Chapter 42 Animal Development Flashcards
What does housing refer to?
Place where embryo develops.
What does aiding and abetting the young called?
Feeding.
Can skin secretions be used for feeding?
Yes.
What are the 3 mechanisms of embryonic development?
Cleavage, gastrulation, and organogenesis.
Where do the instructions for the development from embryo to organism come from?
Zygotes’ nucleus and the maternal cytoplasm.
What directs the first stages of development in the embryo?
Maternal cytoplasm in zygote.
What are the mRNA and proteins stored in cytoplasm that direct the first stages of development called?
Cystoplasmic determinants
When can polarity arise?
Unequal distribution of yolk.
What produces bilateral symmetry?
Unequal distribution of egg.
What are the 3 axis created by polarity?
Dorsal-ventral, anterior-posterior, and right-left.
What are 3 characteristics of animal pole?
Less yolk, faster cell division, and gives rise to surface structures and anterior part of body. (Easy to develop skin)
What are 3 characteristics of vegetal pole?
Slow division, gives rise to internal structure and posterior end of body, and more yolk.
What are the blastula cells called?
Blastomeres
What is the solid ball of cells during the cleavage called?
Morula.
Why doesn’t embryo size increase during cleavage?
Because the maternal cytoplasm content remains the same.
What is the human blastula called?
Blastocyst.
What is gastrulation?
Rearrangement of cells in blastula to form the 3 germ layers.
At what stage of development is the body pattern established?
Gastrulation.
At what stage of development does the archenteron formed?
Gastrulation.
What is the archenteron lined with?
Endoderm.
What are the 6 mechanisms controlling development?
Mitotic divisions, cell movement, selective cell adhesion, induction, determination, and differentiation.
What is selective cell adhesion?
The phase where cells choose to break or make connections to other cells or ECM.
What are the 4 extraembryonic membranes?
Amnion, chorion, yolk sac, and allantois.
How is the yolk distributed in sea Urchin?
Evenly.
Does cleavage take place at the same rate in sea urchin?
Yes.
Where does invagination and gastrulation begin in sea urchin?
Flattened vegetal pole cells.
Determination is a product of what?
Induction
What triggers the primary mesenchyme to migrate into blastocoel in a sea urchin?
Inducation
Where does the mouth form during gastrulation in sea urchin?
Where archenteron touches the ectoderm.
Where do the secondary mesenchyme cells come from in sea urchin?
From the connection between archenteron to the ectoderm.
How is the yolk distribution in an amphibian development?
Uneven.
Where is the site for fertilization on a frog egg?
The grey side/ animal pole.
What color is the animal pole in an amphibian egg?
Grey (The dark side of humans)
How and where is the dorsal-ventral side established on a frog egg?
Rotation of pigment layer after fertilization. The dorsal side is the grey crescent.
Where does the 1st cleavage occur in from embryo?
Across the grey crescent.
How does a dorsal lip form?
When animal pole cells migrate to the grey crescent and create a depression.
Is gastrulation in frog symmetrical?
No
What is a major induction center in frog embryo?
Dorsal Lip.
What is a yolk plug?
Cells of vegetal half.
What is the first thin layer of cells that forms in bird embryo?
Blastodisk (disk=thin).
What 2 layers does the blastodisk get transformed into?
Epiblast and hypoblast.
What layer produces the 3 germ line cells in bird embryo?
Epiblast.
What kind of cell line does a hypoblast produce in bird embryo?
Germ line that lead to development of egg and sperm in embryo.
What is the difference between primitive groove and primitive streak?
Primitive streak is just a line when epiblast cells move towards middle of blastodisk. Primitive groove forms when the midline sinks.
What do the cells that move laterally from epiblast cells into blastocoel form in chick embryo?
Mesoderm.
What do the cells that move straight down from epiblast cells into blastocoel form in chick embryo?
Endoderm.