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65 Cards in this Set

  • Front
  • Back
True or False: The Early Cardiovascular System is well developed at the FOURTH week.
What deliever nutrient and O2 rich blood from the placenta to the embryo?
A pair of umbilical veins
________ drain the yolk sac.
Vitelline Veins
________ return venous blood from anterior and posterior parts of the embryo
Cardinal Veins (anterior and posterior)
Where is venous blood discharged in early cardiovasc. system?
into the posterior chamber of the heart known as the Sinus Venosus
Cardinal veins deliver O2 from _____ and ______ parts of the embryo.
Ant and Post
First organ system to become functional and why.
Cardiovasc. System (CVS)
- The embyro is growing so fast that diffusion from placenta to embryo is not sufficient to supply O2 and nutrients...circulation must be established to help carry O2.
In the Early CVS, blood is pumped through a series of __________ into the _________ which distributes blood to the ____ and _____ end of the embryo.
- Aortic arches
- paired dorsal aorti
- cranial and caudal
________ arteries supply posterior segments of the body
In the caudal region, a pair of ________ distribute blood back to placenta for reoxygenation.
umbilical arteries
The heart appears at day ____ and begins to beat at day _______.

The embryo at day 18 is what shape? What comprises this shape?
Flat Disc
- 3 germ layers (ecto, endo, mesoderm)
Germ layer of partic. importance in heart development
The ________ mesoderm, which lies adjeacent to the _______, gives rise to the heart.

In 3rd-4th wk, _______ and _______ are paired, and are found adjacent to the splanch. mesoderm
body cavities and future pericardial cavity
Within the _________, some cells become arranged into longitudinal cords called __________.
Splanchnic Mesoderm

Angioblastic cords
Appearance of _______ is the earliest appearance of the heart.
Angioblastic cords
At day _____, the embryonic disc begins to ________ producing a cylindrical embryo.

fold inward
At day 20, angioblastic cords __________ and form ________.
begin to hollow out

endocardial heart tubes
At day 20, _______ begin to approach each other at the ventral midline. Also, the ______begin to approach each other. Further folding produces fusion of the heart tubes to a ________.
endocardial heart tubes

the halves of the pericardial cavity

single longitudunal vessell
Day 20, _______ bring the endocard. heart tubes and halves of pericardial coelom
lateral folds
At day 22, the _______ are now confluent and surround the ______.
2 halves of pericardial pericardial cavites

primordial heart
At day 22, the single heart tube is suspended by _______.
dorsal mesocardium
At 28 days, the ________ begin to differentiate and the _________ is formed.
- 3 germ layers

- transverse pericardial sinus
At 28 days, the original endocard. heart tubes form the ______, the splanch. mesoderm forms the _______, and the _________ differentiates into the myocardium.
- endocardium
- myocardium
- outermost part of splanch. mesoderm
At 28 days, the _________ breaks down and the ________ becomes continuous above and below the heart - so now the heart is only suspended at its _____ and _____ ends.
- dorsal mesocardium
- paricardial cavity
- cranial and caudal
In adults, the transverse pericardial sinus separates the _________ of the heart from the __________.
- arterial end (pulm. trunk and aorta)
The fusion of the endocardial heart tubes occurs in a _____-to-______ sequence.
5 primitive chambers of the heart from cranial to caudal:
1. sinus venosum
2. primitive atrium
3. prim. ventricle
4. bulbis cordis - just in front of prim. ventricle
5. truncus arteriosus
The _______ and _______ grow faster than the other chambers of the prim. heart causing bending and is referred to as the ______. Such bending brings the ________into a more posterior position
bulbus cordis
prim. vent.
bulboventrtricular loop
two caudal chambers (sinus venosus and atrium)
The bulbis cordis will later form what two major structures?
pulm. trunk
Two simultaneous processes in the 4th and 5th weeks
Atrial and Ventral Septation
What is the atrioventricular valve?
opening b.w prim. atrium and prim. ventricle
Thickenings of tissue on either side of AV canal
ventral and dorsal endocardial cushions
The endocard. cushions grow together and fuse which futher divides the _______.
AVC into rt. and left AVC's
Give the steps of Atrial Septation:
1. Septum primum growns down from roof of primordial atrium creating the border of the ostium primum
2. Ostium primum gets smaller until disappears
3. Complete fusion of sept. primum w/ endocard. cushions
3. Ostium secondundum arises from perforations in ostium primum
4. Forms inside of cranial end of sept. primum.
5. Stops short and doesn't form a complete partition
The septum primum and secondum develop at same/different time?
The septum secondum basically forms the ______
interatrial septum
What does the septum primum do in fetal life?
Moves back and forth allowing blood to cross b/w the atria
HIGH pressure in rt. atrium causes the Sept. Primum to _____.
EQUAL pressure b/w atria causes Sept. Prim. to _____

The _________ is the most caudal chamber
sinus venosus
Left and Rt. horns of sinus venosus are initially _____, then the _______ recieves more blood and enlarges
equal in size

Right Horn
Opening of sinus venosus into atrium shifts from ______ to ______ and will become the ________.
central position
the right

Left horn of sinus venosus will eventually become _____
coronary sinus
Right horn of sinus venosus eventually gets incorporated into the wall of the rt atrium as the ______
sinus venarum (smooth part of wall)
Rough wall part of rt. atrium (pectinate) derives from the _________ before the __________ was incorporated.
Primordial Atrium

Sinus Venosus
What two valves existed where the sinus venosum orginally attached to rt. atrium?
Rt. and left sinuatrial valves.
The rt. sinuatrial valves will become the _______ and the left will become _________.
- crista terminalis

- incorporated into the interatrial septum
The smooth walled part of the left atrium develops from __________, and the rough part arises from ______.
pulmonary vein tissue

primitive atrium itself
The muscular part of the IV septum begins at the _____ and grows _______ towards the ________.
apex of heart
endocard. cushions
Opening b/w the endocard. cushions and muscular septum
IV foramen
Three tissues that grow to fuse IV foramen shut:
1. Left bulbar ridge
2. Rt. bulbar ridge
3. Upgrowth of endocard. cush.
The ________ will form the membranous part of the IV septum
endocard. cushion
Partitioning of the bulbus cordis and truncus arteriosus take place in the ____ and _____ week of development.
5th and 6th
The ridges of the bulbus cordis have a ______ orientation and will slowly grow towards one another turning ________

one chamber into two vessels
Fusion of bulvar ridges creates a septum known as the _______ creating ____ and _____ vessels.
anterior and posterior
Rt. ventricle contribution of the ______ is the conus arteriosus and the left ventricle contribution is the ________.
promximal bulbus cordis

aortic vestibule
Unequal division of bulbus cordis can result in _____ of pulm. trunk or aorta
Misalignment of bulbar ridges in bulbus cordis can result in a ______ defect.
Ventric. septal defect
________ produce chordae tendonae.
cavitation of the walls of ventricles
T/F: conducting system is fully developed at birth
____% of birth defects are cardiac in nature
while of these
2% are _____
8% are _____
and 90% are _______

environmental (viruses, etc.)
Genetic (trisomy 18)
Types of atrial septal defects:
1. Patency of foramen ovale
2. Short septum primum
3. Sept. Secondum can stop short in in its growth
4. Combo of 2 and 3
5. High atrial septal defect (rare)(rt. horn of sinus venosus not properly incorporated into rt. atrium)
Most common ventric. sept. defect is when ____
memb. part of IV septum does not form properly and allows vent.'s to communicate
Embryonic period:

wks 0-8

Wk 9 to term