Dev of Eye, Ear, Face, Brain, Heart, Lungs

8/13/2019 Dev of Eye, Ear, Face, Brain, Heart, Lungs

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DEVELOPMENT OF EYE

• Eye primordia appear D22 as optic sulcus in neural folds at forebrain which

fuse.

Optic sulci optic vesicle optic cusps lens placode lens pit lensvesicle

Invag invag thickens invag + sinks ends fuse

• Optic vesicle grows laterally on each side and its conn w/ forebrain narrows -

optic stalk .

• ens vesicle and optic cusp derive from ectoderm and are surrounded w/

mesenchyme

ET!N" DEVELOPMENT#

• Develops from optic cusp.

• Outer layer ! pigment ep"Inner layer ! differentiates into layers #rod" cone" bipolar" and ganglion cells$

• Intraretinal space" btw outer and inner layers disappears so that pigment ep

and retinal layers fuse.

• %unction of pigment layer w/ layer of rods and cones is not so firm so that

detachment of retina may occur.

• Ed$e of optic cusp gives ciliary ep. and posterior ep% o& iris%

M!DDLE "ND E'TEN"L L"YE DEVELOPMENT#

• Develop from mesenchyme that envelops optic cusp.

•Lens vesicle LEN(

• "nterior )all of vesicle gives anterior ep% o& lens

• Posterior )all cells lengthen lens &i*ers.

• ens capsule ! epith cells of both pts of lens vesicle

• &utrition of lens from hyaloid artery #branch of ophthalmic artery$. 'ound in

vitreous body - hyaloid canal

• "nterior eye cham*er develops as space formed btw lens capsule and

ectoderm%

• +ornea develops from surface ectoderm and mesenchyme after ant chamber

is formed.

• Optic stalk - optic nerve

DEVELOPMENT OF E"

T,E E'TEN"L E"#

E-t "coustic meatus#

(. Derive from .st *ranchial $roove/ ectodermal cells proliferate and e)tend

inwards as meatal plu$%

*. ells of plu$ then de$enerate" forming cavity - e-ternal acoustic meatus.

"uricle#

(. 'rom 0 s)ellin$s known as auricle hillocks.


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*. , hillocks are on .st *ranchial 1mandi*ular arch and , on the 2nd 1hyoid

*ranchial arch%

,. End of *nd month all hillocks fuse ! pinna%

Tympanic mem*rane# from membrane btw .st *ranchial $roove n .st pharyn$eal

pouch/ made of ectoderm and endoderm and mesenchyme btw.

esenchyme - &i*rous stratum of tm" Ectoderm - epidermal

Endoderm - mucous of .

T,E M!DDLE E"#

• Develops from .st pharyn$eal pouch and cartilages of .st32nd pharyn$eal

arches%

• Tympanic cavity# (st pharyngeal pouch - distal pt e)panded envelopes

auditory ossicles.

• Pro-imal une-panded pt Eustachian tu*e

•

"uditory ossicles# malleus and incus from dorsal pt of Meckel4s cartila$e. #supporting (st branchial or mandibular arch$

• (tapes# from dorsal pt of eichert4s cartila$e #supporting *nd or hyoid

branchial arch$

• During late fetal period" tympanic cavity e)pands into temporal bone !

mastoid antrum%

T,E !NNE E"# 0k 1" derives from thickened plate of ectoderm 2

OT!+ PL"+ODE OT!+ P!T OT!+ VE(!+LE 1otocyst

Invag and sink edges primordium of fut memb labyrinth

below into mesench fuse lies lat to rhombencephalon

* divisions

Dorsal3 utricular pt# into utricle/semicircular ducts/ endolymphatic duct

Ventral3 saccular pt# into saccule/ cochlear duct

Dorsal diverticula 5 develops semicircular ducts" central pts fuse and disapp.

Ventral diverticula 5 develops cochlea

1th month" differentiation of maculae" cristae - begins in utricle.

3accule" semicircular ducts and organ of orti - in cochlear duct.

esenchyme around otic vesicle differentiates and forms bony labyrinth 3pace fills w/ perilymph.

