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38 Cards in this Set

  • Front
  • Back
prochordal plate
-region at cephalic end of embryonic disc where ectoderm and endoderm remain in contact (migration of intra-embryonic mesoderm does not separate)
-replaced by the buccopharyngeal membrane (forms temporary seal of oral cavity and in week 4 breaks down to establish communication bt gut tube and amniotic cavity)
sinus venosus
-venous channel that drains blood into the heart from the embryo and the placenta
-initially symmetrical (2 horns)
-in adult it becomes the
1) coronary sinus
2) smooth part of right atrium, and
3) proximal portion of the IVC
septum transversum
unsegmented mesoderm
develops cranial to the prochordal plate
gives rise to:
-part of the diaphram
-the fibrous pericardium
-CT of the liver
migrates from position in cervical region of the embryo to the abdominal/thoracal portion of adult
bulbus cordis
part of heart tube that gives rise to:
-the conus cordis (outflow tract of ventricles) and the
-truncus arteriosus (which forms porximal parts of aorta and pulmonary trunk)
conus cordis
part of developing heart tube comprising outflow tracts, developed from the bulbus cordis and leading to the truncus arteriosus
AV canal
-communication between common atrium and the early ventricle
(initially positioned to the left side of developing heart, must shift to the middle)
endocardial cushions
-mesenchymal structures
-develop in the wall of the AV canal
-superior and inferior cushions on each side fuse to separate the AV canal into right and left openings
- the openings become the tricuspid and mitral valves respectively
conotruncal cusions
-form to separate the outflow tract of the heart (the trunkoconal region) into a pulmonary and aortic trunk
-derive from endothelial cells and neural crest cells that migrate into the cardiac jelly
aorticopulmonary septum
-spiral partition dividing the ascending aorta and the pulmonary trunk
- formed from the fusion of the conotruncal cushions (derived from endothelial and neural crest cells)
cardiac jelly
gelatinous noncellular material between the endothelial lining and the myocardial layer of the heart in very young embryos, later serving as a substratum for cardiac mesenchyme
ductus venosus
-embryonic vessel that lies on the visceral surface of the developing liver
-acts as a bypass thus enabling oxygenated blood in the umbilical vein to gain access to systemic circulation without passing through the liver
ductus arteriosus
embryonic vessel that connects the pulmonary trunk to the arch of the aorta (bypassing the lungs)
septum secundum
second crescent-shaped fold forming part of the developing atrial septum (the other part of the septum is made of the previously devloped septum primum)
ostium secundum
second foramen to form in the upper part of the septum primum which forms the foramen ovale of the atrial septum
septum primum
-sickle-shaped growth in the roof of the common atrium
-extends toward the endocardial cushions leaving the opening of the foramen primum
foramen ovale
hole in the atrial septum (left open after septum secundum forms as flap over most of the osteum secondum) in the embryo and fetus allowing oxygenated placental blood in the right side of the heart to pass to the left w/o going through the pulmonary circulation (normally this hole closes immediately after birth- forming fossa ovalis)
membranous interventricular septum
developed from endocardial cushions- makes up superior part of Interventricular septum
heart forms at what rim of what structure?
anterior trim of embryonic disk
heart forms just (......) to the (......) plate
prechordal plate
angiogenic cell clusters
develop around yolk sac in extraembryonic mesoderm, give rise to channels that extend into the embryo and form initial components of cardiovascular system
from what structures are the embryonic paired heart tubes derived?

where in the embryo do the tubes initally form?
-plexus of vascular channels, fuse to form endo thelially-lined heart tube
-surrounded by splanchnic mesoderm (future VISCERAL PERICARDUM)

-formed initally in the splanchnic/somatic mesoderm, bulge into the intraembryonic coelom
what forms the pericardial cavity
-formed by intraembryonic coelom
-initally this cavity is ventral to heart with a dorsal mesocardium suspending the heart
-eventually breaks down so the percardium surrounds the entire heart
septum transversum- becomes what structure?

where is it found in relation to the developing heart?
beomes the diaphragm
located just inferior to devloping heart
when does the heart begin to beat?
early in the 4th week of development
flow of blood through primative "tube" sheart goes through what structures?
-sinus venosus---
-pimative atria---
-the ventricles and bulbous cordis---
-then the aortic arch vessels---
sinus venosus receives blood from what vessels?
cardinal veins (drain embryo proper)
vitelline veins (from yolk sac and the umbilical veins from the placenta)
cardinal veins
drain embryo proper (drain into sinus venosus)
vitelline veins
drain yolk sac and umbilical veins from the placenta (transverse the liver and drain into sinus venosus)
around day 23 venous end of embryonic heart tube folds in what direction relative to the ventricle?

what shape structure does the heart become?
moves posterior and superior (folding up and over posteriorly to form atria)

heart tube becomes a loop
what stucture is derived from the bulbus cordis?
-becomes the conus cordis and acts as outflow tract for both ventricles to the truncus arteriosus
bulbous cordis
name two parts
outflow tract for the heart tube

conus cordis and truncus arteriosus
where do the auricles come from?
vestiges of the primative atria (rough-walled)
***definitive atria smooth walled, from incorporation of sinus venosus (on right) and the pulmonary veins (on left)
definite aortic arch derived from
the left 4th arch
definitive ductus arteriosus derived from
left 6th arch
allows embryonic circulation to bypass the liver
ductus venosus
allows embryonic circulation to bypass the lungs
ductus arteriosus
foramen ovale
what closes the foramen ovale in most cases?
higher pressure in the LA due to increased venous return from lungs upon first breath
what happens if foramen ovale does not close properly?
forms left to right shunt between atria