lect resp4d

8/10/2019 Lect Resp4d

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RESPIRATORY SYSTEMRESPIRATORY SYSTEM

Histology lectureHistology lecture bbyy

Doc. MUDr.Doc. MUDr. DimitrolosDimitrolos KrajKraj,, CScCSc

Department of Histology & EmbryologyDepartment of Histology & Embryology

Faculty of Medicine,Faculty of Medicine, PalackPalackUniversity,University,

Olomouc, CZOlomouc, CZ

10/2009


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R E S P I R A T O R Y S Y S T E MR E S P I R A T O R Y S Y S T E M

It is composed ofIt is composed of2 principal regionsprincipal regions ::

11-- CONDUCTING PORTIONCONDUCTING PORTION

FunctionFunction:: Conducting, conditioningConducting, conditioning

((ccleansing, moistening, warming,)leansing, moistening, warming,)

and sampling (smelling) of airand sampling (smelling) of air

to breath.to breath.

22-- RESPIRATORY PORTIONRESPIRATORY PORTIONFunctionFunction:: Exchange ofExchange of

respiratory gases (Orespiratory gases (O22, CO, CO22))

from the air to blood.from the air to blood.[5]

LUNGS

NASAL,L

ARYNX,TRACHEA,BRO

NCHI


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THE WALLTHE WALLIN RESPIRATORY AIRWAYSIN RESPIRATORY AIRWAYS

A ]A ] Tunica MUCOSATunica MUCOSA-- composed ofcomposed of

a)a)Respiratory lining epitheliumRespiratory lining epithelium

pseudostratified columnarpseudostratified columnar

ciliated.ciliated.

bb)) Lamina propriaLamina propria --composed ofcomposed ofaa loose connective.loose connective.

B]B] TelaTela SUBMUCOSASUBMUCOSA composedcomposed

ofof cconnective tissue joiningonnective tissue joining

the mucosa, may be absent orthe mucosa, may be absent or

may be supported withmay be supported with ccartilageartilage

oror bbone.one.

C]C] Tunica ADVENTITIATunica ADVENTITIA

(May be absent in certain regions.)(May be absent in certain regions.)7Wall of a large bronchus, Tol.blue stain, LM x 250


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A ]A ] Tunica MUCOSATunica MUCOSA

It isIt is composedcomposed of :of :

a)a)Respiratory lining epitheliumRespiratory lining epithelium --

PSEUDOSTRATIFIED COLUMNARPSEUDOSTRATIFIED COLUMNAR

CILIATED EPCILIATED EPITHELIUMITHELIUM whichwhich

consists ofconsists of 6typestypesof cells :of cells :11 -- Columnar ciliated cellsColumnar ciliated cells --

Each cell possesses aboutEach cell possesses about 300 cilia300 cilia

on its apical surfaceon its apical surface ++basalbasal bodies.bodies.

((FFunctionunction: Transport of the mucus: Transport of the mucus

with entrapped dust partwith entrapped dust particlesicles..))

NumerousNumerous mitochondriamitochondriaare locatedare located

in the subsurface zone of thein the subsurface zone of the

apicalapical cytoplasm (sourcecytoplasm (source ofof ATP).ATP).11


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[7]

Apical part of ciliated respiratory

epithelial cells, EM x 9000

A ] Tunica MUCOSAA ] Tunica MUCOSA

[8]Pseudostrat. col. ciliated epithelium, H&E stain, LM x 540


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[7]7Surface of ciliated epithelial cells, SEM x 2500Surface of ciliated epithelial cells, SEM x 2500Apical part of ciliated respiratory

epithelial cells, EM x 9000

MucociliaryMucociliary flowflow
http://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Cilia%20greyscale.flvhttp://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Cilia%20greyscale.flvhttp://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Cilia%20greyscale.flvhttp://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Cilia%20greyscale.flv


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(( 6 types of cells6 types of cells -- cont.)cont.)

22 -- Goblet cellsGoblet cells -- single cellsingle cell

mucous glands containingmucous glands containing

mucous droplets (polysaccharidemucous droplets (polysaccharide

rich products, PAS +).rich products, PAS +).33 -- Intermediate cellsIntermediate cells-- are growingare growing

cells transforming into ciliatedcells transforming into ciliated

or goblet cells.or goblet cells.

44 -- Basal cellsBasal cells-- are short cells restingare short cells resting

on basal lamina but not extendedon basal lamina but not extended

to the lumen they areto the lumen they are reregenerativegenerative

cells undergoing mitoses.cells undergoing mitoses.[11]


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22 -- Goblet cellsGoblet cells -- single cellsingle cell

mucous glands containingmucous glands containing

mucous droplets (polysaccharidemucous droplets (polysaccharide

rich products, PAS +).rich products, PAS +).

33 -- Intermediate cellsIntermediate cells-- are growingare growing

cells transforming into ciliatedcells transforming into ciliated

or goblet cells.or goblet cells.

44 -- Basal cellsBasal cells-- are short cells restingare short cells resting

on basal lamina but not extendedon basal lamina but not extended

to the lumen they areto the lumen they are reregenerativegenerative

cells undergoing mitoses.cells undergoing mitoses.

[7]Goblet cells in respiratory ep.,

Tol.blue stain, LM x 350


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55 -- Brush cellsBrush cells-- columnar cells withcolumnar cells with

numerous apicalnumerous apical microvillimicrovilliandand

afferent nerve endings on theirafferent nerve endings on their

basal surfacesbasal surfaces (sensory receptor(sensory receptor cells).cells).

66 -- Small granule cellsSmall granule cells-- similar tosimilar to

basal cells but with numerousbasal cells but with numerous

densedense--cored granulescored granules (diam.100(diam.100 --

200 nm) in their cytoplasm.200 nm) in their cytoplasm. They belong to the diffuseThey belong to the diffuse

neuroendocrineneuroendocrine systemsystem

(integration of the mucous and(integration of the mucous and

serous secretory processes).serous secretory processes). [11]


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bb)) Lamina propriaLamina propria :: Is composed ofIs composed of aa loose connectiveloose connective

tissue with some elastic fibtissue with some elastic fibers,ers,

Mixed (seromucous)Mixed (seromucous) glandsglandsareare

frequently located here.frequently located here. Blood and lymphaticBlood and lymphatic vesselsvesselsandand

nerves are in the c. t.nerves are in the c. t.

Bundles ofBundles of smooth musclesmooth muscle maymay

be present in this layer.be present in this layer. Lymphoid nodulesLymphoid nodules ((MALTMALT== MMucosaucosa

AAssociatedssociated LLymphoidymphoid TTissue)issue)..

This layer may be continuous withThis layer may be continuous with

periosteum or perichondrium.periosteum or perichondrium.[8]Nasal cavity, intraepithelial gland, H&E, LM x 540

LP


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B]B] TelaTela SUBMUCOSASUBMUCOSA

It is composed of connectiveIt is composed of connectivetissue joining the mucosatissue joining the mucosa

with underlying structures.with underlying structures.

It may containIt may contain cartilagenouscartilagenous

segmentssegmentsandand smooth musclesmooth muscle(tunica fibro(tunica fibro--musculomusculo--cartilaginea).cartilaginea).

