Embryo- Heart Development

Question 1

heart and great vessel development begins when?

Answer 1

week 3

Question 2

heart development begins development with what layer?

Answer 2

cardiogenic mesoderm

Question 3

location of cardiogenic mesoderm

Answer 3

cranial and lateral to oropharyngeal membrane

Question 4

when does horse-shoe shaped endothelial cord canalize?

Answer 4

week 4

Question 5

primordial heart tube formed by what type of folding?

Answer 5

lateral body folding

Question 6

transverse pericardial sinus forms with what action?

Answer 6

degeneration of dorsal mesocardium

Question 7

bulbus cordis is composed of:

Answer 7

truncus arteriosus

conus cordis

Question 8

conus cordis function

Answer 8

outflow tract of ventricles
forms R ventricle
caudal portion of bulbus cordis

Question 9

conus cordis forms the:

Answer 9

R ventricle

Question 10

primordial atria go on to become

Answer 10

R and L auricles

Question 11

sinus venosus goes on to become

Answer 11

coronary sinus

sinus venarum

Question 12

truncus arteriosus is composed of:

Answer 12

pulmonary trunk and aorta

Question 13

direction of heart folding of cranial end

Answer 13

ventral, caudal, to the right

Question 14

direction of heart folding caudal end

Answer 14

dorsal, superior

Question 15

heart tube formation occurs from

Answer 15

days 18-22

Question 16

cardiac loop formation occurs from

Answer 16

days 22-28

Question 17

partitioning of the heart occurs from

Answer 17

week 4-7

Question 18

endocardial cushions

Answer 18

endothelial cells near AV junction revert to mesenchymal state, invade cardiac jelly, proliferate

Question 19

how are dorsal and ventral walls of AV canal formed?

Answer 19

endocardial cushions push and bulge out into AV canal forming walls

Question 20

formation of AV septum

Answer 20

dorsal and ventral endocardial cushions fuse

Question 21

AV septum divides:

Answer 21

AV canal into R and L

Question 22

what two septa fuse to form interatrial septa?

Answer 22

septum primum

septum secundum

Question 23

from where does septum primum develop?

Answer 23

roof of primordial atrium

moon shaped membrane

Question 24

formation of foramen primum

Answer 24

septum primum grows inferiorly to fuse with endocardial cushions - space between inf. septum primum and endocardial cushion

Question 25

formation of foramen secundum

Answer 25

foramen primum eventually closes off and holes form in septum primum (apoptosis) and holes join to make this

Question 26

formation of septum secundum

Answer 26

as holes in septum primum coalesce to make foramen secundum, this develops from roof of primordial atrium slightly R of septum primum

Question 27

formation of foramen ovale

Answer 27

formed when septum secundum grows inferiorly and develops an opening

Question 28

how does blood pass from R to L atrium?

Answer 28

f. ovale and foramen secundum

Question 29

before birth, ________ atrium has lower pressure and _________ atrium has higher pressure

Answer 29

L lower | R higher

Question 30

acts as a valve for foramen ovale

Answer 30

septum primum

Question 31

how does foramen ovale close?

Answer 31

after birth LA pressure > RA pressure pushes valve closed against septum secundum the two valves fuse = close foramen ovale

Question 32

fossa ovalis

Answer 32

depression in wall of R atrium after closure of foramen ovale

Question 33

interventricular foramen

Answer 33

opening between R and L ventricles

Question 34

formation of IV foramen

Answer 34

muscular part of IV septum grows cranially toward AV septum (does not fuse)

Question 35

from where is membranous IV septum derived?

Answer 35

endocardial cushion tissue mesenchyme

Question 36

most common congenital heart defect

Answer 36

Ventricular Septal Defect (VSD) failure of IV septum to completely form membranous > muscle

Question 37

Tetralogy of Fallot

Answer 37

INTERventricular septal defect Hypertrophy of RV Overriding aorta Pulmonary stenosis

Question 38

how does TOF occur?

Answer 38

aorticopulmonary septum divides outflow tract unevenly = pulmonary stenosis, overriding aorta

Question 39

When does sinus venosus development occur?

Answer 39

7-8 weeks

Question 40

what 3 paired veins drain into sinus venosus?

Answer 40

Vitelline v. Common Cardinal v. Umbilical v.

Question 41

where does sinus venosus usually open?

Answer 41

directly into central dorsal wall of primordial atrium

Question 42

order sinus venosus veins from medial to lateral

Answer 42

vitelline -> umbilical -> common cardinal

Question 43

what happens to sinus venosus?

Answer 43

opening into primordial atrium shifts to R -> formation of opening to future RA

Question 44

R horn of sinus venosus becomes

Answer 44

RA sinus venarum

Question 45

crista terminalis

Answer 45

end of rough part (pectinate m) in wall of RA | transition point to sinus venarum

Question 46

left horn of sinus venosus becomes

Answer 46

coronary sinus

Question 47

coronary sinus drains into

Answer 47

right atrium

Question 48

smooth part of L atrium formed from

Answer 48

absorption of primordial pulmonary vein tissue

Question 49

aortic sac becomes

Answer 49

ascending aorta

Question 50

truncus arteriosus becomes

Answer 50

roots/prox aorta and pulmonary trunk

Question 51

conus cordis becomes

Answer 51

outflow tract of ventricles

Question 52

proximal bulbus cordis becomes

Answer 52

right ventricle

Question 53

primordial ventricle becomes

Answer 53

left ventricle

Question 54

primordial atrium becomes

Answer 54

L/R auricles and trabeculated parts of atria

Question 55

R horn of sinus venosus becomes

Answer 55

sinus venarum of R atrium

Question 56

L horn of sinus venosus becomes

Answer 56

coronary sinus

Question 57

primordial pulmonary v. and brs. become

Answer 57

smooth wall part of left atria

Question 58

first sign of heart formation

Answer 58

horse-shoe shaped endothelial cord forms in cardiogenic mesoderm