BIOL164BIOL164

HumanBiologyHumanBiologyCh14RespiratorySystemCh14RespiratorySystem

TheRespiratorySystemTheRespiratorySystem

Generalfunc+ons:

1. SurfaceareaforexchangeofO2andCO2betweenairandblood

2. Breathing(pulmonaryven+la+on)

• movingairinandoutoflungs

3. Protec+onofrespiratorysurfaces

• E.g.fromdehydra+on,temperaturechanges,pathogens

4. Soundproduc+onforspeaking,etc.

5. Loca+onforsensa+onofsmell

OverviewofrespiratorysystemcomponentsOverviewofrespiratorysystemcomponents

PathwayofairthroughPathwayofairthroughrespiratorysystemrespiratorysystemduringbreathingduringbreathing

NoseandnasalcavityNoseandnasalcavity

• Nose=externalpor+on

• bone,car+lage,skin,muscle,mucousmembranes

• Nasalcavity=internalpor+on

• Mainfunc+ons:

• 1.Warmsandmoistensincomingair–duetorichbloodsupplyandlotsofmucusproduc+on

• 2.Filtersincomingair–hairs,mucus,andcilia(seenextslide)

• 3.Smell(olfac4on)–uppernasalcavityonly(detailsinCh.9)

• Nasalconchae(turbinates)–ridgesthats+rupair,increasesurfaceareaforwarming,moistening,filtra+ng,andsmelling

Nasalconchae

RespiratoryepitheliumRespiratoryepithelium• =pseudostra+fiedciliatedcolumnarepithelium(PSCC)

• Foundinnasalcavity,pharynx,larynx,trachea,bronchi

• Ciliamovemucusandpar+clestowardpharynxforswallowinganddestruc+oninstomach

• Calledthe“mucusescalator”inlowerrespiratorysystem

Pharynx(throat)Pharynx(throat)

• Passagewayforair,food,anddrink

• 3regions:

• 1.Nasopharynx(respiratoryonly)

• PCCE

• Containspharyngealtonsilandopeningsofauditory(Eustachian)tubes

• 2.Oropharynx(respiratoryanddiges+ve)

• Stra+fiedsquamousepithelium

• Containspala+neandlingualtonsils

• 3.Laryngopharynx(respiratoryanddiges+ve)

• Stra+fiedsquamousepithelium

Nasopharynx

Oropharynx

Laryngopharynx

Larynx(Larynx(““voiceboxvoicebox””))• Formedby9piecesofcar+lage(ligaments/musclestoo)

• Mainfunc+ons:

• 1.Allowair(butnotfood/drink)topassfrompharynxtotrachea

• EpigloKs=elas+ccar+lageplatethatclosesoffthegloKs(=superioropeningoflarynx)duringswallowing

• 2.Voiceproduc+onviathevocalcords(seenext2slides)

AnatomyofsoundproducMonAnatomyofsoundproducMon

PhysiologyofsoundproducMonPhysiologyofsoundproducMon• Voicepitch(frequency)–dependsontensiononandthicknessofvocal

folds

• ↑tension=↑pitch

• LaryngealmusclesaWachtoandadjusttensiononvocalfolds

• Thinnerfolds(females,prepubescentmales)=↑pitch

• Loudness(volume)–dependsonpressure/velocityofairrushingpastvocalfolds

• Whispering:notenoughairpressure/velocitytovibratevocal

cords,sonopitch

• Outgoingsound(voice)modifiedby:

• Musclesoftongue,face,lips

• Resona+ngchambers(pharynx,mouth,nasalcavity,paranasalsinuses)thataffecttone/+mbreofvoice

Trachea(Trachea(““windpipewindpipe””))

• =short(~5”)tubefromlarynxtojunc+onofprimarybronchi

• LinedbyPCCE

• Incomplete(C‐shaped)carMlagerings

• Preventcollapseduringinhala+on

• Allowexpansionofesophagusduringswallowing

• Trachealismuscle–smoothmuscleatthebackoftheringsthatadjustsdiameteroflumen(notshownbelow)

Trachea

CarMlagerings

BronchialtreeBronchialtree

• Func+on:rapidlyconductandspreadairfromeachbreathtorespiratoryexchangesurfaces(alveoli)

• Tracheadividesintotwoprimarybronchi(oneforeachlung)

• Bronchiaresupportedbycar+lageandhaveliWlesmoothmuscle

• Eachbronchusrepeatedlysubdividesintosecondarybronchi,terMarybronchi,etc.

• Eventually,thesmallestbranchesarecalledbronchioles

• Bronchioleshavenocar+lage,buthaveextensivesmoothmuscle

• Bronchiolesterminateinalveolarsacs(seenextslide)

LungsLungs• Eachsurroundedbyadouble‐

layeredsaccalledpleura

• Pleuralfluidisfoundbetween

thelayers

• Reducesfric+onbetween

layers

• Causeslayerstoadhere

tooneanother,

preven+ngcollapseof

lungs

• PleurafirmlyaWachesbaseofeach

lungtodiaphragm