Animal%20Development

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• Chapter 47
• Animal Development

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Embryonic development/fertilization

• Preformation until 18th century miniature
  infant in sperm or egg
• At fertilization/conception
• Acrosomal reaction hydrolytic enzyme action on
  egg jelly coat.
• Fast block to polyspermy membrane depolarization
  prevents multiple fertilizations.
• Cortical reaction release of calcium causes
  hardening of egg outer layer and creates a...
• Slow block to polyspermy and...
• Egg activation increases metabolic activity
  protein synthesis

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The Fertilized Egg Cleavage

• Blastomeres resultant cells of cleavage/mitosis
• Yolk nutrients stored in the egg
• Vegetal pole side of egg with high yolk
  concentration
• Animal pole side of egg with low yolk
  concentration
• Morulasolid ball of cells
• Blastocoelfluid-filled cavity in morula
• Blastulahollow ball stage of development

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Gastrulation

• Gastrula 2 layered, cup-shaped embryonic stage
• 3 Embryonic germ layers
• Ectoderm outer layer epidermis nervous system,
  etc.
• Endoderm inner layer digestive tract and
  associated organs respiratory, etc.
• Mesodermskeletal muscular excretory, etc.
• Invagination gastrula buckling process to create
  the...
• Archenteron primitive gut
• Blastopore open end of archenteron

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Organogenesis organ formation

• Blastodisc cap of cells on top of yolk
• Primitive streak invagination of blastodisc
• Neural tube beginning of spinal cord
• Somites vertebrae and skeletal muscles
• Neural crest bones and muscles of skull

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Amniote embryos

• Extraembryonic membranes yolk sac (support
  circulatory function) amnion (fluid-filled sac
  protection) chorion (placenta
  formation)
• allantois (nitrogenous waste)