Lecture's 6 + 7 - Embryonic development of the heart

Question 1

what is the embryonic cvs called ?

what is the first thing to form

Answer 1

the cardiogenic field

endocardial tubes are joined together by the lateral folding of the embryo to form the primitive heart tube

Question 2

what are the sections of the primitive heart tube ?

Answer 2

Aortic roots
truncus arteriosis
bulbus cordis
primitive ventricle
primitive atrium
sinous venosus

Question 3

what forms from pulmonary veins in development of heart ?

Answer 3

the oblique sinus formed as the left atrium expands to absorb parts of the pulmonary veins

Question 4

what are the three shunts within the primitive hear ?

Draw the path it takes and explain what happens upon birth

Answer 4

ductus arteriousus - passage from pulmonary artery to aorta to bypass the lungs

ducutus venosus - from placneta (oxygen exchange) bypasses liver to enter the hear via the IVC

foramen ovalae - R to L shunt to allow passage from right to left atria - bypass the pulmonary system

Question 5

how are the great vessels derived ?

what additional thing do you need to know ? hint :hook

Answer 5

early embryology we have a symmetrical system of aortic arches, 1234 and 6 - this undergoes remoddeling

4th arch gives rises to - R - Right subclavian artery L gives rise to aortic arch

6th arch gives rise to R- R pukmonary artery L - L pulmonary artery and ducuts arteriosus

larengyal nerves get hooked and pulled down during the process - L hooks as pulmonary artery and ducut arterosis

R- right subclavian artery hooks

Question 6

what occurs in the heart after the looping process ?

Answer 6

we have a atrioventricular canal, need to obtain the two pumps in series config.

so

Atrial septation
Ventricular septation
Septation of the great arteries

all occur simultaneously - to divide the primitive chambers

Question 7

outline the process of atrial septation

Answer 7

1. Septum primum grows down to fused endocardial cushions in the center , there is a hole called the ostium primum
2. Ostium secundum appears in the septum primum
3. ostium primum disappears
4. Crest shaped septum secundum grows
5. the second secudum completes growth and has a hole called the foramen ovalae
6. now have 2 septum with holes, forms a R to L shunt

Question 8

after muscular growth in the ventricular septum what is left, what happens to it ?

Answer 8

the primary ventricular foramen, a membranous ventricular septum forms, from endocardial cushions (derived from neural crest tissue)