DEVELOPMENT OF 6"!N "ND (%+

pro) pt broad! *rain

Neural plate neural $roove limited by neural &olds neural tu*e

narr caud pt ! (+

D(4 invaginates End of wk, fuse separates from ecto and is located

5tw it and notochord


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(. 0hen neural folds fuse" neuroectodermal cells separate and form on dorsal pt of

tube - neural crest. &eural crest cells give cells of spinal $an$lia and of

autonomic $an$lia%

*. 0all of neural tube initially has 6 ep. ells then proliferate" but later mitotic

activity is reduced" as a result wall of neural tube differentiates into * 7ones

- inner $erminative and outer mar$inal%,. In 8erminative 7one cells continue in their mitotic activity and migrate

peripherally. 0all of neural tube has , layers

- Ependymal layer ! ependyma"

- !ntermediate or mantle layer ! 8 cells differentiate into neuroblasts and

spongioblasts

- Mar$inal layer ! 0

DEVELOPMENT OF (+#

• Develops from caudal pt of neural tube.

• In lateral walls of neural tube" cells proliferate and dorsal and ventral pts

remain thin.

• ongit groove divides lateral walls into dorsal pt alar plate 2 dorsal horn

ventral pt *asal plate - ventral horn%

Initially" 3. is same length of vertebrate column but further development means

vertebrate column grows rapidly than 3. and so its caudal pt lies at higher level.

#terminates at ($

DEVELOPMENT OF T,E 6"!N

• Develops from cranial pt of neural tube

• 0k 1" , brain vesicles occur- The &ore*rain 7 prosencephalon

7 The mid*rain 7 mesencephalon

7 The hind*rain 7 rhom*encephalon

During wk 9" the forebrain and hindbrain divides so that 9 secondary vesicles arise

6rosencephalon 2 elencephalon

Diencephalon

esencephalon esencephalon

:hombencephalon etencephalon

yencephalon

F"+E DEVELOPMENT #0k 1-(;$

(. 9 prominences

- 'rontonasal ! mesenchyme near brain

- a)illary ! sup pt of (st pharyngeal arch

- andibular ! inf pt of *nd pharyngeal arch

*. Nasal placodes develop on frontonasal prominence

,. Nasal pits appear in nasal placodes and rest of placode divides into medial and

lat proc #btw lat nasal proc and ma) prom ! nasolacrimanl groove$

1. Medial nasal prominence fuse to form inter max segment 9. Intermaxillary segment


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=. 6alate development ! *o plate formed from * palatine sh> which are tissue

e)tensions from ma)illary prominence. 0hich then forms uvula. (o palate

formed by intermax segment extends back and joins 2o palate.

?. &ose ! 5ecomes human looking and ma) promin grows towards mandibular.

4. 'ace has neonatal proportions and philtrum of upper lip ! inter ma) process.

N"("L +"V!TY#

(. &asal pits form in the nasal placodes which then forms nasal prominence

*. &asal pits deepen to become nasal sacs ! nasal cavity which grows dorsally.

,. &asal cavity separates from oral cavity by oronasal membrane.

1. @fter = wks oronasal membrane ruptures ! primordial chonchae which is post

to palate.

9. 0hile palate is developing sup" mid" inf chonchae develop. hey are at


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- E)traembryonic mesoderm of yolk sac develop into CIEI&E C@3@ #D(?$

- E)traembryonic mesoderm of conn stalk 5II@ C@3@ #D(4$

- esenchyme of embryo embryonic bld vessels

dorsal and ventral aortae at cephalic region


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"ortic arches = pairs running in branchial arches conn ventral and dorsal aorta on

each side ("*"9 2 disappear

,rd ! 'orms I@

1th ! ft - forms pt of arch of aorta

:t 2 :t subclavian=th ! pulmonary arch branches on both sides develop into lung buds

:t 2 :6@

f 2 6@ and ductus arteriosus

+ON8EN!T"L M"LFOM"T!ON( OF ,E"T "ND 6LD VE((EL(#

Occur in = - 4 children from (";;; newborns.

. Mal&ormations )3 l&t7rt shunt#

O)yg blood" left #aorta$ rt #pulmonary trunk$

- atrial septal de&ect

- ventricular septal de&ect

7 persistent ductus arteriosus

2 Mal&ormations )3 rt7l&t shunt#

6assage of venous blood from rt to lft.

clinically hypo)ia" polyglobulia and asthma

- tetralogy of 'allot ! a comple) of 1 anomalies

($ stenosis of pulmonary artery" *$ ventricular septal defect"

,$ hypertrophy of rt ventricle and 1$ aorta de)troposition.

