L15: Nervous Tissue Flashcards
list the stages of neural development
- neural plate
- neural folds
- neural tube
- neural crest tissue
list derivatives of neural tube
- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
3 histogenesis components of neural tube
- pseudostratified epi
- cortical plate
- marginal layer
neuroglial cells ?
non-conductive cells that support and protect entire nervous system
hold together system
cortical plate
future gray matter
marginal layer
axons
future white matter
nerve tissue characteristics
- irritability
- conductibility
- cellular components
- neurons
nerve tissue irritability
tissue specialized to receive stimuli
nerve tissue conductibility
tissue specialized to transmit impulses
cellular components of nerve tissue
neurons
neuroglial cells
neuron functions
- -conduct impulses
- -structural and functional unit of nervous system
neuron parts
cell body = soma
dendrites
axon
terminal boutons
neuron cell body
- contains nucleus
- Nissl bodies
- extensive RER
- mitochondria
- lipofuscin granules
- ligand gated channels and local potentials
neuron cell body microtubules
called neurotubules
intermediate filaments = neurofilaments
lipofuscin granules
- -formed from lysosomes
- -accumulate w/ age of neuron
gray matter
cells bodies, dendrites and unmyelinated axons
white matter
myelinated axons
dendrites
- conduct local potentials
- contain organelles
- dendritic spines
- branching
- ligand gated channels
axon hillock
origin of axon
no Nissl
associated w/ generation of ap (lowest resting potential)
axon
- voltage gated channels
- conduct ap
- mito and microtubules
- telodendrites w/ synaptic vesicles
- presynaptic membrane
- can be myelinated
classification of neurons due to function
- sensory or afferent
- motor or efferent
- interneurons
afferent neurons
sensory
transmit sensory info from receptors to cns
efferent neurons
motor
transmit motor info from cns to muscles/glands
somatic motor neuron
innervate skeletal muscle
autonomic motor neurons
innervate glands, cardiac and smooth muscle
divided into para or sympathetic neurons
interneurons
transmit impulses within cns and between sensory and motor neurons
classifying neurons by number of processes
- multipolar
- bipolar
- pseudounipolar
multipolar neurons
most common type
have a single axon and multiple dendrites
bipolar neurons
have 2 processes, one at each end of the spindle shaped neuron
associated w/ special senses such as smell and sight
pseudounipolar neurons
single process from the cell body that bifurcates into a central process
found in ganglia alongside spinal cord
classification of neurons by length of axon
- golgi I
2. golgi II
golgi I neurons
neurons w/ long axons that leave the gray matter they are a part of
golgi II neurons
neurons w/ short axons which ramify thru the gray matter
bundle of axons in pns
nerve
bundle of axons in cns
tract
ganglion
aggregation of cell bodies and dendrites in pns
nucleus
aggregation of cell bodies and dendrites in cns
epineurium
a thick fibrous coat that covers an entire nerve
supplied by blood and lymphatic vessels
type I collagen and fibroblasts
perineurium
dense CT, covers bundles of axons within nerve
epithelial-like fibroblasts on inner surface
blood nerve barrier
perineurium fibroblasts
- -joined by tight junctions
- -zonula occludens
- -permeable barrier
- -this layer has to rejoined in surgery to reattach a limb
blood nerve barrier
endothelial cells of vessels are also linked by tight junctions
endoneurium
thin layer of reticular CT, surrounds individual fibers and schwann cells
type III collagen
channels on axon
K channels
voltage gated Na and Ca channels
where are dense bodies found?
presynaptic membrane
anterograde direction
from cell body to distal end of axon
retrograde direction
from axon toward cell body
anterograde mvt
- kinesin
- can be slow, intermediate or fast
- slow - 2 systems: SCa or SCb
SCa system
anterograde transport of preassembled microtubules and neurofilaments