Day

The blastocyst is more deeply embedded in the endometrium, and the penetration defect in the surface epithelium is closed by a fibrin coagulum (Fig. 3.3). The trophoblast shows considerable progress in development, particularly at the embryonic pole, where vacuoles appear in the syncytium. When these vacuoles fuse, they form large lacunae, and this phase of trophoblast development is thus known as the lacunar stage (Fig. 3.3).

At the abembryonic pole, meanwhile, flattened cells probably originating from the hypoblast form a thin membrane, the exocoelomic (Heuser's) membrane, that lines the inner surface of the cytotrophoblast (Fig. 3.3). This membrane, together with the hypoblast, forms the lining of the exocoelomic cavity, or primitive yolk sac.

Emergency Panic Remedies

Emergency Panic Remedies

Eliminate Your Panic And Anxiety Attacks Instantly With These Proven Techniques! There’s
 very
 little
 in
 this 
world
 that 
is
 as 
frightening
 and
 uncomfortable
 as 
a panic
 attack. 

Once
 they
 start,
 panic
 attacks
 can
 send
 you
 spiraling
 out
 of control.

Get My Free Ebook


Post a comment