C] Tunica ADVENTITIA] Tunica ADVENTITIA(if present)(if present)

Is composed of a looseIs composed of a loose

connective tissue withconnective tissue with

blood vessels, peripheral nervesblood vessels, peripheral nerves

and lobules of adipose tissue.and lobules of adipose tissue.[8]Layers of the wall of trachea, H&E, LM x 200

LP

TS

TA


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NASAL CAVITYNASAL CAVITY

[A][A] VESTIBULEVESTIBULE

[B][B] NASAL FOSSAENASAL FOSSAE

Respiratory regionRespiratory regionOlfactory regionOlfactory region

[C][C] PARANASALPARANASAL

SINUSESSINUSES

[D][D] NASOPHARYNXNASOPHARYNX

[3]


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[A][A] VESTIBULEVESTIBULE of the nasal cavityof the nasal cavity

Lined byLined by stratified squamousstratified squamousepitheliumepithelium(thinly keratinized)(thinly keratinized)

Sebaceous glands and sweat glandsSebaceous glands and sweat glands

are in the lamina propria.are in the lamina propria.

Thick short hairsThick short hairs VIBRISSAEVIBRISSAE

are there to filter the air.are there to filter the air.

[11]


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Composed ofComposed of: +: + Nasal CavitiesNasal Cavities++ Nasal SeptumNasal Septum

++ 3 Nasal Conchae3 Nasal Conchae-- sup., middle, inf.sup., middle, inf.

Two regions:Two regions:

1 Respiratory regionespiratory region :

Middle and inferior conchae areMiddle and inferior conchae are

covered by respir. lining epith.covered by respir. lining epith.

Lamina propria containsLamina propria contains

VENOUS PLEXUSESVENOUS PLEXUSES (swell bodies)(swell bodies)causing distention of conchalcausing distention of conchal

mucosa and decrease of airmucosa and decrease of air

flow velocity to warm up the airflow velocity to warm up the air

passing by.passing by.

x


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Respiratoryespiratory

mucosaucosa :

Lamina propriaLamina propria

containscontains

VENOUS PLEXUSESVENOUS PLEXUSES(swell bodies)(swell bodies)

causing distentioncausing distention

of conchalof conchal

mucosa andmucosa anddecrease of airdecrease of air

flow velocity toflow velocity to

warm up the airwarm up the air

passing by.passing by. [11]


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Respiratory

and olfactory

mucosa,

Human, H&E,

LM x 270 [dk]OlfactoryOlfactorymucosamucosaOlfactoryOlfactorymucosamucosa

Respiratory mucosaRespiratory mucosaRespiratory mucosaRespiratory mucosa


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2 Olfactory regionlfactory region:

Superior concha is coveredSuperior concha is covered

byby OLFACTORY EPITHELIUMOLFACTORY EPITHELIUM

which is awhich is a modifiedmodified

pseudostratified columnarpseudostratified columnar

(non(non--ciliated) epith.ciliated) epith. withoutwithout

goblet cells.goblet cells.

Lamina propria containsLamina propria contains

tuboalveolar (seromucous)tuboalveolar (seromucous)

BOWMANS GLANDSBOWMANS GLANDS andand

abundant blood vesselsabundant blood vessels

and nerves (fila olfactoria).and nerves (fila olfactoria).[3]


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Olfactorylfactory

mucosa:ucosa:

OLFACTORYOLFACTORY

EPITHELIUMEPITHELIUMLamina propriaLamina propria

contains tuboalveolarcontains tuboalveolar

(seromucous)(seromucous)

BOWMANSBOWMANSGLANDSGLANDS andand

abundant bloodabundant blood

vessels and nervesvessels and nerves

(fila olfactoria).(fila olfactoria).[11]


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OLFACTORY EPITHELIUMOLFACTORY EPITHELIUM

It is composed of :It is composed of : Supporting cellsSupporting cells-- tall columnartall columnar

cells with microvilli.cells with microvilli.

Basal cellsBasal cells-- conical cells atconical cells at

the basal lamina.the basal lamina.

Olfactory cellsOlfactory cells-- bipolar neuronsbipolar neurons

with narrow apex and nonmotilewith narrow apex and nonmotile

cilia (9 +1 double microtubules).cilia (9 +1 double microtubules).

Afferent axons of these neuronsAfferent axons of these neurons

are directed toward CNSare directed toward CNS

(olfactory bulb).(olfactory bulb).

Fila olfactoriaFila olfactoria==unmyelinated ax.unmyelinated ax. [11]


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OLFACTORY EPITHELIUMOLFACTORY EPITHELIUM

BRAINBRAIN

[16]NASAL CAVITYNASAL CAVITY


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OLFACTORYOLFACTORY

EPITHELIUM (function)EPITHELIUM (function)

[1]


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[C][C] PARANASAL SINUSESPARANASAL SINUSES

FRONTAL, MAXILLARY, ETHMOID AND SPHENOID SINUSESFRONTAL, MAXILLARY, ETHMOID AND SPHENOID SINUSES are:are:

Lined with a thinner respiratory ciliated epithelium with a few goblet cells.Lined with a thinner respiratory ciliated epithelium with a few goblet cells.

Mucus drains into the nasal passages.Mucus drains into the nasal passages.

Lamina propria is continuous with periosteum of surrounding bones andLamina propria is continuous with periosteum of surrounding bones and

contains only a few glands.contains only a few glands.

[D][D] NASOPHARYNXASOPHARYNX

Is lined with respiratory typeIs lined with respiratory type

of epithelium.of epithelium.

There is aThere is a nasopharyngealnasopharyngeal

tonsiltonsil (adenoid) located(adenoid) located

in mucosa of the pharyngealin mucosa of the pharyngeal

fornix.fornix. x


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L A R Y N XL A R Y N X

It is a tube that connects the pharynx withIt is a tube that connects the pharynx with

the trachea, its functions are:the trachea, its functions are:

a) To createa) To create soundssoundsfor vocation.for vocation.

b) To prevent inspired airb) To prevent inspired air

enteringentering esophagus.esophagus.

c) To prevent ingested food andc) To prevent ingested food and

liquids entering theliquids entering the trachea.trachea.

It is composed of:It is composed of:

EPIGLOTTISEPIGLOTTIS andand

LARYNX PROPERLARYNX PROPER

5


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EPIGLOTTISEPIGLOTTIS

Has two surfaces:Has two surfaces:

11 -- Linqual surfaceLinqual surface -- coveredcoveredwithwith

stratified squamous noncornifiedstratified squamous noncornified

epithelium (oral).epithelium (oral).

22 -- Laryngeal surfaceLaryngeal surface -- coveredcoveredwithwith

pseudostratified columnar ciliatedpseudostratified columnar ciliated

epithelium (respiratory).epithelium (respiratory).

+ Supporting+ Supporting elasticelastic cartilage..cartilage..

+ Mixed glands.+ Mixed glands.

3

Larynx, vocal cords, laryngoscopic view


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EPIGLOTTISEPIGLOTTIS

1

Epiglottis, elastic cartilage, elastin stain, LM x 132Epiglottis, elastic cartilage, elastin stain, LM x 132

8

8 Detail of elastic cartilage, elastin stain, LM x 540Detail of elastic cartilage, elastin stain, LM x 540


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Parts of the larynxParts of the larynx::

Vestibule.Vestibule.

