Embryonic Development

It is the attachment of blastocyst to the uterine wall.

It is the covering of heart called the pericardium, and the membrane that surrounds the lungs is called the pleura. It is produced by mesoderm.

It is a small sac that pushes out from the gut of embryo near the yolk sac.

In human beings, during the fourth week after fertilisation, the embryo develops a simple heart.

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Metamorphosis is a profound change in form from one stage to the next in the life history of an organism, as from the caterpillar to the pupa and from the pupa to the adult butterfly.

Metanephric kidney is the functional kidney of adult reptiles, birds and mammals.

Excretory products of mammalian embryo are eliminated by placenta.

The solid ball of cells ,resembling mulberry fruit ,resulting from the cleavage of zygote  is called morula .

 Amniotic sac is protected to the inner side by a membrane called amnion and towards the outer side is protected by a membrane called chorion.

 Gastrula stage follows after blastula and during this stage the cells of blastula develop into a tri-laminar structure and the three germ layers namely ectoderm,mesoderm and endoderm develop.

 Many types of cell movements occur during gastrula stage of human embryo and ingression is one such stage when cells leave an epithelial sheet to become freely migrating mesenchyme cells.

Mammalian zygote undergoes total cleavage as yolk is less in amount and thus holoblastic .

 Cartilage is formed from condensed mesenchyme tissue during organogenesis and this is called chondrogenesis.