embryo circulatory and respiratory system + heart development

Question 1

what is the primitive heart made out of?

Answer 1

endocardial tubes that are made with endothelium

Question 2

describe the steps of heart development

Answer 2

day 20
- endocardial tubes are formed

day 21
- primitive heart tube is formed

day 22
- the 4 main dilations of the primitive heart tube are made

day 23-24
- primitive heart bends because of growth

day 28
- orientation of atria and ventricles to the adult position
- sinuous venosus = part of the right artia and SA node of heart

Question 3

Heart structure and region of primitive heart tube it originated from:

Answer 3

Sinus venosus - SA node and part of right atrium

Atrium - left atrium and part of right

Ventricle - most of left ventricle

Bulbus cordis - most of right ventricle

Question 4

what happens at day 46-50 of heart developmemt

Answer 4

blood flows through the foramen ovale bypassing the lungs

• stays this way till birth

Question 5

what is the foramen ovale

Answer 5

a hole in septum between the right and left atria

Question 6

what is the ductus venosus

Answer 6

allows for the liver filtering step to be skipped because its just been filtered by the placenta

Question 7

after birth what happens to the formen ovale

Answer 7

Once foramen ovale closes –> becomes indentation in septum = fossa ovalis