Embryo T3 Flashcards
What mutant has specific behavioral defects related to the cerebellum?
Due to what abnormal cell?
Formation of what abnormal
Weaver
Radial glial cells in cerebellum
Formation of granular layer of the cerebellar cortex
What is characterized by abnormal behavior and absence of normal cortical layering?
What is defective?
What does this do?
Reeler
Reelin: extracellular protein defective
Reelin: may serve as a stop signal for radial neuronal migration or as an insertional signal for migrating neurons
A closure defect in spinal cord
Rachischisis
Spinal cord and meninges remain in place but bony covering is incomplete
Spine bifida occulata
Dura mater may be missing in the area of the defect and the arachnid layer bulge prominently beneath the skin. Spinal cord remains in place
Meningocele
Spinal cord bulges or is entirely displaced into the protruding subarachnoid space
Myelomeningocele
Major derivatives of diencephalon?
Epithalamus
Thalamus
Hypothalamus
Rostral patterning center?
FGF-8
What may serve as a stop signal for radial neuronal migration or as an insertional signal for migrating neurons
Reelin
Dorsal patterning center?
BMPs and Wnts
Ventral patterning center
Shh
What is the major topographical change in the myelencpehalon?
Pronounced expansion of the roof plate to form the thin roof overlying the fourth ventricle
Express of what genes is responsible for differentiation of nuclei in myelencephalon?
Hox genes
Neural crest cells are from what?
Neural plate
While in the neural tube neural crest cells are?
Epithelial
What factors are involved in breaking free of the neural tube?
Snail-1, Snail-2, and Foxd3
Neural crest cells form many components of the nervous system but do not form what?
Motor neurons
Neural crest cells from trunk transplanted into head form most neural crest derivates except
-What also differentiates
Cartilage or skeletal elements (even though normally do)
Some cells differentiate into cholinergic parasym instead of adrenal sympathetic normally produced
Pathway of cells in circumpharyngeal ridge
Migrate ventrally and then cranially to provide pathway for XII and related musculature
Most neural crest cells from somites 1-3
Pass into pharyngeal arches 4 and 6 or form cardiac crest
Neural crest cells from somites R4-R7
Make up vagal crest
Form parasympathetic innervation for digestive tract
Vagal neural crest
- Associated with
- Para or Sym
- Factor
Gut enteric system
Parasympathetic
Mash-1
What maintains the competence of neural cells to differentiate into autonomic neuron?
Mash-1
What is involved in various pigment defects (white strip), deafness, cleft palate, ocular hypertelorism
- What crest(s)
- Mutation
Waardenburgs syndrome
Trunk and cranial
Pax3 mutations
What is characterized by coloboma, heart disease, atresia of nasal chonanae, retardation of development, genital hypoplasia in males, and anomalies of ear
-What crest(s)
CHARGE
Trunk and cranial
What is characterized by hypoplasia and reduced function of thymus, thyroid, and parathyroid glands and cardiovascular defects
- What crest(s)
- Mutation
DiGeorge Syndrome
Cranial
Deletion of Chr 22
What is a genetic disease manifested by multiple tumors of neural crest origin?
Neurofibromatosis
What is characterized by cafe au lait spots, peripheral nerve tumors, gigantism
Neurofibromatosis
Preplacodal region is induced by
Involves activation of
Involves inhibition of
Cranial mesoderm
Activation FGF
Inhibition of Wnt and BMP
In preplacodal region low concentration of BMP form
Placodes
In preplacodal region intermediate concentration of BMP form
Neural crest
In preplacodal region high concentration of BMP form
Neural plate
What induces formation of lens placed from lens ectoderm?
Optic vesicle
Absence of Pax6 in eye development
Optic vesicle can’t induce formation of lens placode
What induces ectoderm to form neural plate
Chordamesoderm
What induces neural crest to form choroid, sclera?
Optic cup
What induces the formation of lens from lens vesicle?
Primitive retina and neural retina
Corneal epithelium is induced to from cornea by what?
Lens vesicle
Optic stalk is a lateral evagination of what?
diencephalon
groove in optic vesicle is what?
Choroid fissure
What runs in the choroid fissure?
Hyaloid artery to posterior chamber
What occurs in absence of Pax6
Early formation of optic vesicle but rest of eye doesn’t form
Optic vesicle can’t induce lens ectoderm
What inhibits expression of Pax 6
High concentrations of Shh
Low concentrations of Shh in distal optic stalk permits expression of Pax6 and development of what
Leads to formation of what
Optic vesicle
Retina
High concentrations of Shh in proximal optic stalk induces what
-Fxn
Expression of Pax2
-Provide guidance of axons of ganglion cells from retina
What is necessary for corneal induction
Pax6
What is necessary for the differentiation of the pigmented retina
- Stimulated by what
Otx2
-Stimulated by Shh
What axis is fixed first?
-Established by what gradients
Nasotemporal (anterior-posterior) axis
-Gradients of Ephrins and receptors
What axis is fixed second?
-Established by
Dorsoventral axis
-Antagonistic actions of Shh and BMP along with ventropin, Tbx-5, Pax2, and Vax2
The absence of eye, lack formation of optic vesicle
-Mutation
Anophthalmos
-Rax
Small eyeball or vestigial eyeball
Microphthalamos
Nonclosure of the choroid tissue of the iris during the sixth or seventh week resulting in its persistence
Coloboma iridis
Coloboma
Rathke’s pouch is an evagination from the roof of what?
What is its primordium for the anterior pituitary
Stomodeal ectoderm
-Adenohypophysis
First arch develops into ______ because of the lack of _____ gene expression
Jaws
Hox
Expression of what keeps arch 2 from differentiating into arch 1 and forming jaws
Hoxa2
Arch I nerve
CN V