What kind of tissues arise from each of the three embryonic germ layers?
Ectoderm: Epidermis of skin and epidermal derivatives: hair,
nails, glands of skin; linings of oral, nasal, anal, and vaginal
cavities. Nervous tissue; sense organs. Lens of eye, enamel of
teeth, pituitary gland, adrenal medulla.
Mesoderm: muscle; smooth, cardiac, and skeletal. Connective tissue; cartilage, bones, blood. Dermis of skin, dentin of teeth, epithelium of blood vessels, lymphatic vessels, body cavities, joint cavities. Internal reproductive organs. Kidneys and ureters. Adrenal cortex.
Endoderm: Epithelium of pharynx, external acoustic canal, tonsils, thyroid, parathyroid, thymus, larynx, trachea, lungs, GI tract, urinary bladder and urethra, and vagina. Liver and pancreas.
Animals that have three layers of embryonic tissue with organs in a cavity that is completely lined with mesoderm are what?
All human tissues stem from three primitive embryonic germ layers, the endoderm, mesoderm and ectoderm. The endoderm produces most of the lining and structure of the gastrointestinal tract along as well as the respiratory tract and epitelia of other organs. The mesoderm gives rise to structures including bone, cartilage, muscle, connective tissue (including that of the dermis), blood vascular, reproductive, excretory and urinogenital systems and contributes to some glands. The ectoderm most notoriously forms the…
There are adult stem cells and there are embryonic stem cells. Adult stem cells are found in many body tissues such as in the brain, neural stem cells, and in bone marrow. Also the embryonic stem cells, as you can tell by the name, are from the embryo which starts to develop into more recognizable specialized stem cells within three to four weeks after fertilization.
At the beginning of week three after fertilization the embryo is in the the form of a bilaminar disc with the epiblast layer on top, continuous with the amniotic cavity and the hypoblast layer below, continuous with the yolk sac. Gastrulation is process by which this bilaminar (2 layer) disc becomes three germ layers: the endoderm, the mesoderm and the ectoderm. The primitive streak forms from a thickened band of epiblast cells. These cells proliferate…
Bones do not come from a type of tissue, however in the most basic sense bones are formed from the mesoderm, one of the three layers to a blastopore during early amniotic development. The mesoderm is also responsible for the creation of muscle tissues. Bone initially begins as cartilage, such as what is in your ear, then hardens after birth to become bone.
Gastrulation is defined as a phase early in the embryonic development of most animals, during which the single-layered blastula is reorganized into a trilaminar structure known as the gastrula. These three germ layers are known as the ectoderm, mesoderm, and endoderm. These develop into the respiratory and digestive organs.