desarrollo sistema faringeo - respiratorio

8/14/2019 Desarrollo Sistema Faringeo - Respiratorio

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Desarrollo sistema faringeo -Desarrollo sistema faringeo -

respiratoriorespiratoriom.c. Roberto Pahuacho Dazm.c. Roberto Pahuacho Daz


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Primitive Pharynx

5 ridges appear

called pharyngeal

arches 1, 2, 3, 4, 5(6)

1

32 4, 6


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1st arch

2nd arch

3rd arch

4th arch

1st pouch artery

1st cleft

cartilage

nerve

Cada arco faringeo esta formado por:

-Cartlago

-Arco aortico

-Nervio craneal

-mesenquima


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First Pharyngeal Arch

First arch developsinto 4 prominences: Two maxillary

prominences

Two mandibular

prominences


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Development of the

External Auditory Meatus

sFirst Pharyngeal Cleft gives rise to the externalauditory meatus.s1st and 2nd arches give rise to external ear

1st arch

2nd

arch3rd arch

4th arch

1st pouch

external

auditorymeatus

auditory

tube


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1st arch

2nd

arch3rd arch

4th arch

1st pouch

externalauditorymeatus

auditorytube

Cervical sinus

The region between the 2nd arch andthe 3rd, 4th and 6th arches is called thecervical sinus.

cervical

si

nus


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Ectoderm

1st Arch skin over maxilla, mandible, some around

the ear and external auditory meatus salivary glands

enamel of teeth

epithelium of buccal cavity epithelium over anterior body of the tongue


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Ectoderm

Second Arch epithelium over part of external auditory

meatus some epithelium behind the ear


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Ectoderm

Third Arch epithelium around the ear

Fourth Arch epithelium around the ear


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Development of the Tongue

Tongue develops where the stomodeumand pharynx meet.

1st arch

2nd arch

3rd arch

4th arch hypobranchialeminence

epiglottal

swelling

tuberculum

impar1st cleft

lingual

swelling artery

cartilage


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1st arch

2nd arch

3rd arch


epiglottal

swelling

tuberculum

impar1st cleft

lingual

swelling artery

cartilage


Lingual swellings and tuberculum impardevelop from the first arch.


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Epiglottic swellings develop at the level ofthe 4th arch.

1st arch

2nd arch

3rd arch


epiglottal

swelling

tuberculum

impar1st cleft

lingual

swelling artery

cartilage


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Foramen

Cecum

s Lateral lingualswellings fromfirst arch give rise

to mucosa ofanterior 2/3 of thetongue.


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Hypobranchialeminence mostlyfrom 3rd arch

gives rise to theposterior 1/3 ofthe tongue.


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The epiglottisand the mostposterior part of

the tongue arederived from the4th arch.



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Note that there islittle if anycontribution from

the 2nd arch.



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Tongue Musculature

Myoblasts fromoccipital somitesgive rise to most

of the tonguemuscles and areinnervated by the

hypoglossalnerve.


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Development of Tongue Summary

EmbryonicTissue

DevelopmentalIntermediate

Adult Organ Nerve

First Arch Lingual swellings Mucosa of Anterior 2/3 ofTongue

CN V

Second Arch HypobranchialEminence

-

Third Arch HypobranchialEminence

Mucosa of Posterior 1/3 ofTongue

CN IX

Fourth Arch HypobranchialEminence

Mucosa of the mostposterior tongue and

epiglottis

CN X

OccipitalSomites

Tongue Muscles CN XII


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Development of the Thyroid

The thyroid develops as a diverticulum from theforamen cecum.

Foramen cecum is located between the tuberculumimpar and the hypobranchial eminence.

1st arch

2nd arch

3rd arch4th arch hypobranchial

eminence

epiglottal

swelling

tuberculumimpar

1st cleft

lingualswelling artery

cartilage

Foramen

Cecum


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The thyroid develops as a diverticulum fromthe foramen cecum.

Foramen cecum is located between thetuberculum impar and the hypobranchialeminence.

1st arch

2nd arch

3rd arch4th arch hypobranchial

eminence

epiglottal

swelling

tuberculumimpar

1st cleft


cartilage

Foramen

Cecum


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The thyroid develops as a diverticulum from theforamen cecum.

Foramen cecum is located between the tuberculumimpar and the hypobranchial eminence.

1st arch

2nd arch

3rd

arch4th arch hypobranchial

eminence

epiglottal

swelling

tuberculumimpar

1st cleft


cartilage

Foramen

Cecum


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The thyroiddescends in

front of thepharynx.

Thryoglossal Duct


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The thyroid glandremains in contactwith the pharynx for

a period of time bya narrow duct calledthe thyroglossal

duct.

Thryoglossal Duct


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Path ofmigration ofthe thyroid.

Thyroid gland

D l t f th


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Development of the

Tonsils

Second pouch endoderm and mesoderm givesrise to: Palatine tonsillar fossa.

Secondarily lymphatic tissue is incorporated into thepouch.

1st pouch

2nd pouch

3rd pouch

4th (5th?)

pouch


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Development of the

Thymus

Endoderm of the third pouch proliferates andgives rise to the thymus during week 4.

First start as endodermal tubes.

This tissue envades the mesoderm.1st pouch

2nd pouch

3rd

pouch

4th (5th?)

pouch


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1st pouch

2nd pouch

3rd pouch

4th (5th?)

pouch

Development of the Thymus

Thymic tissue then loses connectionwith the pharynx.

Thymus descends during weeks 4 - 7.


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Development of the Thymus

Thymus reticularepithelium isderived fromendoderm.

