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What is process of development?
Begins with zygote and divides to form embryo.
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What are the three phases of early embryonic development?
cleavage, gastrulation, organogenesis
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What is cleavage?
The first phase is cleavage,which produces a ball of cells, called a blastula, with an interior,liquid-filled cavity
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Gastrulation is...
The second phase is gastrulation, in which the blastula’s cells rearrange themselves into three layers that give rise to specific organs and tissues.
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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).
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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.
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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
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