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36 Cards in this Set
- Front
- Back
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What are pronuclei?
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Female and male nucleus found in ova
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What is a zygote?
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Inital cell formed by fusion of sperm with egg
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What is an embryo?
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Zygote that has undergone cleavage stage (cell division)
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What is a blastomere?
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Individual cells produced by cleavage of zygote
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What is a morula?
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Ball of cells (blastomeres) surrounded by zona pellucida
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What is a blastocyst?
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Inner cell mass surrounded by cavity (blastocoel), trophoblast (placenta) and zona pellucida
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What is blastocyst hatching?
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Zona pellucida ruptures, allows blastocyst to squeeze out and implant on uterine wall
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What is blastocyst migration and elongation?
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Migration - even spacing of embryo
Elongation - allows trophoblast to form uterine horn contralaterally |
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What is a gastrula?
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Stage after blastula, in which one-layered blastula becomes 3 layered gastrula
(3 layers = derms) |
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What is the primitive node?
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Organiser for gastrulation
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What is anterior and posterior?
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Anterior - cranial
Posterior - caudal |
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How is the mesoderm formed?
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Invagination of epiblast cells at caudal end of primitive streak
EMT (epithelial to mesenchmye transition) |
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What is the notochord?
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Primitive backbone
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What does mesoderm form?
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Heart connective tissue bone muscle kidney blood vessels
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What is the amniotic cavity?
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Surrounds developing body, protects foetus
Somatopleure |
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What is the yolk sac?
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Developing circulatory system (erythropoesis)
Splanchnopleure Provides nutrition in non-mammals |
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What is the allantois?
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Allows gas exchange, stores urine
Splanchnopleure |
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What is the chorion?
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Membrane that exists between foetus and mother
Somatopleure Keeps membrane wet and protects it |
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What happens in primary neurulation?
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Neural plate folds in to form neural groove
Two edges of neural fold meet and fuse to form the neural tube. Continues cranially and caudally |
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What does the neural plate form?
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CNS
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Where are neural crest cells located and where do they migrate to?
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Dorsal aspect of neural fold
Migrate to lateral sides of groove, become mesenchymal |
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What is the branchial/pharyngeal arch?
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Series of mesodermal outpouchings from the developing pharynx
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What are branchial pouches and branchial clefts?
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Pouches -endodermal side between arches
Branchial - ectodermal side |
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Upper limb forms before lower limb
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u
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What is the apical ectodermal ridge?
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Thickening of ectoderm and distal end of limb bud
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What does the notochord form?
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Nucleus pulposus of intervertebral discs
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What is: a)somatopleure and b)splanchopleure
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a)outer part of mesenchyme fused to ectoderm
b)inner part fused to endoderm |
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Parts of gut and which way they extend?
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Foregut (cranially)
Midgut Hindgut (caudally) |
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What is the dorsal mesentery?
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Suspends the gut
Splanchnopleure mesoderm |
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What divides the body cavity?
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Septum transversum
pleuro-pericardial and peritoneal |
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What are the 4 stages of foetal development?
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Blastulation
Gastrulation Organogenesis Foetal development |
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How does the primitive node organise gastrulation?
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Signalling molecules
Nodal, noggin, FGF |
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What is a homologous gene?
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A gene derived from shared ancestor
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How does Nodal lead to left-right asymmetry?
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Only found on left side of body
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What is a homeotic mutation?
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Transformation of one segment into another one
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How are homeotic genes in fruit flies important?
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Colinearity - sequence of the homeotic genes lines up to the part of the body they affect
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