CVS- Embrology and Anatomy

8/3/2019 CVS- Embrology and Anatomy

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Cardiovascular SystemEmbryology and Anatomy*

Dr. Kalpana MallaMBBS MD (Pediatrics)Manipal Teaching Hospital

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Embryonic Heart Development

The heart develops in the embryo duringpost-conception weeks 3 - 8


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Beginning Development

Early week post-conception: 2 endothelial tubesMid-week : endothelial tubes fuse to form atubular structure28 days following conception: the single-chambered heart begins to pump blood


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W eek 4

Heart has: single outflow tract, the truncus arteriosus (divides to

form aorta & pulmonary veins)

Single inflow tract, the sinus venosus (divides to formthe superior and inferior vena cavae)

Single atrium Single ventricle

AV canal begins to close


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W eeks 5

W eek 5AV canal closure complete

Formation of atrial and ventricular septumsHeart grow rapidly, and fold back on itself to form its completed anatomic shape


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W eek 7

Ventricular septum fully developed

Coronary Sinus formsOutflow tracts (aorta & pulmonary truck)fully separated


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8 W eeks After Conception

By the end of the 8th week after conception thefetus has a fully developed 4-chambered heart


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L ayers of Heart

Pericardium (most superficial) Visceral, parietal

Myocardium (middle layer) Cardiac muscle

Endocardium (inner)

EndotheliumLines the heartCreates the valves


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R ight Heart Chambers

R ight Atrium (most of base of heart) IVC, SVC, Coronary sinus R t atrium

Ventral wall = rough Pectinate muscle Fossa Ovalis - on interatrial septum, remnant

of Foramen Ovale


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R ight Heart Chambers

R ight Ventricle R A TV R V Pulmonary Valve- pulmonary trunk

- lungs

Trabeculae Carnae muscle ridges along ventralsurface

Papillary Muscle -cone-shaped muscle to whichchordae tendinae are anchored

Moderator Band- muscular band connecting anterior papillary muscle to interventricular septum


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Left Heart Chambers

Left Atrium

Lungs - 4 Pulmonary Veins LA Pectinate Muscles line only auricle


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Left Heart Chambers

Left Ventricle (apex of heart) LA mitral valve LV AV aorta body

Same structures asR

t Ventricle: Trabeculaecarnae, Papillary muscles, Chordae tendinae No Moderator Band


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Heart Valves - heart sounds


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Heart Valves: Lub*-Dub

Tricuspid Valve: R ight AV valve 3 Cusps (flaps) - anchored in R t. Ventricle by

Chordae Tendinae Chordae Tendinae prevent inversion of cusps

into atrium Closure of AV valve 1 st heart sound


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Bicuspid (Mitral) Valve: L eft AV valve

2 cusps anchored in Left Ventricle by chordaetendinae Functions same as R t. AV valve


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**S emilunar valves :Pulmonary Semilunar Valve: R V toPulmonary Trunk Aortic Semilunar Valve: LV to Aorta 3 cusps

Closure of SV 2 nd heart sound


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The Great Vessels and major

branches Aorta (from Left Ventricle)Ascending Coronary arteriesAortic Arch Brachiocephalic trunk Left Common Carotid

Left SubclavianDescending (Thoracic/Abdominal ) Many small branches to organs


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The Great Vessels

Pulmonary veins- 4 into heart (lt atrium)

Pulmonary Trunk (from R t Ventricle)- -2 Pulmonary Arteries into lungs

Inferior/ S uperior Vena Cava / Coronarysinus


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Flow of BloodDeoxygenated - SVC+IVC, Coronary Sinus -enters R A - Tricuspid Valve - R V - PulmonaryValve - Pulmonary trunk Pulmonary Arteries

lungs

Oxygenated blood - 4 P Veins - LA -Bicuspid/Mitral Valve LV Aortic Valve - Aorta

- body


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The Normal Heart


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Circulation

Coronary circulation the circulation of blood within the heart

Pulmonary circulation the flow of bloodbetween the heart and lungsSystemic circulation the flow of bloodbetween the heart and the cells of thebody


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Fetal Circulation: main differences

1. Presence of placental circulation2. Presence of ductus venosus UV to IVC

3. Absence of gas exchange in collapsedlungs

4. W idely open foramen ovale

5. W idely open ductus arteriosus


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Three Shunts of Fetal Circulation

Ductus Venosus ( L igamentum venosum)- Oxygenated blood from placenta - fetal UV -

IVC R A - by passes liver Foramen Ovale

- From R A to LA by passes the R V,Pulmonarytrunk - no blood to lungs

Ductus Arteriosus Blood from pulmonary trunk to aortic arch by passing lungs


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Fetal Circulation

Umbilical Vessels:

-2 Umbilical Arteries ( Medial Umbilical L igaments)=deoxygenated blood from fetus to placenta 1 Umbilical Vein ( L igamentum teres )= Oxygenated

blood to fetus from placenta


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Fetal Circulation

Placenta - umbilical vein - ductus venosus IVC RA- foramen ovale LA LV Aorta systemic circulation

R A R V pulmonary trunk - ductusarteriosus aortic arch - enter the systemic

circulation, by passing the pulmonarycirculation


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Fetal circulation before birth

Note :oxygenated blood mixes with deoxygenatedblood in

(I) Liver (II) IVC(III) rt. Atrium(IV)Lt. Atrium

(V) entrance of the ductus arteriosus into the descendingaorta


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After Birth

Lungs expands with air and pulmonary vascular resistance falls. Pulmonary blood flow increasesThe foramen ovale and ductus venosus closeduring the first day of lifeThe ductus arteriosus close during the first 24 72

hours of life


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CVS- Embrology and Anatomy

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