CVS: heart field, heart tube , cardiac looping Flashcards
Which organ found in human embryo is first organ to function?
heart
heart begins…:
1. beating ?
2. pumping blood by ?
- early as 21st day of development
- day 24-25
heart is an ..1.. organ whose ..2… patterning is established during ..3…
- asymmetrical
- left-right
- gastrulation
most of the CVS is derived from which germ layer ?
lateral plate (splanchnic) /visceral mesoderm
In response to signals from endoderm, ectoderm and midline mesoderm what forms within the lateral (splanchnic) mesoderm at the cranial end of the embryo ?
cardiac primordium , called the cardiac crescent, or first heart field
what do cardiac progenitor cells develop into ?
cardiac myoblasts
What do blood islands undergo to form vascular structures ?
vasculogenesis
first heart field is initially ..1.. shaped and surrounded by ..2…
eventually it will give rise to ..3… and the ..4..
- horsehoe
- cardiac myoblasts
- left ventricle
- atria
what is named the second heart field (SHF) ?
multipotent progenitor cells that have been identified in pharyngeal mesoderm
what does the second heart field give rise to ?
right ventricle & outflow tract (eventually develop into direct blood away from heart e.g. aorta + pulmonary tract)
Primary heart tube consists of a ..1.. tube with ..2.. mesoderm differentiating into ..3.. that will form …4…
- single endocardial
- adjacent
- cardiomyocytes
- myocardium
Developing myocardium deposits a layer of acellular ..1.. matrix, the ..2…, that separates it from the ..3..
- extracellular
- cardiac jelly
- endocardial tube
where is the primary heart tube initially suspended ?
In the developing pericardial cavity by a dorsal mesocardium located beneath the foregut
what is the dorsal mesocardium also known as ?
dorsal mesentery of the heart
What happens to the heart when the dorsal mesocardium ruptures over almost the entire length of the heart tube ?
the heart is left suspended in the pericardial cavity by its developing arterial and venous poles,
whilst the ruptured dorsal mesocardium becomes the transverse pericardial sinus within the pericardial sac of the definitive heart
what happens to the ruptured dorsal mesocardium when the dorsal mesocardium ruptures over almost the entire length of the heart tube and the heart is left suspended in the pericardial cavity ?
it becomes the transverse pericardial sinus within the pericardial sac of the definitive sac
heart tube wall consists of ?
- endocardium
- cardiac jelly
- myocardium
- epicardium
What are the regions of the primary heart tube ?
Arterial end -> venous end
Arterial end -> venous end
1. aortic roots
2. Truncus arteriosus
3. conus cordis
4. proximal 1/3
5. primitive ventricle
6. primitive atrium
7. sinus venosus
Bulbus cordis consists of what ?
- truncus arteriosus
- conus cordis
- proximal 1/3
sinus venosus develops into ?
posterior portion of the right atrium, the SA node and the coronary sinus
primitive atrium develops into ?
trabeculated parts of right and left atria
primitive ventricle develops into ?
trabeculated part of left ventricle
bulbus cordis develops into ?
- trabeculated part of right ventricle
- outflow part of both ventricles (distal part)
truncus arteriosus divides and gives rise to … ?
ascending aorta and pulmonary trunk
where is bulboventricular sulcus (interventricular septum) found in the primary heart tube ?
between the proximal 1/3 of bulbus cordis and primitive ventricle
what happens day 23 (week 4) to the primary heart tube ?
it begins to elongate and simultaneously bend and twist into a C-shaped structure
with the bend extending towards the right side: the ventral surface of the primary heart tube forms forms the right outer curvature of the C-shaped heart
when does the heart tube take the S-shaped configuration ?
it continues to elongate at both arterial and venous poles
In process of heart tube taking S-shaped configuration what happens ? to the following:
1. primitive right ventricle
2. primitive left ventricle
3. primitive atrium
- displaced caudally, ventrally and to the right
- displaced to the left
- it acquires a more dorsal and cranial position
What is the end result of cardiac looping ?
to bring the 4 presumptive chambers of the future heart into their correct special relationship:
* atrium -> dorsal & cranial
* ventricle -> displaced left
* bulbus cordis -> moves inferiorly , ventrally to the right
by which day is the elongation of the heart tube is complete ?
28
what does the atrioventricular junction develop into ?
atrioventricular canal which connects the primitive atrium and the primitive ventricle
what develops into the primary interventricular foramen ?
bulboventricular sulcus between the ventricle and bulbus cordis
Name 3 abnormalities associated with cardiac looping
- ventricular inversion
- heterotaxy
- visceroatrial heterotaxy syndroms
ventricular inversion is a condition in which …?
looping of the heart tube is reversed from its normal sinistral (left) pattern
what does ventricular inversion result in ?
a heart that has its apex inferior to the right side (rather than the left)
what is heterotaxy as a condition ?
a congenital condition ascribed to abnormal left-right axis formation
2 froms of heterotaxy ?
partial situs ambiguous and situs inversus totalis
- partial situs ambiguous (a verseral of some organs)
- or situs inversus totalis (reversal of all visceral)
- a few if any symptims
what are visceroatrial heterotaxy syndromes ?
conditions where the abdominal viscera and the atrial pole are oriented on opposing sides of the body
What structural defects are associated with visceroatrial heterotaxy syndromes?
- A common atrium
- Malalignment of the atrioventricular canal and outflow tract
- Abnormal venous and arterial vascular connections
