Exam 2 Dev Bio

epiblast

top layer of cells

hypoblast

gets displaced by cells migrating in

formation of the yolk sac

1st tissue that gives rise to Red blood cells

along which axis does the neural tube form?

along the A-P axis

where does the neural crest form

between surface ectoderm and neural tube, then migrate out into bodyform

what does the neural crest form?

forms adrenal glands, heart pieces, facial bones, considered 4th germ layer

mesodermal derivatives

chorda, paraxial, intermediate, lateral plate

endoderm derivatives

branchial arches, aligned with interior pouches/tissue that form digestive tract linin

what do the branchial arches (derivative of __derm) form?

tissue for gas exchange (trachea, gills, lungs); vital glands (ex. thyroid)

pharangyeal endoderm forms

oral cavity/pharynx lining and gills

enteric nervous system

gut has its own neural network, wired with, but separate from, sympathetic nervous system

chordomesoderm

forms notochords and intervetebrial disks

paraxial mesoderm

forms head and somites, scleratome, arthrotome, syndetome, endotome

scleratome

cartilage and bone

arthrotome

ribs and vertebrate

syndetome

tendons

endotome

endothelium cells, dorsal aorta

dermatmyotome

skeletal muscle, dermis and skeletal muscle

axis elongation in zedbrafish

1. cell migration

2. cell division

3. presomitic mesoderm and notochord interaction

cell migration stage of axis elongation

NMP cells from DMZ migrate to progenitor zone

neuromesoderm progenitors (NMP)`

contribute to development of neural tube

dorsal medial zone

origination of bipotential NMPs

ectodermal derivatives

placodal ectoderm, neural ectoderm, neural crest

what concentration of WNT and BMP makes non-neural ectoderm

high levels of WNT and BMP

what concentration of WNT and BMP direct ectoderm to become neural ectoderm?

high WNT, 0 BMP

what concentration of WNT and BMP makes migratory neural crest cells

high WNT, little BMP

what concentration of WNT and BMP makes placodal ectoderm?

little WNT, THEN little BMP (sequentially)

products of surface ectoderm

hair, nails, sebaceous glands, olfactory epithelium, mouth epithelium, lens and inner ear

components of mouth epithelium

anterior pituitary, tooth enamel

what does neural crest form

peripheral nervous system

peripheral nervous system components

schwann cells, glial cells, para/sympathetic nervous system, adrenal medulla, melanocytes, glandular tissue, facial cartilege, derivative of teeth

epiboly

movement of epithelial sheets (spreading as a unit)

what causes epiboly?

cell division, cells changing shape, several cell layers

layers of epideermis

basement membrane, stratum basli, spinosum, granulosum, lucidum, and corneum

basement membrane

extracellular membrane and connective tissues

stratum basali

basal layer; mitotically active cells, act as STEM cell population

stratum spinosum

cells actively growing, migrating, ramping up keratin production

stratum granulosum

cells are alive, keratin starting to get built up

keratinocytes

cells in the stratum spinosum that make keratin

stratum lucidum

only in areas with thicker tissue (like soles of foot)

stratum corneum

dead skin cells at the top (not undergoing cell processes)

keratin

protein built up in cells that make skin impermeable

direction of mitotic division in skin

indicates whehter they will differentiate or remain STEM cell

if a cell is in contact with basement membrane

it remains a stem cell

basement membrane composed of

laminin

laminin

extracellular matrix protein

integrins

cell surface protein; ligand binds to laminin receptor

jagged

proteins on membrane of newly divided basal cells

what does the interaction of jagged and notch do?

forms keratinocytes and induces keratin production

tooth development in mouse

1. thickening of neural crest epithelium

2. ball of mesenchymal cells condense

3. cap of enamel knot forms

4. E and M layers diffrentiate

where is thickened epithelium in mouse teeth derived from

neural crest cells

why is the cap/enamel knot important

important signalling center

ameloblasts

produce enamel (epithelial)

odontoblasts

produce dentin (mesenchymal)

BMP

bone morphogenic protein

FGF

fibroblast growth factor

ectodermal appendages examples

feather, scales, claws, glands, coverings of antlers, horns, hooves

uropygial glands

oil gland near tail to preen feathers of water fowl

process of CNS development

1. neural induction

2. neuralation

3. proliferation, differentiation, migration

4. axon growth, guidance

5. target growth, guidance

6. target recogntion

7. synaptogenesis

8. plasticity

cranial placodes

thickenings in ectoderm that invaginate to form vital cranial structures

olfactory epithelium

thickens and invaginates in as a pit, as cells migrate through producing GnRH

rhombomeres

hindbrain has segments, collective expression of patterning genes (ie HOX)

dorsal-ventral patterning

positional identity to rhombomeres of spinal cord

interneuron function

connect neurons to each other

motor neuron target

muscle

dorsal pathway controls

sensation

ventral pathway controls

motor neurons

what does repositioning the notochord do? (move it experiment)

induces 2nd foreplate and get motor neurons form

dose dependent effect of SHH

these genes affect expression of other genes _ amount of time exposed to signal

what is the interaction between SHH and Pax 7?

SHH inhibits Pax 7

what is the interaction between SHH and Olig 2?

small amounts of SHH needed to trigger Olig 2, but NKX2 can inhibit Olig 2

What is connection between SHH and NKX2?

longer exposure (through time and dosage) of SHH encourages NKX2

what induces dorsal signaling for DV patterning

BMPs and dorsalin

what induces ventral patterning of neural development

SHH

White matter in spine

axon tracks

butterfly shape of spine

for sensory and mtoro tracks

where does all sensory info converge

dorsal root ganglia

where does motor info combine

ventral root ganglion

sensory and ventral dermatomes

corresponds with vertebra for info sharing with spine

what are the three zones of neuronal development in spinal cord and medulla

ventricular zone, mantle intermediate zone, marginal zone

the mantle intermediate zone is also known as

gray matter

marginal zone

white matter

how does spinal cord, cerebellum, and cerebral cortex differ in neuronal development?

more layer with increasing complexity

cerebellum migrating neuron layers

ventricular zone, marginal zone, internal granular layers, purkinje cell layer, marginal zone, external cell layer

cerebral cortex migrating layers

ventricular zone, sub ventricular zone, mantle zone, cortical plate, marginal zone, molecular zone

external granular layer

critical event in development of cerebellum where neural progenitor cells migrate to outer surface

internal granular layer

BMPs modify neural progenitors, sending them back up tube

purkinje neurons

only output neurons of cerebrellar cortex, emit SHH, forming 100,000 synapses with other neurons

asymmetric division of radial glia

mechanism to determine fate of cells

stages of synaptogenesis

1. intial contact - adhesion

2. formation of synaptic vesicles

3. stabilize synapse

adhesion in synaptogeseis

initiates formation of vesicles, receptors of neurotransmitters on post side

neuromuscular junction formation

1. inbuilt with ACh recetpros

2. production of aggrin stimulation concentration of ACh to increase by the axon

3. stimulates motor neuron to form active site

4. activity dependent firing will ensure motor neuron with best activity will fire more

neurotrophin

protein made by target neuron to attract axon

LIm family of transcription factors

play critical role in motor neuron specification

cardiac neural crest

form septum between pulmonary artery and aorta

cranial neural crest becomes

cart of jaw, bones of middle ear, odontoblasts, cranial nerves, face bones

otic vesicle

forms inner ear

role enamel knot plays in signalling

tooth shape and development of tooth

pre-placodal region divides into

individual placodes as regulated by local signals

eye field in anterior neural plate

initial formation of retina