Angiogenesis and Folding of the Embryo

Flashcards about Angiogenesis and the Folding of the Embryo

What is Angiogenesis?

The formation of new vessels by budding and branching from preexisting vessels.

What is Vasculogenesis?

The formation of new vascular channels by assembly of individual cell precursors called angioblasts.

What is somatopleure?

Parietal layer together with extraembryonic mesoderm covering amnion and ectoderm.

What is splanchnopleure?

Visceral layer together with extraembryonic mesoderm covering yolk sac and endoderm.

What are the three body cavities that the intraembryonic coelom divides into during the 2nd month?

Pericardial, pleural, and peritoneal cavities.

Where does vasculogenesis and angiogenesis begin at the beginning of the third week?

Extraembryonic mesoderm of the umbilical vesicle, connecting stalk, and chorion.

Which cells differentiate into endothelial cell precursors called angioblasts?

Mesenchymal cells.

Angioblasts flatten to form what kind of cells?

Endothelial cells.

How do vessels sprout into adjacent areas during angiogenesis?

Endothelial budding and fusion with other vessels.

From where are the heart and great vessels developed?

Cardiogenic area.

From what does the heart tube fuse by the end of the 3rd week?

Endothelial heart tubes.

When does the heart beat and blood circulation start?

Day 21 or 22 (5 weeks after LNMP).

When does blood formation (hematogenesis) begin in the embryo?

Fifth week.

Where do primitive blood cells and plasma develop from (Embryonic Phase)?

Ventral mesoderm of yolk sac and allantois at the end of the 3rd week.

In what sequence does hemopoiesis occur in the embryo during the definitive phase?

Liver, then spleen, lastly bone marrow and lymph nodes.

What is the main force responsible for embryonic folding?

Differential growth of various embryonic structures.

What are the areas of folding in the embryo referred to as?

Cranial, caudal, and lateral body folds.

What causes the heart to be pushed caudally into its adult position during cranial folding?

Brain growth.

What is the stomodeum?

Invagination of ectoderm.

During caudal folding, what happens to part of the yolk sac?

To be incorporated into the hindgut.

What is the allantoic diverticulum?

An invagination of hindgut endoderm into the yolk sac.

The lateral folding of the embryo is due to the great enlargement of what structures?

Somites.

After the lateral folding, what happens to the communication between intra and extraembryonic coeloms?

The communication between the intra- and extraembryonic coeloms becomes constricted and eventually obliterated.

What are the results of the folding process in the embryo? Name as many as you can.

Embryo changes into a cylindrical embryo, transposition between septum transversum and cardiogenic plate, yolk sac reduced in size, allantois & connecting stalk repositioned, formation of umbilical cord, oral membrane becomes cranially ventral, and cloacal membrane and allantois become caudal ventral.