? Where are they found?
Type II cells store pulmonary surfactant and serve as regenerating stem cells for both type I and II as they can divide unlike type I.
ALso named great alveolar cells, granular pneumocytes, and septal cells
Usually found near septal intersections
What does the interalveolar septum contain?
Continous capillaries, elastic and reticular fibers, simple squamous apithelium.
What is the blood -gas barrier? What would gas have to permeate to move from the alveoli to the blood in terms of layers?
Passage gas passes to reach alveoli to blood. First pass through Type I pneumocyte and surfactant layer, then fused basal lamina of pneumocytes and capillary endothelial cells, then the endothelium of continuous capillaries.
What are the four proteins present in pulmonary surfactant? What isthe name of the phospholipid?
SP-A, SP-B, SP-C, SP-D. Dipalmitoyl-phospholipidcholine (DPPC)
What is surfactant released by in Type II pneumocytes and what is an example of what it can produce?
Released by lamellar body secretary granules and can form tubular myelinn (NOT MYELIN OR RELATED TO NERVOUS SYSTEM).
70-85% of the cells in the airways of the alveoli are ______
Alveolar macrophages (a.k.a. dust cells)
What can result in an increase in number and activation of macrophages?
Inflammatory conditions
DDX: Labored breathing due to difficulty expanding the alveli, improves with glucocorticoids
Hyaline membrane disease - premature infants lack adequate amounts of pulmonary surfactants made by Type II cells
How would you treat Neonatal respiratory distress syndrome?
Same as Hyaline membrane disease - administer glucocorticoids
DDX: destruction of bronchioles and alveolar ducts, found alpha1-antitrypsin deficiency. Formation of cyst like sacks. Barrel chested
alpha1-antitrypsin deficiency induced emphysema
How does emphysema kill you?
Reduced lung elasticity means lungs can’t recoil, reduced gas exchange surface area
What does alpha1-antitrypsin do?
Protects elastase in lungs from neutrophils.
What are reasons for emphysema?
Hereditary, defective alpha1-antitrypsin in liver, possibility for gene therapy.
Smoking or substances that inhibit a1-antitrypsin
What are two possible causes of pulmonary edema?
Cardiogenic - left ventricle dysfunction leads to dilation of pulmonary capillaries, increase in hydrostatic pressure, potential rupture of fluid into interstitial tissue and alveoli
Endotoxin or other agent (like water near drowning or chemicals) results in destruction of endothelial lining and results in leak
What is asthma fundamentally?
Constriction of bronchiolar smooth muscle
DDX: Difficult air expiration, mucus accumulation, heightened inflammatory cell infiltration, potentially allergic reactions
Asthma
How to treat severe asthma?
Epinephrine and isoproterenol or other smooth muscle relaxants
What does an allergen cause?
Mast cell degranulation, release of histamine, etc.
Why does cystic fibrosis result in extremely thick mucus?
Defective ion channel prevents chloride movement, chloride accumulation leads to sodium influx to balance charge, water follows sodium and dehydrates mucus
What are two disorders of the pleura?
Hydrothorax (fluid in pleural cavity), pneumothorax (air in pleural cavity)
What dysfunctions in cystic fibrosis?
CTFR - ion channel dysfunction
