Germ Layers by 4ZtQyQU

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									                                           Germ Layers

ECTODERM
Top cell layer of the embryonic disc. Will later form skin, hair, lenses of the eyes, lining of the
internal and external ear, nose, sinues, mouth, anus, tooth enamel, pituitary and mammary glands,
and all parts of the nervous system.

MEDODERM
Middle cell layer of the embryonic disc. The precursor to the muscles, bones, lymphatic tissue,
spleen, blood cells, heart, lungs, reproductive and excretory systems.

ENDODERM
Inner cell layer of the embryonic disc. Will later form the lining of the lungs, the tongue, tonsils,
urethra and associated glands, bladder and digestive tract.


                                               Zygote

                                               Blastula

                                              Gastrula

Ectoderm                                                                Endoderm

Epidermis and              Brain                                        Embryonic gut
associated                 nervous
structures                 system                       Lining of            Glands          Lining of
(skin, nails, etc.)                                     digestive                            respiratory
                                                        tract                                tract




                                             Mesoderm

                           Notochord                                    Somites

                                                        Muscle                        Outter covering
                                                                                      of internal organs

                                                                 Excretory       Gonads

                                             Mesenchyme

                  Dermis                Circulatory system              Bones and cartilage

Taken from: http://www.luc.edu/faculty/wwasser/dev/layer.htm

								
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