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23 Cards in this Set
- Front
- Back
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4 stages of development
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-Cleavage
-Gastrulation -The formation of adult structures -Sexual maturation |
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Cleavage
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-Zygote divides mitotically without an increase in size
-A solid round ball of cells is formed (morula) -The morula develops an internal cavity (blastocoel) --Becomes a blastula |
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Gastrulation
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-forms Endoterm (inner), Misoderm (middle), and Ectoderm (outer)
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Organs form from each embryonic cell layer
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-organogenesis
-survival signal, death signal |
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development
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the process by which an organism proceeds from fertilized egg through adulthood
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differentiation
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the specialization of embryonic cells into different cell types
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_______ contains all the genes needed to direct the construction of the entire organism
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The zygote
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development is regulated by
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gene transcription
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Homeobox sequences
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-short DNA sequences within genes that encode for DNA-binding proteins
--proteins bind to DNA and control which genes are expressed during development |
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Morula
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formation of a solid ball of cells created by cell division
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after 1 week, a Morula becomes a
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blastocyst, a hollow ball of cells with an inner cell mass on one side
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implantation
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during weeks 1–2, outer blastocyst wall adheres to uterus and burrows into endometrium
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chorion
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what outer cell layer become during weeks 1-2,
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embryonic disc
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future embryo
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2 fluid filled sacs inner cell mass splits into
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amniotic cavity and yolk sac
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chorionic villi
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-what chorion extends into endometrium, starting placenta formation
-contain fetal capillaries that bathe in maternal blood |
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Body stalk
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connects embryo to chorion
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Yolk stalk
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connects yolk sac and embryonic gut
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Umbilical cord made of
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merge of yolk stalk and body stalk
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Notochord
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prominent tail and gill grooves present
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the Placenta
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-Secretes estrogen and progesterone
--Stimulate uterine and mammary growth -Regulates exchange of material between the mother and fetus |
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Elevated estrogen and progesterone stimulate :
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mammary gland growth
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Colostrum fluid:
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-is released for several days after birth
-High in proteins and antibodies to help the newborn fight infection -Gradually replaced by mature milk --Contains high lactose and fat content, lower protein content |
