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What is process of development?
Begins with zygote and divides to form embryo.
What are the three phases of early embryonic development?
cleavage, gastrulation, organogenesis
What is cleavage?
The first phase is cleavage,which produces a ball of cells, called a blastula, with an interior,liquid-filled cavity
The second phase is gastrulation, in which the blastula’s cells rearrange themselves into three layers that give rise to specific organs and tissues.
Gastrulation produces an embryo composedof three layers of cells: endoderm, mesoderm, ectoderm. What are their functions?
- The endoderm gives rise to interior tissues(the liver and bladder, for example).
- The mesoderm gives rise to tissues exterior to these (muscle and skeletal systems).
- The ectoderm gives rise to tissues that are more exterior yet (the skin, many sensory organs, and nervous system).
Organogenesis is when organs begin to form.The evelopment of the neural tube is such case. What's the process?
- In early organogenesis in vertebrates, a rod-shaped support organ, called a notochord, develops near the dorsal surface.
- It induces the development of ectodermal tissue that lies above it.
- A neural plate develops from this tissue, folding over on itself to form a hollow neural tube that gives rise to both the brain and the spinal cord.
What is cell proliferation?
- For an embryo to grow and develop, its cells need to divide and make more cells
- The location, timing, and extent of cell division have to be tightly controlled
- In plants and animals, most cells stopgrowing when they mature, but there are exceptions