: Mal&ormations )3out shunts# pulmonary and systemic circulations are separated blood volumes on rt and lft sides eual" group includes

7 aortic valvular stenosis

7 coarctation o& aorta

7 dou*le aortic arch

; "*normalities in heart position 7 de-trocardia - lies on rt side

7 ectopia cordis - on surface of chest

DEVELOPMENT OF E(P!"TOY P"(("8E( "ND L9N8(# 1D2072


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• =k 2;" (? branches formed w/ respiratory *ronchioles.

• ung buds penetrate primitive pleural cavities% #3pace btw parietal and

visceral pleura$

• esoderm cover outer lung visceral pleura%

• 3omatic mesoderm covering inside parietal pleura

During dev endodermal cells thins ! barrier btw bld vessels and air that will fill

lungs at birth is small. Fas 1 periods

(. Pseudo$landular period - lungs resemble $land" all elements formed

e)cept respiratory bronchioles and alveoli. 9-(=wks

*. +analicular period 2 vasculari7ation" respiratory bronchioles developed"

terminal sacs may be seen. 3urvival of fetus is unlikely. (= 2 *= wks

,. Terminal sac period - terminal sacs develop" capillaries contact primitive

alveoli" type I alveolar epith cells differentiate" production o& pulmonary

sur&actant% @fter *4 wks survival of fetus. *=wks till birth

1. "lveolar period 5 diff of terminal sacs alveolar ducts. 5irths -4months.

Mal&ormations o& respiratory system#

• Lun$ a$enesis 7 lun$ *uds &ail to &orm/ unilateral - survival possible.

• espiratory distress syndrome 7 inade?uate production o& sur&actant%

ungs collapse" endodermal damaged. #newborn gags$

• Tracheo7esopha$eal &istula 7 )hen trachea and $ut come into contact 2 is

associated w/ esophageal atresia - blind ending of gut - incidence is (1;;;

births.

DEVELOPMENT OF "L!MENT"Y +"N"L

(tomoduem 5 oropharyngeal membrane

Primitive 8ut 5 'oregut

idgut

Findgut

Proctoduem 5 cloacal membrane

DEVELOPMENT OF P,"YN'# after transformation of branchial arches

develops definite pharyn)

DEVELOPMENT OF E(OP,"89(#

• 'rom pharyn) e)tends caudally

• (st short then rapidly grows from resp diverticulum

• =k cm

• Epithelia and glands form from endoderm

• ells of epithelia prolif and o*literate lumen then re7canali@ed A =kB

• (triated muscle from mesenchyme of lower pharyngeal

(mooth muscle splanchnic mesoderm

DEVELOPMENT OF (TOM"+,#


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• 5egins as dilation o& caudal pt of foregut

• Dorsal side grows much faster than ventral ! g./l. curvature

• =k


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• ystic and hepatic ducts 6!LE D9+T which attaches to ventral duod. 5ut as

duod rotates it becomes on Dorsal side.

• =.2 G *ile production

DEVELOPMENT OF P"N+E"(#

• Develops btw * layers of mesentery

• 2 pancreatic *uds Dorsal appears (st #body + tail$

Central near entry of bile duct duod #head$

• @s stom and duod rotates it pushes pancreas to post )all o& a*domen%

• Dorsal and ventral bud anastomose main pancr duct

• Pro- pt G acc panc duct opens to DD papillae. Distal pt from dorsal bud

• Endodermal cells from caudal foregut tu*ules pancreas acini

• Ends of tubules islets form ! from groups of cells which break off from tub

and lie btw acini.

•

'ibrous sheath and capsule and septa ! splanchnic mesoderm• = . G !N(9L!N secretion *e$ins%

DEVELOPMENT OF T,E (PLEEN#

esodermal origin.

6rimordium forms wks 1-9 w/in mesothelium of dorsal mesentery" behind greater

curvature

'orms from spleen islands" which coalesce spleen

@s stomach rotates" pulls mesentery and so spleen shifted to lft w/. esentery

fuses to dorsal wall of coelom where lft urogenital ridge is developing. @ short

stretch of mesentery


10/13

• esonephric vesicles mesonephric tu*ules" lateral ends continuous w/

mesonephric duct%

• edial end of tubule e)pands 6o)man4s capsule #capilary loops of

glomerulus derive from mesonephric artery$

• apsule w/ glomerulus mesonephric corpuscle%

• ervical and thoracical pts of mesonephros degenerate/ lumbar pt of

mesonephric tubules and mesonephric duct remain.

