Embryo past paper 4

Cleavage can be described as:

• Completion of second meiotic division

• Mitotic divisions producing blastomeres

• Formation of blastocoel

• Initiation of fertilization

Blastocyst:

• Is formed at the 2-cell stage

• Is implanted early in the first week

• Is formed from morula with a cavity

• Contains liquor folliculi

Amnioblasts derive from:

• Hypoblast

• Trophoblast

• Amniotic cavity

• Epiblast

Endodermal cells give rise to:

• Epidermis of the ventral body wall

• Dermis of the limbs

• Epithelial lining of respiratory tract

• Lining of amniotic cavity

Somitomeres derive from:

• Endoderm

• Paraxial mesoderm

• Intermediate mesoderm

• Lateral mesoderm

Optic placodes derive from:

• Ectoderm

• Paraxial mesoderm

• Endoderm

• Neural crest

Septum transversum:

• Forms epicardium

• Formed by splanchnic mesoderm around the heart

• Forms ligament in the liver

• Formed by somatic mesoderm

Heuser’s membrane lines the:

• Amniotic cavity

• Primitive yolk sac

• Chorionic cavity

• Extraembryonic cavity

Chorionic villi at the end of 3rd week contains:

• Cytotrophoblast, Syncytiotrophoblast, Mesoderm, Capillaries

• Endoderm, Cytotrophoblast, Syncytiotrophoblast, Mesoderm core

• Capillaries, Syncytiotrophoblast

• Cytotrophoblast, Endoderm

The fetal part of the placenta is derived from:

• Decidua basalis

• Decidua capsularis

• Chorion frondosum

• Amnion