PHASES OF EMBRYONIC DEVELOPMENT 1

Gametogenesis

Fertilization

Cleavage

Blastulation

Gastrulation

Neurulation

Organogenesis

7 STEPS:

GAMETOGENESIS

a process by which the diploid germ cells undergo a number of

chromosomal and morphological changes to form mature haploid

gametes.

spermatogenesis

in testes produce sperms.

oogenesis

in ovary produce ova.

Animal Pole

the pole (end) of the egg where yolk is least concentrated.

Animal hemisphere

the hemisphere of the egg where animal pole is located

Vegetal pole

the pole (end) of the egg where yolk is the most concentrated.

Vegetal hemisphere

the hemisphere of the egg where vegetal pole is located

FERTILIZATION

the process whereby two sex cells (gametes) fuse together to create a new individual with genetic potentials derived from both parents

CLEAVAGE

the process of repeated rapid mitotic cell divisions of the zygote (unicellular structure) to form the Blastula (multicellular structure)

Blastomeres

the produced cells of cleavage

Morula

cleavage continues divisions to form a ball of 32 cells called

Blastocoel

The cavity of the blastula is called

BLASTULATION

The result (end period) of cleavage

BLASTULATION

The production of a multicellular blastula

Blastomeres

Blastula cells are called what

GASTRULATION

rearranges the cells of a blastula into a three-layered (triploblastic) embryo that has a primitive gut.

Gastrula

The blastula develops a hole in one end and cells start to migrate into

the hole; this forms the

Gastrocoel

in gastrulation, blastocoel gradually disappear and a new cavity is formed which is called what

Gastrula

a three-layered embryo

Endoderm
Mesoderm
Ectoderm

the three primary embryonic germ layers

NEURULATION

formation of a dorsal, hollow neural tube

neural plate

ectodermal cells flatten into

neural groove

the center of the plate sinks forming

neural folds

edge of plate is elevated to form

neural tube

neural folds fuse and form

Neural crest

a critical structure that guides formation of several organ systems

Neural crest

forms on either side of the point of fusion

ORGANOGENESIS

the formation of the organs

Endoderm

The innermost layer

Endoderm

Goes on to form the gut, lining of digestive tract, liver, pancreas, lungs

Mesoderm

Goes on to form the muscles, circulatory system, blood, many different

organs,muscles, skeleton, gonads, excretory system, circulatory

system.

Ectoderm

The outermost

Ectoderm

Goes on to form the skin and nervous system

nervous system

the first organ system to develop.