Me ta nephros #permanent kidney" produce urine in at 0k ((-(,$

Develops 0k 9" * pts

9reteric *ud or metanephric diverticulum 9ETE " pelvis" ma


11/13

Oli$ohydramnios results from failure of urine production.

2% Pelvic kidney 7 located in pelvis" failure of kidney to ascend

:% ,orshoe kidney 7 both kidneys &used at in&erior poles and located in pelvis"

occurs ( per =;; births.

;% Polycystic kidney disease 7 hereditary disease. ontain urine-filled cysts. :esults

from failure of collecting tubules and uriniferous tubules to % Duplication o& ureter and *i&id ureter%

DEVELOPMENT OF !NTEN"L (E'9"L O8"N(

Early genital system till ,rd month indi&&erent sta$e#

!ndi&&erent $onad anla$en

Mesonephric duct remnants o& mesonephric tu*ules

Paramesonephric duct

!ndi&&erent $onad anla$en loc w/in $onadal rid$e #mesenchymal$.

• 8onadal rid$e degenerates" caudal pt $u*ernaculums%

• (e$ment of ridge primordial $erm cells #68s$ #diff at wk =$

• Future $onad .o se- cord.

#coelemic ep thickens and prolif$

Paramesonephric duct develops from

• Invagination of coelomic ep on lateral pt of genital ridge.

• 6ro)imal pt ! coelomic" future peritoneal cavity.

• 3mall pelvis ducts fuse uterova$inal primordium/ elevate sinus

tu*ercle%

DEVELOPMENT OF TE(TE( 1Y chrom

• .o se- cords Testicular cords (N%T #diff in 3ertoli cells.$

#lose conn w/ coelomic epith$

• P8+s spermato$onia

• Mesenchyme interstitial 1Leydi$ cells.

• +ondensation o& mesenchyma Tunica al*u$inae

#lying btw epith and 3&.$

• Descent of testis by 0k 2B peritoneal cavity scrotum.

DEVELOPMENT OF OV"!E( 1lack Y chrom

• .o se- cords degenerate rete ovarii.

• 3uperficial coelomic ep sends off secondary se- cords" diff. &ollicular

cells" w/ 68s primordial ovarian &ollicles%

• Mesenchyma Tunica al*u$inea%

#e)tending btw surf ep and ovarian foll$

• Descent of ovary by =k 2B to small pelvis%


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DEVELOPMENT OF E'T 8EN!T"L!"

!ndi&&erent sta$e

$enital tu*ercle at cranial end of cloacal memb" elongates phallus

uro$enital &olds - paired

la*ioscrotal s)ellin$s - lateral to urogenital folds.

Development o& male $enitalia#

6hallus PEN!(

8 folds fuse and close

abioscrotal swell fuse ! (+OT9M

Development o& &emale $enitalia#

6hallus +L!TO!(

8 folds donGt fuse ! L"6!" M!NO"

abioscrotal swell unfused ! L"6!" M"HO

Efferent ductuli Mesophric tu*ules :egressDuctus epididymidis Mesonephric ducts :egress

Ductus deferens"

E


13/13

,ydrocele - abdominal end of vaginal process remains open" peritoneal fluid passes

into it and forms a hydrocele of testis and spermatic cord.

M al&ormations occurin$ in &e males#

Ectopic ovary - ovary has abnormal location

9terova$inal mal&ormations - result from#($ improper fusion of both paramesonephric ducts

#*$ incomplete development of one paramesonephric duct

#,$ failure of pts of ducts to develop

#1$ incomplete canali7ation of vaginal plate

double uterus

bicornuate uterus

uterus wit! one uterine tube

absence o" uterus

absence o" #agina $ 1%&000 "emales

#aginal atresia ' "ailure o" canali(ation o" #aginal plate

"norectal a$enesis and &istulas - rectum ends above anal canal and is connected to

vagina w/ fistula.

Dev of Eye, Ear, Face, Brain, Heart, Lungs

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