False vocal cordsFalse vocal cords

(vestibular folds).(vestibular folds).

Laringeal ventricle.Laringeal ventricle. True vocal cordsTrue vocal cords

(vocal folds).(vocal folds).

StructureStructure::11-- MUCOSAMUCOSA:: Lined mostly withLined mostly with


epithelium with goblet cellsepithelium with goblet cells

(except for true vocal cords!).(except for true vocal cords!). 11


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StructureStructure:: (cont.)(cont.)

22-- LAMINA PROPRIALAMINA PROPRIA:: containscontains

Loose connective tissue withLoose connective tissue with

Mixed glands andMixed glands and

Laryngeal cartilages:Laryngeal cartilages: thyroidthyroid,,cricoidcricoid,,arytenoidarytenoid

cartilcartil. are. are hyalinehyaline cartilages,cartilages,

epiglottis, cuneiform,epiglottis, cuneiform,

corniculatecorniculateandand tips oftips of

arytenoidarytenoidareare elasticelastic cartilagescartilages

Binding ligamentsBinding ligaments

Intrinsic muscles of the larynx.Intrinsic muscles of the larynx.(striated muscle)(striated muscle)

11


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FALSE VOCAL CORDS :FALSE VOCAL CORDS :

(vestibular folds)(vestibular folds)

Are covered by respiratory liningAre covered by respiratory lining

epithelium (pseudostratifiedepithelium (pseudostratifiedcolumnar ciliated).columnar ciliated).

SeroSero--mucous glands in the laminamucous glands in the lamina

propria.propria.

Fibrocollagenous stroma withFibrocollagenous stroma withlymphatic nodules.lymphatic nodules.

Ventricular recessVentricular recess invaginatesinvaginates

between the false and true vocalbetween the false and true vocal

folds.folds.11


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TRUE VOCAL CORDS :TRUE VOCAL CORDS :

Are covered by stratifiedAre covered by stratified

squamoussquamous uncornifieduncornified epithelium.epithelium.

Bundles of elastic fibers in laminaBundles of elastic fibers in laminapropriapropria ( VOCAL LIGAMENT ).( VOCAL LIGAMENT ).

Skeletal muscleSkeletal muscle ( VOCALIS( VOCALIS

MUSCLE ).MUSCLE ).

10Larynx, frontal section, LM x 10


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Human larynx, frontal section, H&E, LM x 14 8Vocal cords in actionVocal cords in action
http://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Laryngoscopy%20-%20Vocal%20Cords%20in%20Action.flvhttp://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Laryngoscopy%20-%20Vocal%20Cords%20in%20Action.flvhttp://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Laryngoscopy%20-%20Vocal%20Cords%20in%20Action.flv


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T R A C H E AT R A C H E A

Is a thinIs a thin--walled rigid tubewalled rigid tube

(10 cm long x 2.3 cm in diam.)(10 cm long x 2.3 cm in diam.)

extending from the base of larynxextending from the base of larynx

to the bifurcation into twoto the bifurcation into two

primary bronchi.primary bronchi.

Its wall is has the following layers:Its wall is has the following layers:

A] T. MUCOSAA] T. MUCOSA

B] T. SUBMUCOSAB] T. SUBMUCOSA

C] T. ADVENTITIAC] T. ADVENTITIA

11


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A]A] T. MUCOSAT. MUCOSA:: consisting ofconsisting of

Respiratory liningRespiratory lining PSEUDOSTRATIFIEDPSEUDOSTRATIFIED

COLUMNAR CILIATEDCOLUMNAR CILIATEDEPITHELIUMEPITHELIUM

with tall columnar ciliated cells,with tall columnar ciliated cells,

basal cells and some goblet cells.basal cells and some goblet cells. L.P.L.P. is a loose connective tissueis a loose connective tissue

with serowith sero--mucous glandsmucous glands

((tracheal glandstracheal glands). These are more). These are more

numerous within the posteriornumerous within the posteriorwall of the tracheawall of the trachea (membranous part).(membranous part).

Some lymphoid nodules.Some lymphoid nodules.

Blood vesselsBlood vessels (mainly capillaries).(mainly capillaries).11


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A]A] T. MUCOSAT. MUCOSA:: consisting ofconsisting of

Respiratory liningRespiratory lining PSEUDOSTRATIFIEDPSEUDOSTRATIFIED

COLUMNAR CILIATEDCOLUMNAR CILIATEDEPITHELIUMEPITHELIUM

with tall columnar ciliated cells,with tall columnar ciliated cells,

basal cells and some goblet cells.basal cells and some goblet cells. L.P.L.P. is a loose connective tissueis a loose connective tissue

with serowith sero--mucous glandsmucous glands

((tracheal glandstracheal glands). These are more). These are more

numerous within the posteriornumerous within the posteriorwall of the tracheawall of the trachea (membranous part).(membranous part).

Some lymphoid nodules.Some lymphoid nodules.

Blood vesselsBlood vessels (mainly capillaries).(mainly capillaries).8Trachea, l.s., H&E, LM x 270

E

SMG

LP

HC


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B]B] T. SUBMUCOSAT. SUBMUCOSA::

the fibrothe fibro--musculomusculo--cartilaginouscartilaginous

layer containslayer contains

CC--shaped (incomplete) ringsshaped (incomplete) rings

(16(16--20 pcs) of the20 pcs) of the hyaline cartilagehyaline cartilage

surrounded by a connective tissue,surrounded by a connective tissue,

openings of the rings are orientedopenings of the rings are oriented

to the posterior surface of theto the posterior surface of the

trachea and transversed withtrachea and transversed with

fibroelastic ligamentfibroelastic ligamentandand

Smooth muscle bundlesSmooth muscle bundles

(TRACHEALIS MUSCLE).(TRACHEALIS MUSCLE). 11


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C]C] T. ADVENTITIAT. ADVENTITIA::

Is composed of a looseIs composed of a loose

connective tissue withconnective tissue with

blood vesselsblood vessels..

Branches of peripheralBranches of peripheralnervesnerves and lobules ofand lobules of

adipose tissueadipose tissue..

It fixes the trachea to theIt fixes the trachea to the

surrounding connectivesurrounding connective

tissue oftissue of mediastinummediastinum..

11Childs trachea, overview, t.s., LM x 25Childs trachea, overview, t.s., LM x 25

Trachea LMTrachea LM

EE


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Trachea LMTrachea LM

8Layers of the wall of trachea, H&E, LM x 200

EE

LPLP

CC

AA

TRACHEOTOMYTRACHEOTOMY


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BRONCHIAL TREEBRONCHIAL TREE

The bronchial tree can be divided into:The bronchial tree can be divided into:

[A][A] EXTRAPULMONARYEXTRAPULMONARYBRONCHIBRONCHI-- Direct continuation of trachea beyondDirect continuation of trachea beyond

itsits bifucrationbifucration..

-- Located in theLocated in the mediastinummediastinum outsideoutside

lungs.lungs.

[B][B] INTRAPULMONARY BRONCHIINTRAPULMONARY BRONCHI-- Located inside lungs.Located inside lungs.

-- Always surrounded with alveoli andAlways surrounded with alveoli and

the other structures of the lung.the other structures of the lung.

