HT, GV, AS/GV, FC, ChaB Flashcards
In which layer are blood islands developed in?
Mesoderm
What 3 locations do blood islands develop in?
- Region of future heart
- Both sides of notochord
- Wall of yolk sac and connecting stalk
What 3 things do blood islands form?
- Heart
- Blood vessels
- Blood cells
What is the embryonic coelom?
Angle between amniotic cavity and yolk sac
What 3 parts does the embryonic coelom differentiate into, and what do these parts become?
- Rostral/cranial part becomes pericardial coelom, which will later become the thorax.
- Caudal/tail end becomes peritoneal coelom, which is the abdominal region.
- Connecting the 2 coelom is the Pericardioperitoneal Canal, in the thoracic region.
What will the oropharyngeal membrane eventually close then rupture to become?
It will close the foregut to become the mouth
What will the cloacal membrane eventually close then rupture to become?
It will close the hindgut to become urogenital and anal openings
What are the folds of the embryo?
4 folds (2 lateral, 1 cranial, and 1 caudal)
What does the lateral folding cause?
The heart tube bends in the middle
What does the cranial folding cause?
Brings the heart into the developing thoracic region
While the heart is still developing, how does blood enter and leave?
Blood enters caudally from sinus venosus and is pumped out by truncus arteriosus
What are the 3 types of circulation in the embryo?
- Umbilical
- Vitelline
- Embryonic
Purpose of umbilical circulation?
Acquire oxygen and nutrients through placenta and disposes of waste
Purpose of vitelline circulation?
Picks up fresh blood cells from site of production (wall of yolk sac)
Purpose of embryonic circulation?
Nourishment of embryo as delivered to tissues of embryo
What structures seen in the adult heart prove the twisting of the primitive heart?
Ascending aorta and pulmonary trunk spiral slightly as they ascend
What is the endocardial cushion?
Cells growing between the atria and ventricle that will give rise to the septum and heart valves.
What is the septum primum?
Starts to divide atria medially
What is the foramen primum?
Diminshing space between endocardial cushion and septum primum
What is the septum intermedium?
Divides atrium and ventricle and fuses with the septum primum
What is the foramen secundum?
Space that arises from the middle of the septum primum breaking down after fusing with septum intermedium
What is the septum secundum?
Grows next to septum primum within right atrium region
What is the foramen ovale?
Space between septum primum and septum secundum
Describe how the definitive interventricular septum arises?
First, ventricular septum arises from bottom, which is muscular.
Then, septum intermedium grows downwards to form fibrous sheet that will fuse with muscular part.
Together = interventricular septum
