6 development of heart - 1

8/6/2019 6 Development of Heart - 1

1/38

DEVELOPMENT OF HEART


2/38

Cardiovascularsystem:

Appearsinthe 3rd weekofintrauterinelife

Itisthefirstsystemtostartfunctioningwhen

embryoisnolongerabletosatisfyits

nutritionalrequirementsbydiffusion.

DevelopmentofheartCardiogenicarea- Cranialtoprochordal plate

Fromsplanchnopleuricmesoderm

Startsaround 18thdayofintrauterinelife

Bloodislands uniteandformcardiactubes

Intraembryoniccavityoveritis pericardialcavity.


3/38

BloodIslands Cardiogenicarea


4/38

Pericardial

cavity


5/38

Twoendocardialhearttubes

single primitivehearttube


6/38

Bilateralcardiogeniccordscanalizedtoformthe paired

endocardialhearttubes

2endocardial hearttubesfusetoformasingletube- called

primitivehearttube

Thisfusionstartscranially &extendsincaudaldirection.Theendocardialhearttubeformstheendothelialliningor

endocardium oftheheart

Splanchnopleuricmesoderm coveringthehearttubeforms

myoepicardialmantle whichgivesrisetocardiacmuscles

andviscerallayerofthe pericardium (epicardium)


7/38

Partsofendocardialhearttube

Initiallythehearttubeshowsaseriesofdilatations&

constrictionsresultingin 4 chambers.

Fromcranialtocaudalend

1.Truncusarterious

2. Conus

3. Primitiveventricle

4. Primitiveatrium

5. Sinusvenosus

Bulbuscordis

1

2

3

4

5

Aorticsac

Common

cardinal

vein

Vitelline

vein

Umbilical

vein


8/38

Fusionofhearttubes (22nd day)


9/38

THE HEART TUBE

Theventricleandtheatriumareconnectedbyanarrowatrioventricular canal

Thesinus venosus has

right and left horns

Thebulbus cordis liesatthearterial endoftheheartandisdivisibleintoa proximalconus andadistaltruncusarteriosus

Thesinus venosus liesatthevenous endofthehearttube


10/38

THE HEART TUBE

Thetruncus arteriosus iscontinuousdistallywiththeaorticsacwhichisconnectedtothedorsal aortae bythepharyngealarch arteries

Eachhornofthesinusvenosusreceivesonevitelline vein, oneumbilical vein andonecommon cardinal vein

AsaresultofrapidgrowthofthetubeitbecomesfoldedonitselftoformaUshapedbulboventricular loop

Theatria and the sinusvenosus nowcometolieaboveand behind the ventricle


11/38

Formationofbulboventricularloop


12/38

Diagramaticrepresentationofincorporation

of conusintoventricle


13/38


14/38

Aorticsac

Common

cardinal

vein

Vitelline

vein

Umbilical

vein

Sinusvenosus

Representthevenousendofthe

hearttube

Hasabodyandrightandlefthorns

Eachhornreceives 3 veins

Vitellinevein-fromtheyolksac

Umbilicalvein-fromplacenta

Commoncardinalvein- from

thebodywalloftheembryo

sinus venosus


15/38

Aortic

sac

Common

cardinal

vein

Vitelline

vein

Umbilical

vein

Fateofsinusvenosus

Lefthorn

Receiveslessblood

Retrogresses

Becomesatributaryofrighthorn

Lefthorn- developsintocoronarysinus

Righthorn

Receivesmoreblood

Incorporatedinto primitiveatrium &formssmooth partofright

atrium

Rightcommoncardinalvein- superiorvenacava

Rightvitellinevein- partofinferiorvenacava

sinus venosus


16/38

Fateofprimitiveatrium

Afterabsorptionofthesinusvenosus, theatrialchamberis

partitionedtoformtherightandleftatriabythedevelopment

ofinter-atrialseptum

Interatrialseptum- Septum primumandseptumsecundum

Tillbirththereisgap between2septa- foramenovale

Onlyafterbirththe2septafusetocompletethe partition

Righthalf- Rough partofrightatrium

Lefthalf- Rough partofleftatrium (auricle)


17/38

Fateofprimitiveventricleandbulbuscordis

Conus partofbulbuscordisisabsorbedintothe primitiveventricletoformabulbo-ventricularchamber

Bulbo-ventricularchamber islaterdividedinto2bythe

developmentofinterventricularseptum togiverisetothe

rightandleftventricles.

Interventricularseptum-

Primitiveinter-ventricularseptum

Atrio-ventricularcushion

Spiralseptum


18/38


19/38

Righthalfofconus- Smooth partofrightventricle

Righthalfofprimitiveventricle- rough partofrightventricle

Lefthalfofconus- Smooth partofleftventricle

Lefthalfofprimitiveventricle- rough partofleftventricle

Truncusarterious- Partitionedbyspiralseptumtoformthe

ascendingaortaand pulmonarytrunk.