[C] BRONCHIOLES[C] BRONCHIOLES

[D] TERMINAL BRONCHIOLES[D] TERMINAL BRONCHIOLES

[E] RESPIRATORY BRONCHIOLES[E] RESPIRATORY BRONCHIOLES 5


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BRONCHIAL TREEBRONCHIAL TREE

10

The bronchial tree can be divided into:The bronchial tree can be divided into:

[A][A] EXTRAPULMONARYEXTRAPULMONARYBRONCHIBRONCHI-- Direct continuation of trachea beyondDirect continuation of trachea beyond

itsits bifucrationbifucration..

-- Located in theLocated in the mediastinummediastinum outsideoutside

lungs.lungs.

[B][B] INTRAPULMONARY BRONCHIINTRAPULMONARY BRONCHI-- Located inside lungs.Located inside lungs.

-- Always surrounded with alveoli andAlways surrounded with alveoli and

the other structures of the lung.the other structures of the lung.

[C] BRONCHIOLES[C] BRONCHIOLES

[D] TERMINAL BRONCHIOLES[D] TERMINAL BRONCHIOLES

[E] RESPIRATORY BRONCHIOLES[E] RESPIRATORY BRONCHIOLES

O C SO C S


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[A][A] --PRIMARY BRONCHUSPRIMARY BRONCHUS

The structure is similar to trachea exceptThe structure is similar to trachea except

for the cartilage and smooth muscle !!for the cartilage and smooth muscle !!

The lamina propria is moreThe lamina propria is moredensedensewithwith

higher proportion of elastic fibers.higher proportion of elastic fibers.

SeroSero--mucousmucous glandsglandsand lymphocytesand lymphocytesare well developed.are well developed.

TheThe cartilagecartilage (hyaline) is irregular in(hyaline) is irregular in

shape and formsshape and forms incomplete rings orincomplete rings or

segments.segments. The smooth muscle layer in the laminaThe smooth muscle layer in the lamina

propria is ofpropria is of spiralspiralarrangement andarrangement and

progressively more prominent.progressively more prominent.17

Primary bronchus, van Gieson/Alcian blue, LM x 150

[B][B] INTRAPULMONARY BRONCHIINTRAPULMONARY BRONCHI[B][B] INTRAPULMONARY BRONCHIINTRAPULMONARY BRONCHI


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[B][B] -- INTRAPULMONARY BRONCHIINTRAPULMONARY BRONCHI[B][B] -- INTRAPULMONARY BRONCHIINTRAPULMONARY BRONCHI

Located inside lungsLocated inside lungs -- secondary,secondary,

tertiary etc., (diam.tertiary etc., (diam.>1 mm>1 mm).).

Their structure is similar to the primaryTheir structure is similar to the primary

bronchus but it has :bronchus but it has :

Less goblet cellsLess goblet cells in the respiratoryin the respiratoryepithelium.epithelium.

The cartilage is moreThe cartilage is more fragmentedfragmented

(incomplete profiles).(incomplete profiles).

Only a fewOnly a few serosero--mucous glands inmucous glands inlamina propria.lamina propria.

Bundles ofBundles of smooth musclesmooth muscle areare

more prominent.more prominent.










more prominent.more prominent.7



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Small bronchus, H&E stain, LM x 75











more prominent.more prominent.6



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(Cont.)(Cont.)

Numerous lymphocytes andNumerous lymphocytes and

lymphoid noduleslymphoid nodules ((BALTBALT))areare

located in the lamina propria withlocated in the lamina propria with

diapedesis of lymphocytesdiapedesis of lymphocytesthrough the epithelium.through the epithelium.

Each intrapulmonary bronchus isEach intrapulmonary bronchus is

accompanied by branches of theaccompanied by branches of the

pulmonary artery and veinpulmonary artery and vein+ lymphatic vessels,+ lymphatic vessels,

+ smaller bronchial artery.+ smaller bronchial artery.

7

Wall of a bronchus with lymphoid tissue LM x 250


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Intrapulmonary bronchusIntrapulmonary bronchus

[8]

Intrapulmonary bronchus, t. s., H&E, LM x 132

EE

SMSM

CC CC

[C][C] BRONCHIOLESBRONCHIOLES[C][C] BRONCHIOLESBRONCHIOLES


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[C][C] -- BRONCHIOLESBRONCHIOLES[C][C] -- BRONCHIOLESBRONCHIOLES

(( diameterdiameter< 1 mm< 1 mm))

TheyThey hahaveve the epithelium stillthe epithelium still


butbut ::

It is lower and withIt is lower and with very few gobletvery few goblet

cells.cells.

No glandsNo glands mucosal glands are inmucosal glands are in

lamina propria.lamina propria.

No cartilageNo cartilage is present in the wall.is present in the wall.

It has well developed continuousIt has well developed continuous

layer of spirallayer of spiral smooth musclesmooth muscle cellscells

and elastic fibers.and elastic fibers.

8Bronchiol, t.s., H&E, LM x 270

Lumen


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Bronchiol,LMBronchiol,LM

17

Bronchiol, t.s., H&E, LM x 160

[D][D] TERMINAL BRONCHIOLESTERMINAL BRONCHIOLES


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[D][D] -- TERMINAL BRONCHIOLESTERMINAL BRONCHIOLES

(( diam.diam. 0.30.3 -- 0.1 mm0.1 mm ))

It has :It has :

EpitheliumEpithelium simplesimplecolumnarcolumnar

ciliated (withciliated (withnono goblet cellsgoblet cells

butbutClara cellsClara cellsinsteadinstead).).

NoNo glands andglands and nono cartilage incartilage in


Elastic fibresElastic fibres

areare in lamina proprin lamina propriaia..

Thin layer ofThin layer of smooth musclesmooth muscle

hashas spiral arrangement.spiral arrangement.

8



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(( diam.diam. 0.30.3 -- 0.1 mm0.1 mm ))

It has :It has :

EpitheliumEpithelium simplesimplecolumnarcolumnar

ciliated (withciliated (withnono goblet cellsgoblet cells

butbutClara cellsClara cellsinsteadinstead).).

NoNo glands andglands and nono cartilage incartilage in


Elastic fibresElastic fibres

areare in lamina proprin lamina propriaia..

Thin layer ofThin layer of smooth musclesmooth muscle

hashas spiral arrangement.spiral arrangement.

8Lung, terminal bronchioles, H&E, LM x 132



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CLARA CELLSCLARA CELLSin the epithelium are:in the epithelium are:

NonNon--ciliatedciliatedcolumnar cells withcolumnar cells withindented nuclei.indented nuclei.

Contain membraneContain membrane--boundboundgranulesgranules(0.3 um in diam.)(0.3 um in diam.)

in their bulbous apical cytoplasm.in their bulbous apical cytoplasm.

They are secretory cells to produceThey are secretory cells to produce

glycosaminoglycansglycosaminoglycans andandcholesterol as a protective layer.cholesterol as a protective layer.

