Key concepts: Heart Development

Question 1

what is seen from superior view of the embryo

Answer 1

cranial aspect
caudal aspect

Question 2

cranial aspect

Answer 2

thickening of the mesoderm infront of the pro caudal plate

Question 3

what does the heart tube develop from

Answer 3

the splanchnic layer of the lateral plate mesoderm

Question 4

what does the endoderm release

Answer 4

vascular endothelial growth factors
VEGF’s

Question 5

function of VEGF’s

Answer 5

stimulates the differentiation of the lateral plate mesoderm
outer and inner core

Question 6

outer core

Answer 6

angioblast cells
form blood vessels and heart tube

Question 7

inner core

Answer 7

hemocytoblast
form blood cells

Question 8

heart tube and pericardial cavities from 2 to 1

Answer 8

lateral folding occurs
layers fuse
form one of each

Question 9

what is the dorsal mesocardium

Answer 9

connects th pericardial cavity to the heart tube

Question 10

layers of the heart tube from outside to inside

Answer 10

endocardium
cardiac jelly
myocardium

Question 11

endocardium

Answer 11

made from angioblasts

Question 12

cardiac jelly

Answer 12

made from myocardium secretion

Question 13

myocardium

Answer 13

made from the cardiac monocytes

Question 14

what occurs during cranial caudal folding

Answer 14

the heart moves into the cranial cavity
and the heart tube into the pericardial cavity

Question 15

label the heart tube top to bottom

Answer 15

aortic sac
truncu arteriosus
bulbos cordis
primitive ventricles
primitive atria
sinus venosus

Question 16

aortic sac

Answer 16

leaves via the dorsal aortae

Question 17

trunks arteriosus

Answer 17

becomes the pulmonary trunk and the ascending aorta

Question 18

bulbs cordis

Answer 18

right ventricles
right and left ventricular outflow tracts

Question 19

primitive ventricle

Answer 19

left ventricle

Question 20

primitive atria

Answer 20

left and right atrium

Question 21

sinus venosus

Answer 21

have left and right horns
and 3 veins entering

Question 22

label the veins entering the sinus venosus from lateral to medial

Answer 22

common cardinal
umbilical
viterline

Question 23

heart formation

Answer 23

cardiac looping
AV canal formation
separating primtive atria
separate the BC and PV
inflow tracts
forming outflow tracts
semi-lunar valve formation

Question 24

importance of cardiac looping

Answer 24

dependent on dyneins
if absent then the heart will bend left and not right

Question 25

process of cardiac looping

Answer 25

TA and BC move down and to the right
PA moves to the left of the midline as TA and BC continue their movement
PA moves backwards and upwards
PA now up either side of the TA, attached to SV below the BC
SV allows cells to move into pericardial cavity and forms visceral pericardium
SV also allows cells to move into the “heart” forming the primitive conduction system

Question 26

AV canal formation

Answer 26

AV sulcus between the PV and PA
neural crest cells forming dorsal and ventral endocardial cushions
cushions fuse to form the septum intermedium
2 canals form either side called the right and left AV canals
connected by annulus ring, valve flaps
cordinae tendinae come off
valvulpus apparatus becomes bi and tricuspid

Question 27

separating primitive atria

Answer 27

septum primum tries to reach from the top to the septum intermedium
doesnt reach and forms hole known as ostium primum
septum prinum eventually closes the ostium prinum
another hole develops near the top which is the ostium secundum
more tissue grows to try and block the ostium secundum
there is still a small hole called the foramen ovale which eventually closes when born
some division formed so can classify as right and left atrium

Question 28

separating the BC and PV

Answer 28

at the heart the apex develops muscular portion of interventricular septum
grows into the heart
space between= membranous portion of inter ventricular septum
comes from septum intermedium, closed gap
BC (one part of this) becomes the RV
PV becomes the LV

Question 29

inflow tracts

Answer 29

between the PA and SV
all veins on the left horn of SV break down leaving left horn
umbilical horn degenerates leaving CCV and V
left horn shifts towards right horn and fuses before entering the SV
SV absorbed to become PA
left horn becomes coronary sinus
right common cardinal becomes superior vena cava
right vitelline vein to the inferior vena cava

Question 30

outflow tract formation

Answer 30

neural crest cells form 2 truncal ridges in the TA and 2 bulbar ridges in the BC
also ridge in the middle of TA and BC
2 ridges one is dorsal and the other is ventral
meet in the middle
when ridges approach they spiral around central axis
ridges in the TA fuse to form the septum
ridges in the BC fuse to form septum
ridges in middle form septum
causes corkscrew of TA and BC to form aorticopulmonary septum
as blood moves LV through posterior portion of the septum crosses behind then infront of the top portion to form aortic arch
RV moves anterior, cross then posterior to form pulmonary trunk
structure rotates and splits structures

Question 31

semi lunar valve formation

Answer 31

cross section at the bulbis cordis and conus cordis junction
neural crest cells form endothelial cushions (left right dorsal ventral)
during rotation vagination occurs
splits cushions left and right
then splits entirely into dorsal and ventral
still have full dorsal ventral cushion but half right and left cushion
dorsal= left ventricular outflow tract= aorta
ventral= right VOT= pulmonary trunk
forms semilunar valves
rotation occurs

Question 32

right hand side post rotation

Answer 32

aortic SLV
LVOT