development of the heart and great vessels

Question 1

where do the heart tubes develop from

Answer 1

lateral plate mesoderm of the cranial end of the embryonic germ disc

In 4th week , cephalic and lateral fold of embryonic disc results in fusion to form a angle primitive heart tube
Between week 5-8 the primitive heart tube folds , remodels and septates, reustling in separation of pulmonary and systemic circulation

Question 2

two shunts in the development of the heart

Answer 2

foramen ovale

ductus arteriosus

Question 3

what side does the aortic arch normally lie

Answer 3

Right paired dorsal aorta will normally involute so result in left sided aortic arch

Persistence of both primitive arotic results in a vascular ring
Portenilaly constrict both the esophagus and trachea - dysphagia and dyspnoea

Question 4

The sinus venosus is the most caudal of the primitive heart chambers. By the fourth week (DAY21) of development, it receives blood from the three sets of veins; on each side:

Answer 4

anterior and posterior cardinal veins via the common cardinal vein
umbilical vein
vitelline vein

These veins merge on each side to form the sinus horns which enter the sinus venosus. Cephalically, the sinus venosus is in continuity with the primitive common atrium. The communication between the two is the sinuatrial junction. Folding and enlargement of the heart shift the junction cepahlically and to the right.

Question 5

the three veins - umbilical, cardinal and vitelline merge to form the sinus horns. Cephalically the sinus venous is a continuation of what

Answer 5

primitive common atrium

Question 6

cranial to the sinus horns there is the primitive ventricle and the primitive atrium what separates these

Answer 6

atrioventricular sulcus

Question 7

what does the bulbs cortis ( conus cortis ) form - this is created from the bulboventricular sulcus

Answer 7

truncus arteriosus

aorta and pulmonary trunks

Question 8

at day 23 which way does the primitive ventricle move and bulbs cordis respectively

Answer 8

Primitive ventricle displaced to the left

bulbs cordis inferiorly to the right

Question 9

what does the blubus cordis form

Answer 9

primitive right ventricle

Question 10

what does the conus cordis allow

Answer 10

outflow of tracts of left and right ventricles

Question 11

what is dextrocardia

Answer 11

heart points toward the right side of your chest instead of the left

gastrulation

Question 12

what does situs solitus mean

Answer 12

normal position of thoracic and abdominal organs. This means the heart is on the left with the pulmonary atrium on the right and the systemic atrium on the left

Question 13

situs inversus

Answer 13

congenital(present from birth) condition major visceral organs are reversed or mirrored from their normal positions

Question 14

levocardia

Answer 14

heart on norma side of the body

Question 15

what does the sinus venousus from

Answer 15

vena cava receiving blood from the sinus horns

Question 16

From week five onwards, the following veins are obliterated:

right umbilical
left vitelline
left common cardinal

There is shunting of blood to the right and the the right sinus horn enlarges. Consequently, little remains of the the left sinus horn at birth except the coronary sinus and the oblique vein of the left atrium. Conversely, the dominant right horn assumes the role of the sinus venosus. It becomes incorporated into the wall of the right atrium as its smooth part - the sinus venarum at birth.

Answer 16

The entrance of the sinus venosus into the right atrium is flanked by two folds, the right and left venous valves. Their edges fuse superiorly to form the septum spurium. When fusion of the right horn occurs, the left valve and the septum spurium fuse with the atrial septum. The inferior part of the right valve produces two structures in the mature heart: the valves at the orifice of the inferior vena cava and the orifice of the coronary sinus. The superior part forms the crista terminalis

Umbilical and left vitelline veins obliterate and left cardinal - right sinus horn enlarges and becomes incorporated into atrium( interception) to form smooth wall part called sinus vineerium - opening of the vena cava
Left sinus horn remains small and forms oblique vein of the left atrium and coronary sinus

Question 17

where do the primitive pulmonary veins develop from

Answer 17

left atrium

Question 18

Border between right atrium and smooth muscle part is demarcated by ridge called

Answer 18

cristis terminalis

Question 19

at the end of the 4th week 4 endocardial cushions from dividing atrioventricular canal into right and left atrioventricular orifices from the basis for separation of what two systems

Answer 19

pulmonary and systemic

Question 20

high pressure In what atrium closes the foramen ovale

Answer 20

Higher pressure in the left atrium resulting from increased pulmonary venous flow from the lungs causes the septum primum of the interatrial septum to close the opening. Over time, the tissue will seal the foramen and become the fossa ovalis.

Question 21

a patent foramen ovale occurs to failure of fusion of primum and secundum atrial septa leading to flap valve opening
this shunt normally when right atrial pressure exceeds left atrial pressure
what could be a possible consequence ?

Answer 21

paradoxical embolus

Question 22

atrial septal defect is a deficiency in atrial septum resulting in failure of overlap (hole in the atrial septum) - continuous left to right shunting what problems could this cause

Answer 22

volume loading in right here may increase pulmonary artery pressure and promote arrhythmia.

Question 23

when does formation the ventricular septum start

Answer 23

end of week 4

muscular interventicualr septum forms closing the foramen

Question 24

ventriculospetal defect VSD can occur due to failure of formation which is normally diagnosed in children

Answer 24

true

Question 25

when do the outflow tracts normally form

Answer 25

at week 5

Question 26

failure of formation of the conotruncal septa result in persistent truncus arterioles - single blood vessel what does this present as

Answer 26

deoxygenated blood
cyanosis in 24hr in babies

At brith pulmonary vascular resistance falls and blood circulates through the lungs
The patents ductus arteriosus normally close forming the ligamentum arteriosum and fossa ovalis respectively

Question 27

patent ductus arteriosus more common in which gender

Answer 27

females