Neural anatomy Flashcards
what process does an injured neuron undergo
Wallerian degeneration: the axon portion distal to the injury degenerates and the proximal portion contracts in order to regenerate (in PNS neurons)
what six functions do astrocytes accomplish
provide structure, repair, K+ metabolism, recycling of neurotransmitters, component of BBB, glycogen stores buffer
what is the molecular marker for glial cells
GFAP
what is reactive gliosis
proliferation of astrocytes in response to neural injury
which glial cell cannot be stained by Nissl
microglia
what does myelin do to the space constant (length constant) and conduction velocity
increases space constant and conduction velocity
which cell myelinates many neurons and which can only myelinate one neuron per cell
one oligodendrocyte myelinate many neurons (~30) while one Schwanna cell only myelinates one neuron
name three diseases in which oligodendrocytes are damaged/ dysfunctional
multiple sclerosis, PML (progressive multifocal leukoencephalopathy), leukodystrophies
in what autoimmune disease are Schwann cells destroyed
Guillain-Barre syndrome
what’s the most common type of schwannoma
accoustic neuroma, located in internal accoustic meatus (CN 8) –> tinnitus and hearing loss
what condition is bilateral accoustic neuroma associated with
neurofibromatosis type 2
name the two kinds of free nerve endings and their characteristics
C- slow, unmyelinated
A delta- fast, myelinated
what do free nerve endings sense
pain and temperature
what do Meissner’s corpuscles sense and where are they found
dynamic touch, fine/ light touch, position sense
found in glabrous (hairless) skin
where are Paccinian corpuscles found and what do they sense
found in the deep skin layers, ligaments and joints
sense vibration and pressure
where are Merkel discs found and what do they sense
basal epidermis layer of skin and in hair follicles;
they sense deep static touch (sharp edges), pressure, and position sense
what do the endoneurium, epineurium and perineurium surround, respectively
endoneurium- surrounds a single nerve fiber
perineurium- surrounds a fascicle of nerve fibers
epineurium- surrounds an entire nerve along with its vasculature
which nerve sheath has to be rejoined when reattaching a limb
perineurium
where is norepinephrine produced
locus ceruleus of the pons
where is serotonin (5-HT) produced
Raphe nucleus
where is dopamine produced
ventral tegmentum and substantia nigra pars compacta
where is acetylcholine produced
basal nucleus of Meynert
where is GABA produced
nucleus accumbens
what is the neurotransmitter profile for Huntington’s
decreased acetylcholine and decreased GABA
increased dopamine