Exam #2 Flashcards
The cardinal anastomotic shunt becomes what mature structure? At what week does this shunt appear?
LEFT BRACHIOCEPHALIC VEIN- caudal part of left cardinal degenerates.
- 8th week
p. 191 Moore
What forms the SVC (2)?
Right anterior and right common cardinal
What are the adult derivatives of the posterior cardinal veins (2)?
root of the azygos vein and the common iliac veins.
What are the adult derivatives of the subcardinal vein (4)?
- ) stem of the left renal vein
- ) the suprarenal veins
- ) the gonadal veins (testicular and ovarian)
- ) a segment of the inferior vena cava
p. 192
What are the adult derivatives of the supracardinal veins (cranial (2) and caudal (2) to the kidneys – caudal left and right)?
Cranial: azygos and the hemiazygos veins.
Caudal: the left supracardinal vein degenerates, but the RIGHT supracardinal vein becomes the inferior part of the IVC.
p.192
What are the four main IVC segments and where did they come from?
- ) Hepatic: Proximal part of right vitelline vein.
- ) Prerenal: Subcardinal vein.
- ) Renal: Subcardinal-supracardinal anastomoses.
- ) Postrenal: Right supracardinal vein
Pharyngeal arches form during the ____–____ weeks
4th–5th weeks.
What is the fate of the caudal dorsal aortas?
Fuse to form a single lower thoracic and abdominal aorta.
What is the fate of the cranial pair of dorsal aortas?
Right disappears, left becomes the PRIMATIVE AORTA.
What is the fate of the six aortic arch/pharyngeal arch arteries? (3 has proximal and distal, 4 and 6 have left and right).
1.) Maxillary and external carotid arteries.
2.) Dorsal aspects –Stapedial artery
3.) Proximal aspects –common carotids
Distal aspects – Internal carotids
4.) Left – Part of aortic arch. Right – right subclavian (proximal segment).
5.) Nothing
6.) Left –Proximal: proximal left pulmonary artery. Distal: Pre-natal shunt, ductus arteriosus.
Right –Proximal: Proximal right pulmonary artery.
Distal: Nothing.
What is the precursor to the common iliac arteries?
Fifth lumbar pair of intersegmental arteries.
What is the fate of the intersegmental arteries of the neck?
Join together to form the vertebral artery.
What is the fate of the intersegmental arteries of the thorax?
Intercostal arteries
The vitelline arteries supply the _______ and, later, the primordial _________, which forms from the incorporated part of the _______.
- umbilical vesicle
- primordial gut
- umbilical vesicle
p. 194
What is the fate of the three vitelline arteries that persist and what do they supply?
- ) Celiac arterial trunk to foregut
- ) Superior mesenteric to the midgut
- ) Inferior mesenteric to the hindgut
What is the fate of the umbilical arteries that persist and what do they supply?
- Proximal portions as the INTERNAL ILIAC and VESICAL ARTERIES.
- Distal part as the MEDIAL UMBILICAL LIGAMENTS.
What early tissues form the heart primordium? From which layer?
Cardiogenic LATERAL PLATE mesoderm –SPLANCHNOPLEURIC LAYER at the cranial end of the embryonic disc.
- ) The heart primordium comes from cardiogenic _______ at the ______ end of the embryonic disc.
- ) Most is ______ mesoderm from the ________.
- ) Mesoderm outflow portions of the heart is cranial mesoderm from the _______ and _______.
- ) Cardiogenic mesoderm at the cranial end of the embryonic disc.
- ) Most is splanchnic mesoderm from the primitive streak.
- ) Mesoderm outflow portions of the heart is cranial mesoderm from the NEURAL CREST and PARAXIAL COLUMNS.
p. 83 Netter
Blood vessels first appear in what three places?
- ) next to the intraembryonic coelom in the lateral plate
- ) cardiogenic mesoderm (cranial end of embryonic disc)
- ) extraembryonic mesoderm of the yolk sac and connecting stalk.
During the ______ week (approximately ______ days), the primordial atrium and the sinus venosus, as well as the veins draining into them, are evident.
During the fourth week (approximately 24 days)
p.194
What embryonic tissue layer(s) forms the epicardium (visceral pericardium)?
Epithelial cells from the cardiac mesoderm on the sinus venosus migrate over the myocardium to form the epicardium (visceral pericardium).
p.95 Netter
The primordial heart initially appears ______ to the oropharyngeal membrane, but later becomes ______ to the oropharyngeal membrane and ______ to the foregut.
The primordial heart initially appears cranial to the oropharyngeal membrane, but later becomes caudal to the oropharyngeal membrane and ventral to the foregut
What promotes fusing of the heart tubes into a single tube?
In what direction does the fusing take place?
