embryology of the heart

Question 1

what is gastrulation

Answer 1

mass movement and invagination of the blastula to form 3 laters; ectoderm, mesoderm, endoderm

Question 2

what does the ectoderm form

Answer 2

skin, nervous system, neural crest

Question 3

what does the mesoderm form

Answer 3

muscle, kidneys, blood

Question 4

what does the endoderm form

Answer 4

GI tract, liver, pancreas, endocrine organs

Question 5

what does most of the CV system originate from

Answer 5

mesoderm, some contribution from cardiac neural crest cells from the ectoderm

Question 6

stages of cardiac formation

Answer 6

formation of primitive heart tube, cardiac looping, cardiac septation

Question 7

what day does each stage of cardiac formation occur (first 2)

Answer 7

1. primitive heart tube formation - day 19

2. cardiac looping - day 22

Question 8

what day does the heart begin to beat

Answer 8

22

Question 9

describe formation of primitive heart tube

Answer 9

two endocardial tubes form and then fuse to form one tube

Question 10

what ensures that the heart has a left ward ventricle/ rotates the correct way?

Answer 10

the node secretes nodal which circulates to the left due to the ciliary movement, a cascade of transcription factors transduce looping

Question 11

describe cardiac looping

Answer 11

heart tube begins to bend and fold - primitive ventricle moves left and primitive atria move superiorly. - node secrets nodal - ciliary movement wafts it left. cascade of TF induces looping. ventricle left.

Question 12

describe cardiac septation

Answer 12

endocardial cushions form on dorsal and ventral walls of AV canal and invaded by mesenchymal cells. cushions approach each other and fuse dividing the AV canal into right and left AV canals- partially separate primordial atrium from ventricle. forms outflow tracts and

Question 13

first heart field is

Answer 13

future left ventricle

Question 14

second heart field

Answer 14

outflow tract, future right ventricle, atria

Question 15

what does FHF and SHF create

Answer 15

FHF creates a scaffold which is added to by the SHF and cardiac neural crests

Question 16

what cells invade in cardiac septation

Answer 16

mesenchymal cells

Question 17

what forms when endocardial cushions approach each other and fuse

Answer 17

divides av canal into right and left av canals partially separating primordial atrium form ventricle

Question 18

what forms future left ventricle

Answer 18

first heart field

Question 19

what forms outflow tract future right ventricle and atria

Answer 19

second heart field

Question 20

what stage is node secreted and where from

Answer 20

in cardiac looping from nodal

Question 21

why is node secreted

Answer 21

circulates to the left due to ciliary movement and a cascade of transcription factors induce looping ensuring ventricle is left