10


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Clara cellsClara cells

[7]Clara cells in the epithelium of a terminal bronchiole, Tol. blue stain, LM x 350

[E][E] RESPIRATORY BRONCHIOLESRESPIRATORY BRONCHIOLES


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Terminal

bronchioleElasticfibers

[E][E] -- RESPIRATORY BRONCHIOLESRESPIRATORY BRONCHIOLES

They make a transition between conductingThey make a transition between conducting

and respiratory portions of the lung.and respiratory portions of the lung.Their structure is identical to the terminalTheir structure is identical to the terminal

bronchioles but they:bronchioles but they:

Are linedAre lined onlyonly byby nonnon--ciliatedciliatedsimplesimple

cuboidal epithelium withcuboidal epithelium withClara cellsClara cells.. Have numerousHave numerous saccularsaccular alveolialveoli

attached to their wallsattached to their walls (as the first(as the firstspots of gas exchange)spots of gas exchange)which arewhich are

lined by simple squamous alveolarlined by simple squamous alveolarepithelium.epithelium.

TThey have some smooth musclehey have some smooth muscle

cells and elastic fibcells and elastic fibeersrs in the wall.in the wall.1

[E][E] RESPIRATORY BRONCHIOLESRESPIRATORY BRONCHIOLES


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[E][E] -- RESPIRATORY BRONCHIOLESRESPIRATORY BRONCHIOLES

They make a transition between conductingThey make a transition between conducting

and respiratory portions of the lung.and respiratory portions of the lung.Their structure is identical to the terminalTheir structure is identical to the terminal

bronchioles but they:bronchioles but they:

Are linedAre lined onlyonly byby nonnon--ciliatedciliatedsimplesimple

cuboidal epithelium withcuboidal epithelium withClara cellsClara cells.. Have numerousHave numerous saccularsaccular alveolialveoli

attached to their wallsattached to their walls (as the first(as the firstspots of gas exchange)spots of gas exchange)which arewhich are

lined by simple squamous alveolarlined by simple squamous alveolarepithelium.epithelium.

TThey have some smooth musclehey have some smooth muscle

cells and elastic fibcells and elastic fibeersrs in the wall.in the wall.8

Respiratory bronchiole, H&E, LM x 270

RBRB

[F][F] ALVEOLAR DUCTSALVEOLAR DUCTS


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[F][F] -- ALVEOLAR DUCTSALVEOLAR DUCTS

They are tiny tubular spacesThey are tiny tubular spaces

completely surrounded bycompletely surrounded byalveolialveoli..

TheyThey

Are lined with simple squamousAre lined with simple squamous

alveolar cells (alveolar cells ( type 1type 1).). Contain thin bundles of smoothContain thin bundles of smooth

muscle cells encircling the duct asmuscle cells encircling the duct as

well as its opening into alveoliwell as its opening into alveoli

((sphinctersphincter--like bundleslike bundles).). Are supported also by bundles ofAre supported also by bundles of

reticular and elastic fibers in theirreticular and elastic fibers in their

thin wall.thin wall.8

[G][G] ALVEOLIALVEOLI


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[G][G] -- ALVEOLIALVEOLI

ATRIAATRIA -- are initial portions ofare initial portions of

ALVEOLAR SACSALVEOLAR SACS(groups of alveoli).(groups of alveoli).

ALVEOLIALVEOLI -- are the terminal portionsare the terminal portions

of the bronchial tree directlyof the bronchial tree directly

responsible for Oresponsible for O22and COand CO22exchange.exchange.

they are sackthey are sack--like evaginationslike evaginations

(200(200 m in diam.) lined bym in diam.) lined by

veryvery thinthin simple squamoussimple squamous

epitheliumepitheliumcomposed ofcomposed of

2 kinds2 kindsof cells:of cells: Type I cellsType I cells

Type II cellsType II cells

8x 270

Alveolarduct

Alveolarsac

Alveolus

Alveolus

Alveolus

Alveolus

Alveolus

x 270



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1.1. Type I cellsType I cells ::((PneumocytePneumocyte I)I)

(SQUAMOUS ALVEOLAR CELLS,(SQUAMOUS ALVEOLAR CELLS,97 %97 %))TheyThey

are veryare veryflatflatcells with continuouscells with continuousplasma membraneplasma membrane

have organelles (GER, GA, M)have organelles (GER, GA, M)

located mainly around thelocated mainly around the

nucleusnucleus

have abundanthave abundant pinocytoticpinocytotic

vesicles located in the thin areasvesicles located in the thin areas

of the cytoplasmof the cytoplasm havehave desmosomesdesmosomesandand

occluding junctionsoccluding junctions to jointo join

the cells tightly togetherthe cells tightly together

7

Alveolus

Alveolus

Alveolus



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Alveolus

Alveolus


22.. Type II cells :Type II cells : ((PneumocytePneumocyte II)II)

(GREAT ALVEOLAR CELLS(GREAT ALVEOLAR CELLSor SEPTAL CELLS,or SEPTAL CELLS, 3 %3 %))

TheyThey

Are interspersed among theAre interspersed among the

type I cells.type I cells.

Are cuboidal or polygonal in shape,Are cuboidal or polygonal in shape,

found solitary or in groups infound solitary or in groups in

corners of alveoli.corners of alveoli.

AreAresecretory cellssecretory cellscontainingcontaining

several organelles (M, GER,several organelles (M, GER,

well developed GA), andwell developed GA), and

numerousnumerous microvillimicrovilli areare

on their apical surfaces.on their apical surfaces. 7



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22.. Type II cells:Type II cells:((PneumocytePneumocyte II)II)

(Cont.)(Cont.)

Have special membraneHave special membrane--limitedlimitedlamellar bodieslamellar bodies,, observedobserved

in their cytoplasm under EMin their cytoplasm under EM

(diam.1(diam.1--22 m), containingm), containing

phospholipids and proteins.phospholipids and proteins.

TheyThey produceproduce pulmonarypulmonary

surfactantsurfactant (which contains(which contains

dipalmitoyldipalmitoyl lecithin) to lowerlecithin) to lower

alveolar surface tension andalveolar surface tension and

to prevent alveoli fromto prevent alveoli from

collapsing during expiration.collapsing during expiration.

It also has bactericidal effect .It also has bactericidal effect .7

Alveolus

EM x 270

Alveolus


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Type II cellType II cell

7

INTERINTER--ALVEOLAR SEPTUMALVEOLAR SEPTUM


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INTERINTER--ALVEOLAR SEPTUMALVEOLAR SEPTUM

Is a very thin wall between twoIs a very thin wall between two

neighboring alveoli which consists of:neighboring alveoli which consists of:

11 -- Thin squamousThin squamous epithelial cellsepithelial cells((pneumocytespneumocytes I) on both sides.I) on both sides.

22 -- Blood capillariesBlood capillariessandwiched insandwiched inbetween the two layers of cells.between the two layers of cells.

33 -- InterstitiumInterstitiumwith reticular andwith reticular and

elastic fibers and some fibroblasts,elastic fibers and some fibroblasts,

mast cells and macrophagesmast cells and macrophages

(interstitial dust cells).(interstitial dust cells).

8

Alveolus

Alveolus

Alveolus

Lung, interalveolar septum, H&E, LM x 540

STRUCTURE OF THE BLOODSTRUCTURE OF THE BLOOD AIR BARRIERAIR BARRIER


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STRUCTURE OF THE BLOODSTRUCTURE OF THE BLOOD--AIR BARRIERAIR BARRIER

It is composed ofIt is composed of33componentscomponents11-- Cytoplasm of theCytoplasm of the flat alveolarflat alveolar

cellscells (type I.)(type I.)

