Heart development

Question 1

where are the cardiac progenitor cells derived from?

Answer 1

intra-embryonic mesoderm

splanchopleuric

Question 2

what forms in the splanchnic mesoderm?

Answer 2

a horseshoe shape develops as the cariogenic region

on either side of the neural plate

Question 3

what happens on day 19?

Answer 3

the endocardial tubes begin to develop on each side and grow

Question 4

what happens to the two endocardial tubes?

Answer 4

lateral folding results in the merging of the two tubes to form the primitive heart

pushed into the thoracic cavity

Question 5

five distinct regions of primitive heart tube from head to tail

Answer 5

trunks arteriosus, conus cordis, primitive ventricle, primitive atrium and sinus venosus

Question 6

what will the truncus arteriosus form?

Answer 6

aorta and pulmonary artery

Question 7

bulbus cordis structures

Answer 7

right ventricle

Question 8

primitive ventricle will form

Answer 8

the left ventricle

Question 9

primitive atrium will form

Answer 9

front parts of the left and right atria

Question 10

what will the sinus venous form?

Answer 10

posterior part of the right atrium, SAN and coronary sinus

Question 11

at what day does the heart begin contracting ?

Answer 11

22

Question 12

where does the blood pump?

Answer 12

initially all venous blood moves into the sinus venous and then to the truncus arteriosus

Question 13

how does the heart tube position change?

Answer 13

1. begins in the cariogenic area in front of the oropharyngeal membrane and neural plate
2. growth of brain pushes the heart into the chest

Question 14

what keeps the heart in the right position?

Answer 14

mesodermal tissue fold called the dorsal mesoderm

Question 15

initial tissues of gut tube

Answer 15

myocardium thickens and secretes a thick layer of rich extracellular matrix called cardiac jelly which separates the endothelium

mesothelial cells from pericardium migrate to form the epicardium

heart tube formed with inner endocardium lining and outer myocardial epicardium

Question 16

what happens at day 23?

Answer 16

cardiac looping begins

Question 17

explain looping

Answer 17

bulbs cordis moves ventrally and caudally and to the right

primitive ventricle moves dorsally, cranially and to the left

Question 18

what happens to the atria?

Answer 18

left sinus horn recedes to form coronary sinus into the right atria

enlarged right sinus horn is absorbed by the growing right atrium and eventually forms part of the inferior vena cava

left atria combine with pulmonary veins

Question 19

what forms the aortal arch arteries?

Answer 19

branchial arch blood vessels

Question 20

which arches form the aorta?

Answer 20

3,4 and 6

Question 21

aortic arches definition

Answer 21

six paired embryological vascular structures that give rise to the great arteries of the neck and head

ventral to the dorsal aorta

Question 22

different parts of the aorta + what form it

Answer 22

ascending- truncus arteriosios

arch- ventral aorta

dorsal aortae- descending aorta

Question 23

what does the first heart field form?

Answer 23

everything below the truncus arteriosus

Question 24

what does the second heart field form?

Answer 24

truncus arterioosis, left ventricle

Question 25

what process occurs next?

Answer 25

septation of right and left channels

Question 26

what tissue is formed?

Answer 26

cushion tissue

Question 27

explain formation of cushion tissue

Answer 27

1. endocardium balloons, due to cardiac jelly secretion 2. endocardium undergoes EMT and enters the ECM 3. superior and inferior cushions fuse, separating the left and right atrioventricular canals

Question 28

what does the endocardial cushion form?

Answer 28

tricuspid valve, mitral valve, part of atrial septum, part of ventricular septum

Question 29

how many holes in primitive atria?

Answer 29

3

Question 30

explain septation of atria

Answer 30

1. septum premium forms and extends down towards the fused cushions, splitting the atrium into two 2. ostium primum is a hole present between the cushion and septum premium that remains before complete cushion 3. ostium secundum forms in the septum primum before premium's fashion 4. septum secundum grows with a hole called the foramen ovale

Question 31

what does the ostium secundum and foramen ovale allow?

Answer 31

shunt going from right to left

Question 32

difference in structure of septum secundum and primum

Answer 32

primum- thinner secundum- thicker more msucular

Question 33

what does the foramen ovale form?

Answer 33

fossa ovalis in right atrium

Question 34

where is pressure higher to allow blood to flow?

Answer 34

higher in right than left allows the shunt to keep going

Question 35

separation of ventricles

Answer 35

muscular ventricular septum grows from the base of the heart towards the endocardial cushions sculpted by the blood flowing through the ventricles membranous septum grows from endocardial cushions and fuse in the middle

Question 36

different structures in ventricles and how they're formed

Answer 36

inter ventricular foramina myocardium thickens to form trabeculae

Question 37

formation of outflow tract

Answer 37

the truncus arteriosus contains endocardial cushions that grow towards each other twist and form a spiral septum dividing outflow tract into the left and right sides, aorta and pulmonary artery respectively

Question 38

major birth defect

Answer 38

tetralogy of fallot

Question 39

four defects of tetralogy of fallot

Answer 39

four defects: 1. pulmonary stenosis 2. ventricular septal defect 3. right ventricular hypertrophy 4. overriding aorta

Question 40

what causes the tetralogy of fallot?

Answer 40

unequal growth of aorticopulmonary septsm

Question 41

explain tetralogy of fallot

Answer 41

aorta too large thus steals from pulmonary artery, therefore stenosed prevents ventricular wall closure, thus septal defect increases pressure on right side, thus right ventricle is larger to handle work

Question 42

what happens to the blood that does not pass through the foramen ovale?

Answer 42

1. enters pulmonary trunk which is linked to distal arch of aorta by ductus arteriosus

Question 43

how does blood bypass liver?

Answer 43

ductus venosus shunts umbilical blood directly into vena cava

Question 44

what happens at birth?

Answer 44

intake of air, leads pulmonary resistance to fall pressure in left atrium now higher than right coses foramen ovale- fuses shut by 11 years ductus arteriosus contracts to close after birth

Question 45

structure that remains of ductus arteriosus

Answer 45

ligamento arteiosum

Question 46

prior to separation, where does venous blood prefer to enter

Answer 46

through vitelline, cardinal and umbilical vein into the right sinus horn