Development Flashcards
Why does the heart migrate from neck into thorax
because cardiogenic mesoderm migrates to cranial most part of the embryo
What does the heart tube arise from
paired endothelial lined tubes
at what end does the heart tube receive blood and pump blood
receives at the caudal end and pumps at the cranial end
When does cardiac looping begin and what are the 4 dilations
Day 22 bulbus cordis ventricle atrium sinus venosus
When does the heart start beating
Day 22
Why does the heart loop
ventricles grow faster than other regions
Which way does the cranial portion of the heart tube bend
ventrally, caudally and to the right
which way does the caudal portion of the heart tube bend
dorsally, cranially and to the left
What becomes of the sinus venosus
left sinus horn becomes coronary sinus
right sinus horn becomes part of right atrium as sinus venarum
What will the primitive atrium form
left and right auricles
What grows into the left atrium during final steps of development
the pulmonary vein
What is incorporated into the right atrium during final steps of development
sinus venosus
What will the primitive ventricle become
trabeculated portion of left ventricle
What are the 3 parts of the bulbus cordis
caudal, conus cordis and truncus cordis
what becomes of the caudal part of bulbus cordis
trabeculated region of right ventricle
what becomes of the conus cordis part of bulbus cordis
outflow of both ventricles, right= conus arteriosus and left=aortic vestibule
what becomes of the truncus arterioles part of bulbus cordis
pulmonary trunk and aorta
Describe pathway of blood in the developing heart around day 30
blood enters sinus venous-> primitive atrium -> primitive ventricle -> bulbus cordis ->aortic sac -> embryo
What week do coordinated contractions of the fetal heart begin
week 4
What is the first step of partitioning of the atrium
septum primum forms, day 30
What is the second step in partitioning of the atrium
ostium primum forms, day 30
what is the third step in partitioning of the atrium
ostium primum closes, day 33
What is the fourth step in partitioning of the atrium
ostium secundum opens via apoptosis, day 33
What is the fifth step in partitioning of the atrium
septum secundum forms, day 33
what is the sixth step in partitioning of the atrium
foramen ovale forms, because septum secundum is incomplete
What is the original septum primum known as in a newborn
the valve of foramen ovale
prenatally where is the pressure greatest in the heart
on the right side
postnatally where is the pressure gradient of the heart
on the left side
The heart valves form from what tissue type
neural crest cells, endocardial cushions
Why is the right ventricle not in contact with the atria like the left in development
bulboventricular flange regresses during week 5
What are the 2 portions of the interventricular septum. state their origins
muscular portion from mm of ventricle and membranous portion from endocardial cushions
When does partitioning of the ventricles take place
week 7
where are the conotruncal ridges derived form that form pulm trunk and aorta
neral crest cells
how many degress of spiraling do the conotruncal ridges undergo
180 degrees
what is the aorticopulmonary septum
spiraled conotruncal ridges
what does the conus cordis form
conus arteriosus and aortic vestibule aka right and left ventricles
what does the truncus arteriosus form
pulmonary trunk and ascending aorta
where do the semilunar valves form from
neural crest of conotruncal ridges
Ventricular septal defects account for what percent of congenital heart defects
30%
what are the 2 types of ventricular defect and which is most common
membranous- msot common
and muscular
the severity of a ventricular septal defect reflects what, and what is the usual result
size of defect and results in left to right blood shunting
Atrial septal defects account for what percent of congenital heart defects
10%
What are the various types of atrial SD
ostium secundum is too big
ostium primum- endocardial defect
common atrium- no atrial septum
what is the often result of ASDs
left to right blood shunting
What is the result of underdeveloped endocardial cushions
persitent atriocentricular canal
ostium primum defect
membranous interventricular septum defect
What percentage of congenital heart defects are Pulmonary and aortic valave stenosis
pulmonary- 7%
aortic 6%
What additional condition is likely with pulmonary and aortic valve stenosis
patent foramen ovale and ductus arteriosus
What causes tetralogy of fallot
unequal division of truncus arteriosus by conotruncal ridges
what are the 4 components of tetralogy of fallot
overriding aorta
pulmonary stenosis
ventricle septal defect
right ventricular hypertrophy
What causes transposition of Great vessels
conotruncal ridges fail to spiral