Histology for PathologyRespiratory System Theresa Kristopaitis, MDAssociate ProfessorDirector of Mechanisms of Human DiseaseKelli A. Hutchens, MD, FCAPAssistant ProfessorAssistant Director of Mechanisms of Human DiseaseLoyola Stritch School of Medicine!"ecti#es$n %eneral terms descri!e the function of the conductin% portion of the respiratory systemList the components of the conductin% portion of the respiratory system$n %eneral terms descri!e the function of the respiratory portion of the respiratory systemList the components of the respiratory portion of the respiratory system&'plain the function of (mucous) and list the cell type *hich produces it$dentify hyaline cartila%e in a histolo%ic section and descri!e its primary role in the respiratory system&'plain the +ey features of (respiratory epithelium)n a histolo%ic section distin%uish the trachea #s !ronchus #s !ronchioleList the cell types found in an al#eolusn a histolo%ic section identify the al#eolar septa, capillary, endothelial cell, and pneumocyte $dentify macropha%es in a section of lun% tissue and descri!e their functionDescri!e the path of an o'y%en molecule from the trachea throu%h the conductin% portion of the air*ay into a capillary in the *all of an al#eolusConductin% Portion Upper Airway: bone, cartilage, and fbrous tissue lined by stratifed squamous and ciliated pseudostratifed columnar epithelia ,asal Ca#ity Pharyn' ,asopharyn' ropharyn' Laryn' &pi%lottis- elastic cartila%e .ocal cords- striated s+eletal muscle / elastic 0!ers Lower Airway: lined by respiratory epithelium Trachea- C1shaped cartila%e *ith smooth muscle 2ronchi &'trapulmonary / primary !ronchi- !e%in at the !ifurcation of trachea and lead to lun%s- e'tensions of the trachea $ntrapulmonary/secondary and tertiary !ronchi- !e%in at lun% hilum.Smooth muscle and hyaline cartila%e plates 2ronchioles- no cartila%e and Clara cells Terminal !ronchioles- increased Clara cells Functions- Transports 3arms Humidi0es FiltersConductin% portion- Lo*er Air*ayTrachea- connects laryn' to primary !ronchiMucosa- respiratory epithelium 4 ciliated pseudostrati0ed columnar epithelium and lamina propria Ciliated cells, %o!let cells, !asal cells, and neuroendocrine cellsSu!mucosa- dense connecti#e tissue and seromucous %lands Hyaline cartila%e- C1shaped5 some smooth muscle 6trachealis7 to sta!ili8e openin%Ad#entitia- connecti#e tissue that co#ers cartila%eTracheaMucosaSu!mucosaHyaline Cartila%eAd#entitiaTrachea 9 :espiratory &pithelium;o!let CellsCiliaMain / Primary 2ronchi 6e'trapulmonary !ronchi7Similar structure to trachea :i%ht is *ider and more #ertical than the leftConductin% portion- Lo*er Air*aySecondary /Tertiary 6$ntrapulmonary 7 2ronchiMucosa- respiratory epithelium as seen in trachea and primary !ronchi Smooth muscle !and !et*een su!mucosa and mucosa$nner#ated !y the sympathetic and parasympathetic systemsSu!mucosa-seromucous %landsHyaline cartila%e platesAd#entitia Conductin% portion- Lo*er Air*ay2ronchus, secondaryHyaline Cartila%e PlatesSmooth muscle !andConductin% portion- 2ronchioles Mucosa-lined !y respiratory epithelium *ith Clara cells replacin% %o!let cellsDome shaped cells *ithout cilia secrete %lycosamino%lycans and secretory proteins Clara cells increase as !ronchioles %i#e rise to terminal !ronchioles &pithelium %radually !ecome mostly clara cells *ith cu!oidal rather than ciliated epithelium as the terminal !ronchioles near the respiratory !ronchiolesSmooth muscle layer,o cartila%eAd#entitia Clara Cell&lectron micro%raph 6&M7 of the respiratory mucosa.,>>>,>>> ' thus it is #ery useful to loo+ at the ultrastructural characteristics of a cell. 2ronchioleTerminal !ronchiole:espiratory portionFunction- ;as &'chan%e:espiratory !ronchioles- tu!es !et*een al#eoliAl#eolar ducts/al#eolar sacs- arise from respiratory !ronchioles !ut ha#e more al#eoli and terminate as !lind pouchesAl#eoli- Thin1*alled pouches lined !y type $ / type $$ pneumocytes:espiratory Portion- :espiratory 2ronchiolesTertiary !ronchioles %i#e rise to respiratory !ronchiolesFirst air*ays to function in %as e'chan%eLined !y cu!oidal cells and connect to al#eoli and al#eolar ducts ! 4 respiratory !ronchiole *ith al#eolus 6a7 in its *all. Most of the *all of the !ronchiole has a de0nite line of dar+ alon% it, si%nifyin% a cu!oidal epitheliumd ? c 4 al#eolar duct. $ts *all consists almost entirely of al#eoli, *hich ha#e only a simple s@uamous linin%, too Aat to !e #isi!le here. e 4 al#eoli 6the smallest respiratory units7 f 4 !lood #essel 6!ranch of pulmonary artery still7:espiratory !ronchioles, al#eolar ducts, and al#eoliDucts are lined !y s@uamous al#eolar cells 6type $ pneumocytes7 *ith +no!s of cu!oidal cells&ach duct functions as a corridor to connect se#eral al#eoliAl#eoliBCD1BED Type $ pneumocytes- Aat dar+ o#al nucleus and thin cytoplasm Small percenta%e of Type $$ pneumocytes- can di#ide and replace type $ cells 9 lar%e poly%onal cells at corner of al#eoli. Secrete components of pulmonary surfactant.Lined !y septa 4 !lood1air !arrier for case e'chan%e formed !y delicate connecti#e tissue and capillariesAl#eolar macropha%es- a+a dust cells, located in septa, often contain pha%ocyti8ed material:espiratory Portion- Al#eolar ducts and al#eoliAl#eolar Macropha%es Al#eolar spaces 1 SeptaType $ PneumocytesType $$ Pneumocyte$llustrati#e &M&M sho*in% !asal lamina 6=7 !et*een s@uamous al#eolar epithelium 6F 4 Type $ cell7 and capillary endothelium 6G7. The nucleus at upper ri%ht !elon%s to the endothelial cell linin% the capillary. The dar+ structure is a red !lood cell. The capillary plus the al#eolar linin%s on !oth sides constitute the inter al#eolar septum that lies !et*een t*o al#eolar spaces.