.RespiratorySystemConductingportion:Nasalcavityandoralcavity(forcedbreathing)Nasalcavity[Nares(Nostrils)---Vestibule(stratifiedsquamousepithelium,vibrissae)---Nasalfossae(respiratory&olfactorysegments/mucosae)---Choanae]---Nasopharynx,Oropharynx---Laryngopharynx(Hypopharynx)---Larynx---Trachea---PrimaryBronchi---Intrapulmonarybronchi---------Primarybronchioles---Terminalbronchioles---Respiratorybronchioles.

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RespiratoryportionRespiratorybronchioles(alveolialongthepassage)---Alveolarducts---Alveolarsacs---Alveoli.*Respiratorydiverticulumfromforegutevaginatesintothoracicmesenchyme.....PhysiologicalFunctions

1.Conditioningoftheair:warming,moistening,andremovalofdusts.2.Endocrinesecretion:Angiotensin-convertingEnzymefromalveolarendothelium.3.Immuneresponses:asthma..OlfactoryMucosa

Eepithelium(equivalenttoepidermisoftheskin):pseudostratifiedepithelium.2.Laminapropria(equivalenttodermis):directlycontiguouswiththeperiosteumofsurroundingbones;olfactory(Bowman’s)glands:serous..OlfactoryEpithelium:pseudostratifiedepitheliumOlfactorycells(bipolarsensoryneuronswitholfactoryciliathatcontainsodorant-bindingproteins/olfactoryreceptors,lifespan:1month)---olfactorynervefibers(axons)---olfactorynerveSupporting(sustentaclar)cells:glia-likecells,withmanymicrovilli.Basalcells:regenerative‘stem’cellsBrushcells:synapticcontactwithtrigeminalnerve;generalsensation......RespiratoryMucosa:nasalcavityEpithelium:pseudostratifiedepithelium;5celltypes:ciliatedcells,mucouscells,brushcells,smallgranulecellsandbasalcells.Laminapropria:directlycontiguouswiththeperiosteumofsurroundingbones;richinbloodsupplies..Paranasalsinuses:extensionsoftherespiratorysegmentofthenasalcavity;frontal,sphenoidal,ethmoidal,andmaxillarysinuses;respiratorymucosa..Pharynx

nasopharynx,oropharynxandlaryngopharynxLarynx

Phonation:glottis,includingrimaglottis(openingofthelarynx)andvocalfolds/cords(mucosa,ligament,andvocalismuscle);tensioninthevocalfolds(pitch;regulatedbyligamentsandintrinsiclaryngealmuscles);resonance(generatedbyventricles,ventricularfolds,nasalcavity,etc.)Deglutition(swallowing):larynxelevatedbyextrinsiclaryngealmuscles...OpenglottisVocalfoldsapartClosedglottisVocalfoldstogether...Thewallofthetrachea:respiratorymucosaMucosa:epithelium(pseudostratifiedepithelium),thickbasementmembrane(basallaminaandpackedcollagenousfibers),andlaminapropria(richinlymphatictissue).Submucosa:slightlydenserthanlaminapropria;richinlymphatictissue;submucosalglands;elasticmembranebetweenmucosaandsubmucosa.Cartilaginouslayer:Larynx(thyroid,etc.),trachea(C-shaped),primarybronchi(incompletering);intrapulmonarybronchi(plates).AdventitiaorSerosa

.....RespiratoryEpithelium:pseudostratifiedepitheliumCiliatedcells:“mucociliaryescalator”.Mucous(goblet)cells.Brushcells:withshort,bluntmicrovilli;maybesensorycells(epitheliodendriticsynapse).Smallgranulecells:withdense-corevesicles;cellsofdiffuseneuroendocrinesystem;catecholamineorpolypeptidehormones(serotonin,calcitonin,andgastrin-releasingpeptide/bombesin).Basalcells:regenerative‘stem’cells*Cysticfibrosis......BronchiMainbronchi(primary;extrapulmonary;L1,R1)---lobarbronchi(secondary;intrapulmonary;L2,R3)---segmentalbronchi(tertiary;L8,R10;bronchipulmonarysegment)Pulmonarylobule:consistsofabronchioleandtheareaitaerated.Pulmonaryacinus:consistsofaterminalbronchioleandtheareaitaerated.Respiratorybronchiolarunit:arespiratorybronchioleandtheareaitaerated.

*Thewallofthebronchus:mucosa,muscularis,submucosa,cartilagelayer,adventitia....BronchioleOnemmindiameter;withoutcartilagelayerandglands.Terminalbronchiole:withoutgobletcells;simplecuboidalepitheliumwithciliatedcellsandClaracells(secretasurface-activelipoproteinandClaracellproteinCC16),aswellasafewbrushandsmallgranulecells.......RespiratorybronchioleciliatedcellsandClaracells(majorcelltypeindistalend),aswellasfewbrushandsmallgranulecells;withalveoli(thesiteofgasexchange);withsmoothmusclelayer.Alveolarductlinedbyalveoli,withoutsmoothmusclelayer.Alveolarsac(space)

andalveoli........Alveolarepithelium:simplesquamousepitheliumtypeIalveolarcells:covers95%ofthealveolarsurface;thinsquamous;occludingjunctions;non-mitotic.typeIIalveolarcells:asnumerousastypeI;cuboidal;lamellarbodies(surfactant);progenitalcellsoftypeIalveolarcells.brushcells:fewinnumber........*Surfactant:modulatedbycortisol,insulin,prolactin,etc.

dipalmitoylphosphatidylcholine(DPPC):a

phospholipid,themajorsurfacetension-reducingagent;neonatalrespiratorydistresssyndrome(RDS).Hydrophobicproteins:SurfactantproteinA(SP-A):surfactanthomeostasis;immuneresponses.SurfactantproteinB(SP-B):surfactant-organizingprotein.SurfactantproteinC(SP-C):co-factorofSP-B.SurfactantproteinD(SP-D):bindsmicroorganismstolymphocytes..Interalveolarseptumalveolarepitheliumanditsbasallamina---laminapropria[capillaries(endothelialcellanditsbasallamina),fibroblasts,macrophages,mastcells,elasticfibers,andcollagenfibers,etc.]---alveolarepitheliumanditsbasallamina.

*Dustcells:alveolarmacrophages,inthe