- Lateral folding
- Cranial to caudal
p. 195
The primordial myocardium is formed from the __________ surrounding the __________.
splanchnic mesoderm surrounding the pericardial coelom
p.195
The heart and the pericardial cavity appear ventral to the _______ and caudal to the __________.
ventral to the foregut and caudal to the oropharyngeal membrane.
p.196
What is the bulbus cordis composed of?
bulbus cordis (composed of the truncus arteriosus, the conus arteriosus, and the conus cordis) p.195
Why does the heart bend on itself and form a U-shaped bulboventricular loop?
Because the bulbus cordis and the ventricle grow faster than the other regions
p.197
What primordial structure(s) forms the transverse pericardial sinus?
The degeneration of the central portion of the dorsal mesocardium (a mesentery that suspends the heart from the dorsal wall).
Blood enters the sinus venosum from which three sites and through which vessels?
- ) The embryo through the common cardinal veins
- ) The placenta through the umbilical veins
- ) The umbilical vesicle through the vitelline veins
p. 198
The sinus venosus enters the _____ aspect of the primordial ______.
Dorsal aspect of the primordial atria.
Why do the sinus horns enlarge? (2)
Due to…
- ) Changes in the umbilical and vitelline veins
- ) Anastomoses of the left and right anterior cardinal veins (brachiocephalic veins and SVC).
What are the two main embryonic tissue sources for the heart?
Paraxial mesoderm and neural crest cells
Partitioning of the atrioventricular (AV) canal, the primordial atrium, and the ventricle begins at approximately the middle of the _____ week and is essentially completed by the end of the ______ week.
begins at approximately the middle of the fourth week and is essentially completed by the end of the eighth week.
p.199
- ) What is the purpose of the foramen primum? Where does it occur?
- ) What does it become?
- ) Allows shunting of oxygenated blood from the right to the left atrium – Occurs between the developing right and left atrium.
- ) It closes and becomes the primordial AV septum.
p. 199
After birth, the oval foramen functionally closes due to ___________, and the valve of the oval foramen fuses with the _________, forming the oval fossa.
- higher pressure in the left atrium
- septum secundum
p. 202
By the end of the fourth week of development, the _____ sinual hom becomes larger than the ____ sinual horn.
right sinual hom becomes larger than the left sinual horn
p.202
What becomes of the right and lift sinual horns?
Right: Becomes incorporated into the wall of the right atrium.
Left: Becomes the coronary sinus.
p.202
Which parts of the atrium are derived from the primordial atrium?
The trabeculated portions (auricle and anterior internal surface that is not the sinus venarum).
p.202
Most of the wall of the left atrium is smooth because why?
What about the left auricle?
It is formed by the incorporation of the primordial pulmonary vein.
- The small left auricle is derived from primordial atrium and, thus, has a trabeculated appearance.
p. 202
The IV foramen usually closes by the end of the ______ week as the _____ fuse with the ______.
- by the end of the seventh week
- bulbar ridges fuse with the endocardial cushion.
Closure of the IV foramen results from fusion of tissue from which three sources?
- ) Right bulbar ridge
- ) Left bulbar ridge
- ) Endocardial cushion
p. 202
Where is the smooth part of the right atrial wall (_____) derived from?
(Sinus venarium) –Derived from the RIGHT SINUAL HORN.
p.203
Where are the crista terminales, valves of IVC and coronary sinus derived from?
RIGHT SINUATRIAL VALVE.
p.203
The primordial right atrium becomes the ______.
Right auricle.
p.203
Active proliferation of which type of cells form the bulbar ridges? When?
Mesenchymal cells in the walls of the bulbus cordis.
- During the 5th week.
p. 203
The bulbar and truncal ridges are derived mainly from the _________________.
neural crest mesenchyme
p.203
The spiral orientation of the bulbar and truncal ridges, possibly caused in part by__________________, results in the formation of a spiral ____________ when the ridges fuse.
- the streaming of blood from the ventricles
- aorticopulmonary septum.
p. 203
What is the function of the aorticopulmonary septum?
It divides the bulbus cordis and the truncus arteriosus into two arterial channels: the aorta and the pulmonary trunk.
p.204
Because of the ______________, the pulmonary trunk twists around the ascending aorta.
spiraling of the aorticopulmonary septum
p.204
In the right ventricle, the bulbus cordis is represented
by the _______, which gives origin to the ________.
- conus arteriosus (infundibulum)
- pulmonary trunk
p. 204
In the left ventricle, the bulbus cordis forms _________________. Describe what this structure is.
- the walls of the aortic vestibule.
- It is the part of the ventricular cavity just inferior to the aortic valve.
p. 204
The initial contractions of the heart originate in _______ during week ______.
muscle –During WEEK 4
p.198