Hassalscorpusclesdevelop from 3rdcleft ectoderm.

Lymphoid tissueinfiltrates later.

Thyroid

Thymus

D l f h


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Development of the

Parathyroids

Inferior parathyroids develop from thethird pouch at week 5.

Detach from pharynx and descend.1st pouch

2nd pouch

3rd pouch

4th (5th?)

pouch

D l t f th


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Development of the

Parathyroids

End up at theinferior pole ofthe dorsum of

the thyroid byweek 7.

Inferior

parathyroids

D l f h


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Development of the

Parathyroids Superior parathyroids develop from the

fourth pouch at week 5.

Detach from pharynx and descend.

Development of the


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Development of the

Parathyroids

End up at thesuperior pole of

the dorsum ofthe thyroid byweek 7. Superior

parathyroids

Inferior

parathyroids

D l t f th f lli l


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Development of the parafollicular

cells of the thyroid

Parafollicular cells of the thyroid are the Ccells that produce calcitonin.

The fifth pouch gives rise to the

ultimobranchial body.1st pouch

2nd pouch

3rd pouch

4th (5th?)

pouch


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Development of the parafollicular

cells of the thyroid Ultimobranchial body becomes

incorporated into the thyroid.

C cells actually develop from neuralcrest cells that invade theultimobranchial body.


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Development of the Muscles

of the Pharyngeal Arches First arch mesoderm

Gives rise to all the muscles of mastication

plus 4 - two tensors and two others: tensor tympani

tensor veli palatini

mylohyoid

anterior belly of the digastric

SVE - from branchial arches


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of the Pharyngeal Arches Second arch mesoderm

Gives rise to all the muscles of facial

expression plus three others: stapedius

stylohyoid

posterior belly of the digastric

SVE


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of the Pharyngeal Arches Third arch mesoderm

Gives rise to the stylopharyngeus

SVE


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of the Pharyngeal Arches Fourth arch mesoderm

Gives rise to all the striated muscles of the:

pharynx larynx

palate

SVE


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Development of the cartilage

from the Pharyngeal Arches First arch mesoderm gives rise to:

maxillary and mandibular bones

incus malleus


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from the Pharyngeal Arches Second arch mesoderm gives rise to:

stapes

styloid process (neural crest cells) body and lesser horn of hyoid (neural crest

cells)


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from the Pharyngeal Arches Third arch mesoderm gives rise to body

and greater horns of the hyoid (neural

crest cells.


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from the Pharyngeal Arches Fourth arch mesoderm gives rise to

laryngeal cartilages.


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Development of the Blood

Supply of the Pharyngeal Arches

Dorsal Aorta

Ventral Aorta

1st Aortic Arch

3rd Aortic Arch4th Aortic Arch

5th Aortic Arch

6th Aortic Arch

2nd Aortic Arch

7thIntersegmental

Artery

AorticSac

InternalCarotid

ExternalCarotid

PulmonaryTrunk

R. Common

Carotid

DuctusArteriosus

L.Subclavian

ArteryDescendingAorta

R. PulmonaryArtery

R. SubclavianArtery

L.Pulmonary

Artery


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Development of the Innervations

of the Pharyngeal Arches First arch is innervated by the 5th

cranial nerve.

Second arch is innervated by the 7thcranial nerve. Third arch is innervated by the 9th

cranial nerve. Fourth arch is innervated by the 10thcranial nerve.


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First Arch SummaryGerm Layers Presented 1st Arch

Surface Ectoderm Epithelium of buccal cavity, jaws, body of external

auditory meatus, and tympanic membrane.

Neural Ectoderm Maxillary and mandibular divisions of CN V.

Aortic Arches Degenerates.

Skeleton Maxillary and mandibular bones.

Meckels cartilage: malleus, incus, spheno-

mandibular ligament.

Muscles Masticatory, anterior belly of digastric, tensortympani, tensor palatini, and mylohyoid.

Endoderm of floor Tuberculum impar (body of tongue), lateral swelling.

Endoderm of pouches Eustachian (auditory) tube.


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Second Arch Summary

Germ Layers Presented 2nd Arch

Surface Ectoderm Epithelial portion of external auditory meatus and

cervical sinus.

Neural Ectoderm CN VII.

Aortic Arches Degenerates.

Muscles All muscles of facial expression plus, stapedius,

stylohyoid and post. Belly digastric

Endoderm of floor Thyroid (foramen cecum with 1st

)

Endoderm of Pouch Crypts of palatine tonsil in tonsillar fossa

Skeleton Reicherts cartilage: stapes, styloid process, body &

lesser cornua of hyoid, and stylohyoid ligament.


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Third Arch Summary

Germ Layers Presented 3rd Arch

Surface Ectoderm Epithelium around ear.

Neural Ectoderm CN IX.

Aortic Arches Stem of internal carotid artery and part of carotid

artery.

Skeleton Body & greater cornua of hyoid.

Muscles Stylopharyngeus

Endoderm of floor copula

Endoderm of pouches inferior parathyroids, thymus


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Fourth Arch Summary

Germ Layers Presented 4th & 5th (6th) Arches

Surface Ectoderm Epithelium around ear.

Neural Ectoderm CN X and maybe some CN XI.

Aortic Arches 4th arch: arch of aorta & part of right subclavian.

6th arch: pulmonary arteries and ductus arteriosus.

Skeleton Laryngeal cartilages.

Muscles Pharyngeal & laryngeal muscles.

Endoderm of floor Root of tongue, epiglottis & pharynx.

Endoderm of pouches Dorsal: superior parathyroids (4th).

Ultimobranchial body.


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desarrollo sistema faringeo - respiratorio

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