22-- Fused basal laminaFused basal lamina ofof

apposed alveolar andapposed alveolar andendothelial cells.endothelial cells.

33-- Cytoplasm of the flatCytoplasm of the flat

endothelial cellsendothelial cells (which is(which is

the continuous type ofthe continuous type ofcapillary).capillary).

NoteNote :: 300 million alveoli in lungs300 million alveoli in lungs

= 140 m= 140 m22of exchange surface area.of exchange surface area.10

AIR

AIR

BLOOD



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= 140 m= 140 m22of exchange surface area.of exchange surface area.10Electron micrograph of lung alveoli, EM x 5800

AIR

AIR

BLOOD



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10

AIR

AIR

BLOOD

Electron micrograph of lung alveoli, EM x 5800









= 140 m= 140 m22of exchange surface area.of exchange surface area.



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11

AIR

AIR

BLOOD

7

DUST CELLSDUST CELLS


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TheyThey

Are cells derived fromAre cells derived from monocytesmonocytes..

Are found in the interior ofAre found in the interior of alveolaralveolarseptumseptum (interstitial(interstitial localilocalizzationation))

as well as on theas well as on the alveolar surfacealveolar surface

((intralveolarintralveolar localilocalizzationation, alveolar, alveolarmacrophages).macrophages).

Accumulate dust and otherAccumulate dust and othermicroparticlesmicroparticles and store themand store them

mainly within themainly within the perivascularperivascular

spaces and in the pleura.spaces and in the pleura.

SomeSome intralveolarintralveolar macrophages maymacrophages may

be expectorated or swallowed later.be expectorated or swallowed later.8

Lung, dust cells, H&E, LM x 270



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[8]

AIR

AIR

AIR

BLOOD

[8]

AIR

AIR

AIR

AIR

Lung, dust cells, H&E, LM x 540Lung, dust cells, H&E, LM x 540

ALVEOLAR PORESALVEOLAR PORES


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ALVEOLAR PORESALVEOLAR PORES

Pores of KohnPores of Kohn aarere

1010 -- 1515 m pores within them pores within theinteralveolarinteralveolar septum connectingseptum connecting

the neighboring alveoli.the neighboring alveoli.

They equalize pressure in theThey equalize pressure in the

alveoli and allow for collateralalveoli and allow for collateral

circulation (when necessary).circulation (when necessary).

11

L

2Lung, EM x 7000Lung, EM x 7000

[H][H] -- PLEURAPLEURA


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[H][H] PLEURAPLEURA

It is the serous membraneIt is the serous membrane

covering lungs withcovering lungs with 22 layers:layers:

1. parietal pleura1. parietal pleura

2. visceral pleura2. visceral pleura

Both layers are composed ofBoth layers are composed of

one layer ofone layer of MESOTHELIALMESOTHELIAL

CELLSCELLS(simple squamous(simple squamous epep.)..).

They are supported by fineThey are supported by fineconnective tissue layerconnective tissue layer

(with some elastic fibers).(with some elastic fibers).

7

[I][I] -- PULMONARY BLOOD VESSELSPULMONARY BLOOD VESSELS


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[I][I] PULMONARY BLOOD VESSELSPULMONARY BLOOD VESSELS

They are of two kinds:They are of two kinds:

1)1) Nutrient circulationNutrient circulation::(systemic)(systemic) These blood vessels follow theThese blood vessels follow the

bronchial tree up to the respiratorybronchial tree up to the respiratory

bronchioles and then they anastomosebronchioles and then they anastomose

with the functional circulation.with the functional circulation.

2)2) Functional circulationFunctional circulation::(pulmonary)(pulmonary)

Pulmonary arteries are thin walledPulmonary arteries are thin walled

with more smooth muscle and elasticwith more smooth muscle and elastic

fibers andfibers and prominent internalprominent internal

elastic membraneelastic membrane..

They branch alongside the bronchialThey branch alongside the bronchial

tree and their adventitia fusestree and their adventitia fuses

with the same layer of bronchi.with the same layer of bronchi.

Veins follow the same route.Veins follow the same route.

3

L

Bronchial artery, elast. stain, LM x 250Bronchial artery, elast. stain, LM x 250


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Histologic features in the course of theHistologic features in the course of the

bronchial treebronchial tree

10

DEVELOPMENT OF THE RESPIRATORY SYSTEMDEVELOPMENT OF THE RESPIRATORY SYSTEM


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CONTENTSONTENTS

ORIGIN OF THE RESPIRATORY PRIMORDIUMORIGIN OF THE RESPIRATORY PRIMORDIUM (RESP. DIVERTICULUM)(RESP. DIVERTICULUM)

DEVELOPMENT OF THE LARYNXDEVELOPMENT OF THE LARYNX

DEVELOPMENT OF EXTRAPULMONARY BRONCHIDEVELOPMENT OF EXTRAPULMONARY BRONCHI

DEVELOPMENT OF INTRAPULMONARY BRONCHIAL TREEDEVELOPMENT OF INTRAPULMONARY BRONCHIAL TREE

DEVELOPMENT OF LUNG ALVEOLIDEVELOPMENT OF LUNG ALVEOLI

SEPARATION OF THE THORACAL CAVITYSEPARATION OF THE THORACAL CAVITY



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TheThe primordiumprimordium of the lowerof the lower

respiratory system developsrespiratory system developsas an outgrowth from theas an outgrowth from the

ventral wall of the foregutventral wall of the foregut

calledcalled respiratoryrespiratory

diverticulumdiverticulum.. TheThe epitheliumepithelium of the resp.of the resp.

diverticulumdiverticulum is ofis of

endodermalendodermal originorigin..

TheThe cartilaginouscartilaginousandandmuscularmuscularcomponents arecomponents are

derived from thederived from the

surroundingsurrounding splanchnicsplanchnic

mesodermmesoderm..x



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Initially the respiratoryInitially the respiratory diverticulumdiverticulum communicatescommunicates widely with the foregut,widely with the foregut,

but later thebut later the esophagotrachealesophagotracheal ridgesridgesappear and theappear and the esophagotrachealesophagotrachealseptumseptumdevelops to separate the respiratory and digestive canals.develops to separate the respiratory and digestive canals.

x

4 weeks 5 weeks



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TheThe internal lininginternal lining develops from thedevelops from theendodermendoderm of the upper portion ofof the upper portion of

the respiratorythe respiratory diverticulumdiverticulum ((laryngolaryngo--tracheal tube).tracheal tube). TheThe laryngeal orificelaryngeal orificechanges from achanges from a sagittalsagittal slitslit to ato a TT--shapedshaped

opening due to the development of pairedopening due to the development of paired arytenoidarytenoid swellingsswellings..

