Definitions #3 Flashcards
(20 cards)
Morula
~ formed by cell division of zygote on day 4
~ secrete fluid and outermost cells become tightly bound together (compaction) –> blastula
Radial symmetry
symmetry around a central axis
Ectoderm
~ outside layer
~ forms skin, hair, nails, lens of eye, pituitary + mammary glands + ALL CNS
Mesoderm
~ middle layer
~ forms muscle, bones, lymphatic tissue, heart + lungs
Endoderm
~ inside layer
~ forms lining of lungs, tongue, urethra, bladder + digestive tract
What complex degrades Beta-catenin?
axin/GSK-3/APC destruction complex
Fizzled
receptor that promotes the activity of the protein dishevelled
Dishevelled
inhibits formation of axin/GSK-3/APC destruction complex
Which transcription factors promote transcription of the siamois and twin genes?
Beta-catenin + TCF3
Siamois and twin genes
act as transcription factors that promote expression of organiser genes w/in spemman’s organiser
Primitive groove
a depression w/in the primitive streak
BMPs
a.k.a. bone morphogenetic proteins
~ belongs to the Transforming Growth Factor-β (TGF-β) superfamily
~ involved in embryogenesis and bone growth
FGF
a.k.a. fibroblast growth factors
brings about neurulation in ectodermal cells
Fruitless
~ 1st regulatory gene responsible for male-courtship behaviours in flies
~ it retains male-specific circuits that die in females
cVA
binds to Lush (protein) which opens ion channels = increased frustration expression
Axonal growth cone
found at leading end of growing neurite and responds to different combinations of chemotropic molecules
Chemotropic molecules
diffusible + act over long distances (chemoattractants/repellants)
Netrins
~ made by floor plate of dev. spinal cord
~ chemoattractant that guides dev of commissural neurones
Commissural neurons
~ repelled by BMPs in dorsal spinal cord
~ attracted by netrins in floor plate of spinal cord
Ephrins + EPH receptors
repel migrating axon and cause growth cone collapse