20/38

Summaryofdevelopmentoftheheart

RightatriumRough part- Primitiveatrium

Sinusvenarum (smooth part)-Absorptionofrighthornof

sinusvenosusInteratrialseptum- Septum primum&Septumsecundum

Leftatrium

Rough part- Primitiveatrium

Smooth part-Absorptionofpulmonaryveins

Interatrialseptum- Septum primum&Septumsecundum


21/38

Summaryofdevelopmentoftheheart

Rightventricle

Inflowing part- Right partofprimitiveventricle

Outflowing part- Right partofconus

Leftventricle

Inflowing part- Left partofprimitiveventricle

Outflowing part- Left partofconus

Developmentofotherassociatedstructures-

Coronarysinus- Lefthornofsinusvenosus& Leftcommon

cardinalvein

ObliqueveinofMarshall- Leftcommoncardinalvein

Inferiorvenacava- Terminal partofrightvitellinevein

Superiorvenacava- Rightanteriorcardinalvein& Right

commoncardinalvein


22/38

Developmentofserous pericardium

Parietallayer- Somatopleuriclayeroflateral platemesodermViscerallayer- Splanchnopleuriclayeroflateral platemesoderm

Transverse pericardialsinus-

Thehearttubeisforsometimesuspendedfromthedorsalwallofthe pericardialcavitybytwolayersofpericardiumcalled

dorsalmesocardium

Thedisappearanceofdorsalmesocardiumresultsintransverse

sinus

Oblique pericardialsinus-

Bytherearrangementsofpulmonaryveins


23/38


24/38


25/38

Atrialandventricularseptum

1. Septum primum

2. Septum secundum3. Pulmonary veins4. Ostium secundum5. Foramen ovale6. Membranous

interventricular septum7. Muscular interventricularseptum8. Endocardial cushions


26/38

Atrial and ventricularseptum

1. Venous valves2. Septum primum

3. Ostium secundum4. Septum secundum5. Pulmonary veins6. Endocardial cushions7. Interventricular foramen

8. Muscular interventricularseptum9. Foramen ovale


27/38

Formationofaorticopulmonary

septum

1. Aorta2. Left pulmonaryartery

3. Pulmonarytrunk4. Muscularinterventricularseptum5. Rightventricle6. Membranousinterventricularseptum


28/38

Developmentofaorticopulmonary

septum

1. Aorticopulmonaryseptum

2. Pulmonaryvalve3. Pulmonaryartery

4. Aorticvalve

5. Aorta


29/38

Formation ofthe atria

1.Superiorvenacava

2. Pulmonaryveins

3. Leftatrium

4. Rightatrium5.Septum primum

6.Septumsecundum

7. Primitiveleftatrium

8. Primitiverightatrium

9. Valveofinferiorvenacava

10. Valveofcoronarysinus11.Sinusvenarum


30/38

Formationoftheventricles

1. Membranousinterventricularseptum

2. Muscularinterventricularseptum

3. Endocardialcushions4. Leftventricle

5. Rightventricle

6. Ventricularwall


31/38

Partitioningoftheatrioventricular

canal

1. Lateralendocardialcushion

2. Ventralendocardialcushion

3. Dorsalendocardialcushion

4. Leftatrioventricularcanal5. Rightatrioventricularcanal

1. Leftatrioventricularcanal

2. Rightatrioventricularcanal

3. Tricuspidvalves

4.Bicuspidvalves


32/38

Anomalies

Dextrocardia-Anomoliesofcardiaclooping

Heartliesontherightsideofthethoraxinsteadofleft.

Situsinversus, acompletereversalofasymmetryinall

organs

Atrialseptaldefect (ASD)orPatentforamenovaleor

ostiumsecundumdefect

A largeopeningbetweentheleftandrightatrium.


33/38

Anomalies

Ventricularseptaldefect (VSD)

Ventricularseptaldefectsmorecommon

Fallotstetralogy: Duetoanunequaldivisionofthe

conus

Has 4 characteristicfeatures

1. Pulmonarystenosis

2. Ventricularseptaldefect

3. Overridingofaorta

4. Hypertrophyofrightventricle


34/38

VSD


35/38

Persistenttruncusarteriosus

Pulmonaryarteryorginatesfromcommontruncus A

FailedseptumformationinthetruncusandconusB

accompaniedby VSD


36/38

Transpositionofgreatvessels&

pulmonaryvalvularatresia


37/38

Aorticvalvularstenosis&atresia


38/38

END OF PART - I

6 development of heart - 1

Documents