Neuro Flashcards
transmitters: excitatory: moves the post-synaptic membrane ____ to threshold (aka ____) , uses _____ to do so
closer to threshold
aka depolarization
Na-K channels to do so
transmitters: inhibitory: moves post-synaptic membrane ____ from threshold (aka _____), uses _____ to do so
away from threshold
aka hyperpolarization
Cl- channels to do so
what are the 6 excitatory transmitters?
Ach, 5HT (serotonin), NorEpi, Epi, Dopamine, Glutamate
what are the 2 inhibitory transmitters?
Glycine and GABA
what are subgroups of neuropeptides? what do they do? what are the 3 specific kinds?
pain sensation and perception neuromodulators and neurohormones (modify the work of other NTs) 1. substance P 2. endorphins 3. enkelphans
refractory period: absolute vs relative
absolute: closure of inact. gates for Na+ will NOT open till the cell is FULLY repolarized (-70mV)
- takes up most of the curve
relative: starts when absolute is over and lasts through hyperpol.
there CAN be axn potential IF there is a big enough stimulus to bring it from more neg. status back to threshold
what is accomodation?
when the threshold is passed but no axn potential is produced. (when depol. closes Na+ channel inactivation gates…which can’t reopen till threshold of -70mV is achieved).
example: hyperkalemia: too much K+ = decreased drive inside cell, can’t get back to -70mV…. gates wont open = cardiac arrest
bigger nerve = faster or slower impulse?
myelination = faster or slower impulse?
bigger and myelin both conduct a faster impulse current
what are the nodes of ranvier?
breaks in myelin where axn potential is generated
how do gap junctions assist in electrical synaptic transmission ? what type of cells are these in?
allow signal to go straight through = faster impulse
these are in coordinated muscle cells: ventricles (cardiac) and uterus + bladder (smooth)
what are chemical synaptic transmitters?
inhibit or excite dependent on the NTs
what is the process that occurs at a synaptic junction of a motoneuron after the axn potential comes into the pre-synaptic terminal?
- ca+ channels open
- flow down conc gradient, synaptic vessels open and release NTs
- diffuse across cleft and bind receptors on the end plate
=change in membrane potential
somatic vs autonomic
both of the peripheral nervous system …
somatic: voluntary movements and involuntary reflexes- sensory and motor to the body
autonomic: viscera, smooth muscle, and glands
electroneutrality
MACROscopic neutrality
inside and outside the sell there is a balance of total pos and neg charge (cations and anions)
membrane potential is created by what type of movement?
MICROscopic movement of charged particles (Na+, K+, Ca+, Cl-, HCO3-)
what is resting membrane potential? what are freely diffusing here? what is the Na/K pump doing?
period of time when excitable cells are NOT transmitting signals
K+ and Cl- freely diffusing
Na/K ATPase pump 3Na+ out and 2K+ in = negative inside cell
if there is a potential difference across the membrane, there will be a changed rate of diffusion of ____
charged solute
if there is no potential difference across the membrane, the diffusion of ____ will do what?
charge solute
will create a diffusion potential
conc. of solute does or does not change w/ movement of ions across the membrane
DOES NOT
what are our types of excitable tissue?
nerves and muscles
changes in membrane potential will cause axn potential (depol to repol)
what does our glandular tissue do with a change in membrane potential?
hormones secretion and other functions
____brings opposites closer together and ____ brings opposites farther apart
depolarization
repolarization
what is it when the potential or MORE neg. than the resting membrane potential?
hyperpolarization
axon vs dendrite
axon: away from the cell
dendrite: toward the cell
afferent vs efferent
afferent: sensory to CNS
efferent: relay motor impulse to effector neuron
effector
peripheral tissue that reacts by contraction or secretion (exit CNS)
schwann vs glial
both neuroglial cells
schwann: PNS support cell (highly lipid soluble)
glial: CNS support (4 types- astrocytes, microglial, oligoDs, ependymal)
what are tracts?
white matter (axons) that come out of grey matter "clumps" aka highway of the axons
afferent has ____ cell body and ____ axons
1 cell body and 2 axons (pseudounipolar)
what are the 3 layers of each peripheral nerve? (deep to most superficial?)
- endoneurium
- perineurium
- epineurium
ganglia vs nucleus?
both grey matter (thinking, info-processing area)
ganglia: PNS
nucelus: CNS
cell column vs cell tract
column: cell bodies inside -grey matter
tract: axons inside -white matter
can a neuron regenerate?
NO
what are the three jobs of the schwann cells?
- protection
- metabolic support
- inc. conduction of velocity
all brain cancers that we have are made out of what?
glial cells of the CNS
satellite cells do what?
protect cell bodies from surrounding connective tissue framework
transport of contents in cell body through cytoplasm to axons…. neurosecretory granules vs proteins and nutrients…which is fast and which is slow?
fast: neurosecretory granules
slow: proteins and nutrients
what do neuroglial( “glial”) cells do?
supporting cells of CNS
- the “glue” that sticks everything together
- communication of neurons
- capable of division, grow fast and multiply
what are the 4 types of glial cells
- oligodendrocytes
- astrocytes
- microglial cells
- ependymal cells
what do oligodendrocytes do?
they form the myelin in the CNS, cover multiple axons
what do astrocytes do? 5 parts
- stick to cells, vessels and nerves
- make up the BBB
- maintain conc. of ions and NTs
- metabolite transport
- after injury…cell bodies fill their cytoplasm w/ fibrous astrocytes and become scar tissue
what do microglial cells do?
phagocytic
what do ependymal cells do?
lines ventricular system and produce CSF
3 types of “brain” tumors
- primary intracranial of neuroepithelial type (neuroglial, oligoD, ependymomas, astrocytoma (80%)
- neuronal tumors : medulloblastoma (infants and children from primitive cell type in the cerebellum)
- primary intracranial tumor in cranium but NOT of brain tissue (meningioma, CNS lymphoma, metastatic cancer)
inward vs outward current? (membrane potential)
inward: positive flows into cell
outward: positive flow out of cell
what is threshold potential?
membrane potential when depolarization is inevitable
“motoneuron” is upper/lower motor neuron?
lower motor neuron
overshoot vs undershoot?
overshoot: axn pot. part where membrane pot. is positive
undershoot: hyperpol. after-potential: axn. potential part where membrane potential is more neg. (than at rest)
what is the refractory period?
when another axn pot. can NOT be initiated
what part of the graph correlates with the activation gates opening?
upstroke: gates open, Na + flow in, causes the upstroke
what part of the graph correlates with inactivation gate closing?
upstroke ENDS …then K+ channels open
how does lidocaine work in regards to membrane potential?
blocks voltage-gated Na+ channels = blocked impulse
= numbness
what are the three chief characteristic of axn potentials?
- stereotypical size and shape:… if normal, each given cell type is identical
- propagation: axn potential at one site causes depol at other sites
- all or nothing response: if excitable cell depolarizes to threshold, axn potential WILL happen
conductance of K+, Cl- and Na+
K+ and Cl- are high (always flowing)- conc. gradient and open channels
Na+ is low (now open gate = no inward flow)
