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42 Cards in this Set
- Front
- Back
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what is the morula? |
solid ball of embryonic cells that develops after the first 3 cleavages of the zygote following fertilization
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what are the 3 stages of embryonic development?
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1. cleavage
2. gastrulation 3. organogenesis |
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what is cleavage?
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the rapid mitotic cell division of the zygote that occurs immediately after fertilization.
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what is determinant cleavage?
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where the future differentiation pathways are determined for a cell.
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what is indeterminate cleavage?
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a cleavage in which cells retain the ability to develop into a complete and normal embryo.
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when does blastulation begin?
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when the morula develops the blastocoel (fluid filled cavity) which then becomes a blastula.
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what is a blastula?
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hollow sphere of cells that develops from the morula after blastulation begins
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what are the cells of the blastula called?
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blastomeres
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what does gastrulation do?
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produces 3 germ layers: ectoderm, endoderm, and mesoderm.
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what is gastrulation?
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rearrangement of the blastula to form 3 germ layers
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what is the archenteron?
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a cavity formed when cells on the surface migrate into the blastopore
(primitive gut) |
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what is the result of the formation of the archenteron?
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the 3-layered gastrula is formed
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what does the gastrula consist of?
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3 embryonic germ layers: ectoderm, endoderm, and mesoderm.
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what germ layer is responsible for the skin and nervous system?
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ectoderm
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what germ layer is responsible for the epithelial linings of the digestive and respiratory tracts and parts of the liver, pancreas thyroid and bladder lining?
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endoderm
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what germ layer is responsible for the development of the musculoskeletal system, circulatory system, excretory system, gonads, muscle ?
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mesoderm
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what development is the ectoderm responsible for?
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nervous system, & skin.
integument(hair, nails, mouth, anal canal, lens of eye, retina) |
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what development is the mesoderm responsible for?
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muscle and bone and blood, as well as excretory system & gonads.
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what development is the ectoderm responsible for?
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skin & nervous system
(& hair, nails, epithelium of nose, mouth and anal canal, the lens of eye, & retina) |
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what development is the endoderm responsible for?
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the viscera (lungs, liver, digestive organs)
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what is organogenesis?
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organ building - cells continue to differentiate.
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what is an example of embryonic induction?
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amphibian dorsal lip - ability of one group of embryonic cells to influence the development of another.
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what is cytoplasmic determinants?
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the importance of cytoplasm in the development of the embryo
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what germ layer gives rise to the digestive tract?
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endoderm
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what germ layer gives rise to the brain and eye?
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ectoderm
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what germ layer gives rise to the blood and bone?
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mesoderm
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what are hox genes?
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"homeotic genes" master genes that control the expression of other genes that regulate the placement of specific anatomical parts.
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where do sperm gain motility?
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epididymis
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one primary sex cell in females (oogonium) develops into how many active egg cells?
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one active cell and 2 polar bodies
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how does gas exchange occur in the fetus?
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across the placenta
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what part of an egg provides fetus with nutrients?
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yolk
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what is the chorion?
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membrane that lines the inside of the shell and permits gas exchange
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what is the allantois?
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analogous to the placenta in mammals; respiratory gases from environment to embryo and serves a waste-removal function.
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what is the amnion?
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protects the embryo from shock, contains amniotic fluid
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do marsupials have a placenta?
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no
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what function do the placenta and umbilical cord serve?
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supply oxygen and nutrients to fetus and removes carbon dioxide and metabolic wastes as well.
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what are the four extra-embryonic membranes formed during human development that are also found in eggs?
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1. chorion
2. amnion 3. yolk sac 4. allantois |
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what are the four extra-embryonic membranes formed during human development involved in?
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the placenta and umbilical cord
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what does oxytocin do?
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induce labor
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what hormone is released by the hypothalamus and stimulates the anterior pituitary?
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GnRH
(gonadotropic-releasing hormone) |
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what hormone stimulates the ovary to make a secondary oocyte?
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FSH
(follicle stimulating hormone) |
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what hormone stimulates sperm production?
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FSH
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