Development of Cardiovascular

system

Dr.G.Prabavathy

Assistant Professor

Objectives

Formation of the trilaminar embryo

Origin of cardiogenic cells

Formation of bilateral heart fields

Formation of the heart tube

Folding of the heart tube

Looping of the heart tube

Cardiac developmental abnormalities

Day 0 : Fertilisation forming zygote initiating

embryogenesis

2 cell stage; 4 cell stage; morula

Week 1 : implantation ( as a blastocyst)

Week 2 : bilaminar stage (epiblast,hypoblast)

Week 3 : gastrulation ;primitive streak,notochord

and neural plate begin to form

Week 4: heart begins to form

Cardiovascular system – develops from

mesoderm Specifically,

splanchnic lateral

plate mesoderm

The cardiogenic field is established in the mesoderm just after

gastrulation (~18-19 days) and develops into a fully functional,

multi-chambered heart by the 8th week

angiogenic cell clusters (angioblasts/hemangioblasts)

(right dorsal aorta)

(right endocardial tube)

blood islands (developing blood vessels)

cardiogenic field

pericardial cavity

Langman’s fig 12-1

Cardiogenic area- cranial end between septum

transversum and prochordal plate

• Intraembryonic coelom – pericardial cavity

• Splanchnopleuric mesoderm underneath pericardial

cavity – Primitive heart tube

• Heart tube – endocardium of heart

• Splanchnic mesoderm – myocardium and

Epicardium

After folding

Cardiogenic cords get canalized to form two

endothelial heart tubes

PARTS OF THE HEART TUBE

Arterial end:

• Truncus Arteriosus –

continuous with aortic

sac having right and left

horns

• Each horn – first

pharyngeal arch artery

arises,

- Continuous with

respective dorsal aorta

Venous end:

Sinus venosus

Receives three primitive

veins:

• Vitelline vein – yolk sac

• Umbilical vein –

placenta

• Common cardinal vein –

body wall

EMBRYONIC DILATATION ADULT DERIVATIVES

Truncus arteriosus Ascending Aorta and

Pulmonary trunk.

Bulbus cordis.

.

Smooth part of Right

Smooth part of Left ventricle(aortic

vestibule)

Primitive ventricle

Trabeculated part of Right

ventricle.and Trabeculated part of

Left ventricle

Primitive Atrium Trabeculated part of Right atrium

Left Trabeculated part of atrium

Sinus venosus

Smooth part of Right atrium(sinus

venarum)

coronary sinus

oblique vein of the Left atrium

FATE OF VARIOUS DILATATIONS OF HEART TUBE

• Heart tube lies in the floor of pericardial cavity After head fold, undergoes 180 rotation, heart tube lie on the roof of pericardial cavity

Moore & Persaud fig 13-9

Positioning of Heart tube

in relation to pericardial

cavity

Formation of Cardiac wall

• Endocardium–

endothelial heart tube

• Myocardium-

myoepicardial mantle

• Epicardium-

myoepicardial mantle

External adult form of heart

Cardiac loop

Dorsal mesocardium

Bulboventricular loop

DEXTRO CARDIA

• All the chambers of

the heart and

associated blood

vessels are reversed

as a mirror image

• Heart tube bends to

left

• Associated with situs

inversus

Clinical correlation

ECTOPIA CORDIS

• rare condition in which is

Heart is exposed on the

surface of the Thorax.

• Due to nonunion of two

pieces of developing

sternum.

Single lumen primitive heart tube is partitioned into Four chambers by the formation of four septa:

1.Atrioventricular septum.

2. Interatrial septum.

3. Interventricular septum.

4. Aorticopulmonary septum

Development of various chambers of Heart

Formation of Atrio-ventricular septum

• AV septum divides the AV canal into right and left AV canal

• Two thickenings appear – one on dorsal and one on ventral

wall – endocardial cushions or AV cushions