Changes

For most domestic mammalian embryos, the pre-attachment period within the uterus is long (several weeks). During this time, extraembryonic membranes form by a folding process that generates:  

For most domestic mammalian embryos, the pre-attachment period within the uterus is long (several weeks). During this time, extraembryonic membranes form by a folding process that generates:  

1. Amnion

1. '''Amnion'''

2. Chorion

 

3. Allantochorion

2. '''Chorion'''

 

3. '''Allantochorion'''

In primates, the blastocyst implants very soon after it enters the uterus and extraembryonic membranes form after implantation.

In primates, the blastocyst implants very soon after it enters the uterus and extraembryonic membranes form after implantation.

1.'''Epiblast''' - facing towards the uterine lumen, adjacent to syncytiotrophoblasts.

1.'''Epiblast''' - facing towards the uterine lumen, adjacent to syncytiotrophoblasts.

2.'''Hypoblast''' - facing towards the endometrium, adjacent to the blastocyst cavity.

2.'''Hypoblast''' - facing towards the endometrium, adjacent to the blastocyst cavity. The hypoblast gives rise to no persisting structure in the adult.

3.'''Amnioblasts''' - cells of the epiblast that migrate up and around to allow the amniotic cavity to form.  

3.'''Amnioblasts''' - cells of the epiblast that migrate up and around to allow the amniotic cavity to form.  

After [[Gastrulation - Anatomy & Physiology|gastrulation]], the '''epiblast''' gives rise to the three germ layers:

After [[Gastrulation - Anatomy & Physiology|gastrulation]], the '''epiblast''' gives rise to the three germ layers:

1. Ectoderm

1. '''Ectoderm'''

 

3. Endoderm

2. '''Mesoderm'''

The hypoblast gives rise to no persisting structure in the adult.

3. '''Endoderm'''

[[Category:Developmental Biology]]

[[Category:Developmental Biology]]

[[Category:Pregnancy and Parturition]]

[[Category:Pregnancy and Parturition]]

[[Category:To Do - AimeeHicks]]

[[Category:To Do - AimeeHicks]]