Exam 1 Flashcards
somatic vs autonomic motor division
somatic: skeletal muscle, autonomic/visceral: smooth, cardiac muscle + glands
both part of peripheral nervous system
ganglia
accumulations of nerve cell bodies in pns
gray matter
cell bodies and neuropil in brain and spinal cord
white matter
axon tracts
nucleus
local accumulation of neurons w roughly similar fins
cortex
sheetlike array of nerve cells
commissures
tracts that cross the midline of the brain
columns
sensory tracts of dorsal spinal cord
autonomic path
autonomic motor neurons in brainstem and spinal cord (preganglionic neurons) -> peripheral motor neurons in autonomic ganglia -> these innervate smooth muscle
sympathetic vs parasympathetic organization
sympathetic: ganglia are in vertebrate
parasympathetic: ganglia are near organs
enteric system
small ganglia and individual neurons in gut wall
neural system characteristics
unity of fxn, representation of specific information, subdivision
computational vs topographic maps
topographic: like vision, point to point correspondence
computational: not like that
cre/lox system
cre recombinase is introduced to mouse genome through homologous recombination, cuts loxP sequences
creERT method
cre haș an estrogen receptor that can only be activated by tamoxifen, allows temporal control
gastrulation
single layer of cells -> multiple germ layers
germ layers
ectoderm, mesoderm, endoderm
notochord
cylinder of mesodermal cells that condenses at midline, generated at primitive pit. axis of symmetry
neuroectoderm
ectoderm above notochord, gives rise to nervous system
neurulation
notochord sends signals to tell above cells to differentiate into neuroectodermal precursor cells. midline ectoderm hardens into neural plate
neural tube
gives rise to entire brain and spinal cord, formed from neural plate
neural crest
where edges of folded neural plate come together, give rise to a bunch of neurons and glia, cartilage, bone, etc
sections of neural tube
prosencephalon (cane hook), mesencephalon, rhombencephalon
prosencephalon forms
telencephalon, diencephalon, and optic vesicles -> eventually all forebrain
rhombencephalon forms into
mesencephalon and myelencephalon
neuromeres
repeating units in neural tube -> eventually cerebellum
how genes
divide embryo into segments
retinoid acid
inductive signal
some neural inducer things
bone morphogenetic proteins, sonic hedgehog, fibroblast growth factor
noggin and chordin
endogenous antagonist which block bone morphogenetic proteins so that ectodermal cells can stay neurons
sonic hedgehog what sit important for
closing neural tube, establishing identity of neurons in spinal cord
neuroblasts
immature nerve cells
delta ligands and notch receptors
delta ligands send signals to notch receptors in adjacent cells, liberating notch intracellular domain
basic helix loop helix neurogenic factors
local delta notch signaling -> downregulation of delta in most cells, but up regulation in some. in these, bhlh is unregulated and cell becomes primed for neuronal differentiation
neurogenesis process
lots of lil neurites -> one is picked as axon and rest become dendrites
growth cone
structure at tip of extending axon which helps it explore and determine direction of growth
lamellipodium
sheetlike expansion at tip of growth cone
filopodia
fine processes that extend from lamellipodium, which rapidly form and disappear
actin skeleton vs microtubule skeleton role in growth cone motility
actin: changes in shape of tip
microtubule: elongates axon
both controlled by (de)polymerization
molecules which influence axon growth
extracellular matrix molecules, ca independent and dependent cell adhesion molecules, and ephrins
extracellular matrix cell adhesion molecules include… + properties
laminins, collagens, fibronectin
all found in ecm and create durable surfaces
receptor for ecm molecules
integrins
where are CAMs and cadherins found + why r they unique
on growth cones, growing axons, and surrounding cells
they are both ligand and receptor
ephori function
cell-cell recognition
netrins
proteins that attract axons, esp helps with those crossing the midline
slit and robo
slit = secreted factor, robo = receptor; help axon from coming back over the midline by terminating sensitivity to netrin once its crossed. slit also helps with dendritic branching
semaphorins
chemorepellents which cause growth cones to collapse and axon extension to stop. also can serve as a chemoattractant for dendrites
brain derived neurotrophic factor
promotes dendritic growth and branching
dendritic tiling
dendrites are repelled from other dendrites (including their own)
modulated by dscam1
chemoaffinity hypothesis
each destination cell and ganglion cell has a specific tag which matches them
proven to be more of a gradient of affinities
neuregulin
regulates expression and localization of postsynaptic receptors
neurexins and neuroligins
neurexins = presynaptic
neuroglins = postsynaptic
promote adhesion in the synapse, help localize synaptic vesicles, docking proteins, receptors, etc