The epiglottis develops from theThe epiglottis develops from theepiglottal swellingepiglottal swellinglocated ventrally tolocated ventrally to

the orifice.the orifice. TheThe laryngeal epithelium proliferateslaryngeal epithelium proliferates rapidly andrapidly andtemporary closestemporary closes

lumen of the developing larynx.lumen of the developing larynx.

x

4 weeks 5 weeks



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RecanalizationRecanalizationoccurs by theoccurs by the 1010ththweekweekand theand the laryngeal ventricleslaryngeal ventricles formform

subsequently.subsequently. The folds of tissue on both sides of the recess differentiate into theThe folds of tissue on both sides of the recess differentiate into the falsefalseandand

true vocal cordstrue vocal cords..

TheThe laryngeal cartilageslaryngeal cartilages( thyroid,( thyroid, cricoidcricoid and arytenoids) develop from theand arytenoids) develop from the

mesenchymemesenchyme of the last twoof the last two branchialbranchial arches (arches (44thth

+ 6+ 6thth

).). TheThe laryngeal muscleslaryngeal musclesdevelop fromdevelop from myoblastsmyoblasts in the 4th and 6thin the 4th and 6th

branchialbranchial arches.arches.

x

6 weeks 10 weeks

DEVELOPMENT OF THE TRACHEADEVELOPMENT OF THE TRACHEA


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TheThetracheatrachea developsdevelopsfrom thefrom the distaldistalportion of theportion of the laryngotracheallaryngotracheal tubetube..

ItsIts endodermendodermgives rise to thegives rise to theepitheliumepithelium andandglands.glands.

TheTheconnective tissue, cartilage and musclesconnective tissue, cartilage and muscles of the trachea develop fromof the trachea develop from

the surroundingthe surrounding splanchnicsplanchnic mesenchymemesenchyme..

TheThe distal enddistal endof theof the laryngotracheallaryngotracheal tube swells and forms thetube swells and forms the lung budlung budwhich divides soon (5which divides soon (5thth week) to form two branchesweek) to form two branches -- thethe right and leftright and left

bronchial buds.bronchial buds.

x

6 weeks 10 weeks

DEVELOPMENT OF EXTRAPULMONARY BRONCHIDEVELOPMENT OF EXTRAPULMONARY BRONCHI


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TheThe right branchright branch soon divides intosoon divides intothree main branchesthree main branchesand theand the leftleft

branchbranch divides intodivides intotwo main branchestwo main branches (secondary bronchi).(secondary bronchi).

TheThe endodermalendodermal bronchial and lung buds grow in distal and lateral directionsbronchial and lung buds grow in distal and lateral directions

and penetrate theand penetrate thepericardioperitonealpericardioperitoneal canalscanalsfrom which thefrom which the pleuralpleural

cavitycavity develops when it is separated from the peritoneal and pericardialdevelops when it is separated from the peritoneal and pericardial

cavities by projections calledcavities by projections called pleuropericardialpleuropericardial foldsfolds..

x

10 weeks

INTRAPULMONARY BRONCHIAL TREEINTRAPULMONARY BRONCHIAL TREE


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TheThe intrapulmonary bronchial treeintrapulmonary bronchial treedevelops during furtherdevelops during further

dichotomousdichotomousdivisions of thedivisions of thesecondary bronchi to supply thesecondary bronchi to supply the

pulmonary lobes withpulmonary lobes with segmentalsegmental

bronchibronchiand bronchi ofand bronchi oflowerlower

ordersorders..

By the end of theBy the end of the66thth monthmonth

approximatelyapproximately 1717generationsgenerations

of subdivided bronchi are formedof subdivided bronchi are formedto reach the level of respiratoryto reach the level of respiratory

bronchioles.bronchioles.

== PRENATAL STAGEPRENATAL STAGEx



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AdditionalAdditional 6 generations6 generationsdevelopdevelop

during theduring thePOSTNATAL STAGEPOSTNATAL STAGE

of the lung growth.of the lung growth.

While the trachea and theWhile the trachea and thebronchial tree elongatebronchial tree elongate

the lungsthe lungs migrate caudallymigrate caudally

and by the time of birth theand by the time of birth the

bifurcation of the trachea isbifurcation of the trachea isfound opposite thefound opposite the

44ththThThvertebra.vertebra.

x



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The bronchial liningThe bronchial lining

epitheliumepithelium andand glandsglandsdevelop from thedevelop from theendodermendoderm

of the lung bud.of the lung bud.

TheThe connective tissueconnective tissue,,

cartilagenouscartilagenous plates and theplates and thesmooth musculature developssmooth musculature develops

from thefrom the surroundingsurrounding

mesenchymemesenchyme..

The visceral and parietalThe visceral and parietalsheets of thesheets of the pleurapleuradevelopdevelop

fromfrom splanchnicsplanchnic and parietaland parietal

layers of thelayers of the mesenchymemesenchyme..x



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Stage 1Stage 1

PSEUDOGLANDULAR PERIODPSEUDOGLANDULAR PERIOD

[ 1[ 1 -- 4 month ]4 month ]

The intrapulmonary airways developThe intrapulmonary airways developinto tubes terminated byinto tubes terminated by aciniacini linedlinedbyby tall columnar epithelial cellstall columnar epithelial cells

( resembling glands ).( resembling glands ).

Blood capillariesBlood capillariesare rare andare rare and

separatedseparated from the liningfrom the liningepithelium by a layer of a looseepithelium by a layer of a looseconnective tissue (no sacs or alveoliconnective tissue (no sacs or alveoliare present.are present.

Respiration is not possible.Respiration is not possible.x



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PSEUDOGLANDULAR PERIODPSEUDOGLANDULAR PERIOD

[ 1[ 1 -- 4 month ]4 month ]x



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Stage 2Stage 2

CANALICULAR PERIODCANALICULAR PERIOD[ 4[ 4 -- 6 month ]6 month ]

LuminaLuminaof the bronchi an terminalof the bronchi an terminal

bronchioles becomebronchioles become largerlarger..

The terminal bronchioles give riseThe terminal bronchioles give rise

toto respiratory bronchiolesrespiratory bronchioles..

Their terminal parts are lined withTheir terminal parts are lined with

simple cuboidal epithelium.simple cuboidal epithelium.

The loose connective tissueThe loose connective tissue

surrounding the terminal airwayssurrounding the terminal airways

isismoremore vascularizedvascularized.. x



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Stage 3Stage 3

TERMINAL SAC PERIODTERMINAL SAC PERIOD

[ 6 month[ 6 month -- full term ]full term ]

ManyManyterminal sacsterminal sacsdevelop anddevelop and

theirtheir epitheliumepitheliumbecomesbecomes very thinvery thin(simple squamous,(simple squamous,type I alveolartype I alveolar

cellscells) =) = primitive alveoli.primitive alveoli.

Type II alveolar cellsType II alveolar cells develop anddevelop and

start to producestart to produce surfactant.surfactant. CapillariesCapillaries begin tobegin to bulgebulgeinto theinto the

primitive alveoli and acquire anprimitive alveoli and acquire an

intimate contactintimate contactwith the flat epithelial cells (respiration is possible).with the flat epithelial cells (respiration is possible).

Lymphatic capillariesLymphatic capillariesdevelop from the loosedevelop from the loose mesenchymalmesenchymal tissue.tissue.x



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Stage 4Stage 4

ALVEOLAR PERIODALVEOLAR PERIOD

[ late fetal[ late fetal -- to 8 years ]to 8 years ]

Alveolar lining attenuates toAlveolar lining attenuates to

extremely thin squamousextremely thin squamous

epithelial layer and many newepithelial layer and many new

alveoli developalveoli develop

Surrounding capillaries protrudeSurrounding capillaries protrude

into the alveoli and theinto the alveoli and the bloodbloodairairbarrier is thinbarrier is thin (ready for(ready forrespiration)respiration)

Mature alveoli do not appearMature alveoli do not appear

before birthbefore birth !!!!!! x


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HISTOGENESISHISTOGENESIS

OF THE LUNGOF THE LUNG

x

PSEUDOGLANDULAR

CANALICULAR TERMINAL SAC

Overview of lung developmentOverview of lung development


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PERINATAL AND POSTNATAL LUNGSPERINATAL AND POSTNATAL LUNGS
http://localhost/var/www/apps/conversion/tmp/scratch_10/Movies/Development%20of%20respiratory%20system.flv


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Some discontinuousSome discontinuous breathing movements occur before birthbreathing movements occur before birthand causeand cause

aspiration of some amniotic fluid into the lungs.aspiration of some amniotic fluid into the lungs. Before birth theBefore birth the lungs are filled with fluidlungs are filled with fluidwhich containswhich contains ClCl--, proteins, some, proteins, some

mucus and surfactant. The amount of surfactant increases duringmucus and surfactant. The amount of surfactant increases during

the last two weeks before birth.the last two weeks before birth.

When respiration begins at birth most of theWhen respiration begins at birth most of the lung fluid islung fluid is resorbedresorbedby theby theblood and lymph capillaries. At this stage the surfactant remains depositedblood and lymph capillaries. At this stage the surfactant remains deposited

on the alveolar walls and prevents the alveoli to collapse during expirationon the alveolar walls and prevents the alveoli to collapse during expiration

phase. (In stillborn infant the lung fluid is notphase. (In stillborn infant the lung fluid is not resorbedresorbed -- it sinks whenit sinks when

placed in water.)placed in water.) Respiratory movementsRespiratory movements after birth cause the air to enter the lungsafter birth cause the air to enter the lungs whichwhich

subsequently expand and fill the pleural cavity.subsequently expand and fill the pleural cavity.

TheThe postnatal growth of the lungspostnatal growth of the lungsis mainly due to an increase in the numberis mainly due to an increase in the number

of theof the respiratoryrespiratory bronchiolibronchioli and alveoliand alveoli(first 10 years of the postnatal life).(first 10 years of the postnatal life).x

RESPIRATORY DISTRESS SYNDROME :RESPIRATORY DISTRESS SYNDROME :


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A clinical noteA clinical note::

It may develop in premature infants with weights up to 1.5 kg.It may develop in premature infants with weights up to 1.5 kg.

It is caused by deficiency of the pulmonary surfactant.It is caused by deficiency of the pulmonary surfactant.

The lungs are underinflated (partially collapsed) and the alveoli containThe lungs are underinflated (partially collapsed) and the alveoli contain

a fluid with high protein content and many hyaline membranesa fluid with high protein content and many hyaline membranes

(hyaline membrane disease).(hyaline membrane disease).

The infants develop rapid, labored breathing.The infants develop rapid, labored breathing.

x


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The EndThe End

ThisThispresentationpresentationwaswascompiledcompiledonlyonlyforforinternalinternaluseusebyby

medicalmedicalstudentsstudentsatatthetheFacultyFacultyofofMedicine,Medicine,

PalackPalackUniversity, CZ.University, CZ.

ItItcancannotnotbebedistributeddistributedbybyanyanymeans.means.DK.DK.

REFERENCESREFERENCES


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11 3322 44

88

55

66 9977 1010

Reference numbers are given in the right bottom corner of pictures.Reference numbers are given in the right bottom corner of pictures.

Some of the pictures and schematics shown in this presentation were scanned

from the following textbooks or CD ROMs:



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1111 12121313 1414 1515

17171616






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(1) Kierszenbaum A.L.: Histology and Cell biology, Mosby, London, 2002

(2) Fawcett D.W., Jensh R.P.: Concise Histology, Chapman&Hill, New York, 1997

(3) Stevens A., Lowe J.: Human Histology, 2nded., Mosby, London, 2000

(4) Cormack D.H.: Essential Histology, Lippincott-Raven, Philadelphia, 1997

(5) Cohen B.D., Wood D.L.: Structure and Function of the Human Body,

7thed. Lippincott Williams & Wilkins, Philadelphia, 2000

(6) Kerr J.B.: Atlas of Functional Histology, Mosby, London, 2000

(7) Junqueira L.C., Carneiro J., Kelly R.O.: Basic Histology, Text and Atlas

Lange McGraw-Hill, New York, 2003

(8) Gartner L.P., Hiatt J.L.: Color Atlas of Histology, 3rded., Wiliams&Wilkins,

Baltimore, 19949)

(9) Krstic R.V.: Illustrated encyclopedia of Human Histology, Springer Verlag,

Berlin. 1984Reference numbers are given in the right bottom corner of pictures.Reference numbers are given in the right bottom corner of pictures.





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(10) Ross M.H., Kaye G.I., Pawlina W.: Histology, text and atlas, 4thed., Lippincott

Williams & Wilkins, Philadelphia, 2003

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Biology, Springer-Verlag, Berlin, 1991

(12) Ross M.H., Reith E.J.: Histology, Text and Atlas, Harper& Row, Lippincott Co.,

New York, 1985

(13) Roroschenko V.P.:Di Fiores Altlas of Histology with Functional correlations, 9thed., Lippincott Williams & Wilkins, Philadelphia, 2000

(14) Lamberti A., MarinoT., Sodicoff M: The Histology lab assistant. Interactive CD-

ROM , AGC Educational Media,

(15) Sadler T.W.: Langmans Medical Embryology, 8thed., Lippincott Williams &

Wilkins, Philadelphia, 2000

(16) Gartner L.P., Hiatt J.L.: Color Textbook of Histology, 2nded., W.B. Saunders Co.,

Philadelphia, 2001

(17) Wheater PR, Burkitt HG, Daniels VG: Functional Histology, text and colour atlas,

2nded., Churchill Livingstone, London, 1987




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http://www.udel.edu/biology/Wags/histopage/colorpage/cre/cre.htmhttp://www.udel.edu/biology/Wags/histopage/colorpage/cre/cre.htm

http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Respiratory/respir.htmhttp://www.lab.anhb.uwa.edu.au/mb140/CorePages/Respiratory/respir.htm

https://histo.life.illinois.edu/histo/atlas/showcat.php?cat_to_show=M&w=500https://histo.life.illinois.edu/histo/atlas/showcat.php?cat_to_show=M&w=500

http://www.anatomyatlases.org/MicroscopicAnatomy/Section11/Section11.shtmlhttp://www.anatomyatlases.org/MicroscopicAnatomy/Section11/Section11.shtml

http://www.path.uiowa.edu/cgihttp://www.path.uiowa.edu/cgi--binbin--pub/vs/fpx_browse.cgi?cat=o_lung&div=nlmpub/vs/fpx_browse.cgi?cat=o_lung&div=nlm

http://zoomify.lumc.edu/respiratory/respiratory_main.htmhttp://zoomify.lumc.edu/respiratory/respiratory_main.htm

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