CNS Part 2 Flashcards
Basic functional unit of CNS, how work is done.
Neuron
Language of neurons
Action potentials
Structural support or CNS
Neuroglia
What maintains and buffers ECF, regulates electrolytes, and is involved in signal transmission
Astrocytes
What produces myelin
Oligodendroglia
What in CNS is involved in Immunity and presents antigen to T cells
Microglia/ latent phagocytes
What lines ventricles and produces CSF
Ependymal cells
What produces myelin in PNS.
Schwann cells
1 Schwann cell per ___. 1 ___ can myelinate several axons in CNS
Axon. Oligodendrocyte
What is structural support in PNS
Satellite cells
Input directly goes to __ or to __
Dendrites or soma
Impulses only travel in one direction because of what
Refractory period
Excitatory comes on __, inhibitory mainly on ___. But there are exceptions
Dendrite, soma
Axon hillock is dense in __ __. Easier to reach thresholds here than __, which needs more __
Sodium channels, soma, inputs
Inter neurons have __ axons
Small
Unipolar neurons more common in what
Intervertebrates
Pseudo unipolar neurons found in __ __ __, __ neuron. Axon comes straight out and goes to __ __ directions
Dorsal root ganglion, sensory. Two different
__ neurons common in nose and eye, sensory organs
Bipolar
___ neurons are motor neurons
Multipolar
Major neuron types of cerebral cortex: __ cells and __ or __ cells
Pyramidal
Stellar or granule
Pyramidal cells are __% of cerebral cortex
__ amino acid: __ or __
75
Excitatory, glutamate, aspartate
Stellate or granule cells are __% __
___ amino acid: __ or __
Most are ___: ___
25, interneurons,
Excitatory, glutamate or aspartate
Inhibitory, GABA
Anesthetic agents work by enhancing what
GABA
GABA works by passing ___, brings __ inside of cell. ___ cell further
Chloride, negative, depolarizes
__ ___ get things from cell body to pre-synaptic terminal
Calcium microfilaments
__ and __ can move quickly because of microfilaments
Mitochondria and vesicles
__ move slowly
Proteins
2 major proteins: ___ from spinal cord to foot. __ moves proteins back up from axon terminus to cell body. Both are __ and use __
Kinesins
Dynein
ATP
Microtubules
Rely on __ to keep ions and neurotransmitters in balance. ___ critical for normal neuronal function
Neuroglia
Astrocytes
___ speed conduction
__ can produce glial scars, which is why people with __ __ __ don’t recuperate
Oligodendrocytes
Astrocytes, spinal cord injury
RMP __. Depolarize __-__ mV to reach __ mV threshold. __ or __. All action potentials are the same __. Na opens and shuts __. Refractory period __ and depends on __. Need even more __ to achieve hyperpolarization.
-70. 10-20. -50. All or nothing. Size. Fast. Varies, neuron. Depolarization
In relative refractory __ channels are open
In absolute refractory __ channels are closed
K
Na
__, __, and __ look the same on a chart as a phenomenon
Voltage, conductance, current
K stops leaking because of __ gradient
Electrical
In unmyelinated have to __ depolarize. Requires a lot of __ and running of __ __ to restore gradient, not efficient
Sequentially, ATP, Na/K
Because membrane is thin can lose __ into membrane in unmyelinated. Have to overcome __
Myelinate on decreases __ and increases ___. Use less __
Charge, capacitance
Capacitance, resistance. ATP
Myelinate on restricts action potential generation to __ __ __
Nodes of ranvier
In local anesthetics unmyelinated nerve will have axon __
In myelinated will only be touched at __ and need to cover __ to have a block
Covered
Node, 3
ATP pumps on myelinated found where, on unmyelinated found where
Nodes of ranvier
Along entire length
Myelinate on benefits: fast ___, __ __ processing, __ advantage
Reflexes, complex mental, metabolic
Withdrawal reflex takes place where
Myelinated axon
Oligodendrocytes CNS Schwann cell myelination # of cells
Oligodrendrocytes- myelinates many axons with one cell in CNS
Schwann cells myelinate with one cell per axon in PNS
A alpha sensory fiber. Size compared to B and C. Conduction velocity. Supplies receptors: __ __ spindles, __ __ organ. ___ fiber
Bigger than b and c. Fast because big. Primary muscle, Golgi tendon. Motor
A beta fiber. __ compared to a alpha. Still ___ in velocity. supplies receptors: __ muscle spindles, skin ___
What kind of fiber
A little slower, fast, secondary, mechanoreceptors
Sensory
A delta fiber: __ function. __ pain conducted. Supplies skin ___, __ receptors, and ___. These are myelinated or not. This is the __ surgical pain
Important to who
Sensory, fast, mechanoreceptors, thermal, nociceptors
Myelinated. Initial. CRNA
Easiest to block __ and __ fibers
B and c
C sensory fibers: __ __ fibers. Myelinated or not. __ pain. Receptors are skin __, __ receptors, and __. On __ of nerve fiber
Slow pain, not, mechanoreceptors, thermal, nociceptors. Outside
A alpha motor fiber imp in __ __. Receptors in __ __ muscle fibers
Motor movement, extrafusal skeletal
A gamma y motor fibers imp for __ and __. Receptors are __ muscle fibers
Balance and tone. Intrafusal
B motor fibers. __myelinated. Receptor on __ __ fibers
Lightly, Preganglionic autonomic
C motor fibers. __myelinated. Receptor on __ __ fibers
Not. Postganglionic autonomic
__ and __ fibers out outside of nerve fiber. __ __ outside. __ __ and __ __ on inside
B, C. A delta.
A alpha and A beta
___ neuron-neuron junction present in __ __ (electrical) and __ mediated (chemical)
Classic, gap junctions, neurotransmitter
3 types of synaptic signaling
Neuron neuron
Neuron glial
Extra synaptic
In extra synaptic signaling NTs released from synapses act on receptors that are __ of the __ area
Outside, synaptic
Gap junctions
- __ __ pathways that allow current to flow
- allows exchange of __ __ between cells
- __ and __
Low resistance
Small molecules
Fast and bidirectional
Gap junctions
- __ of network activity and __ __ neurons
- regulated by __, __ __, __, and _ _ coupled receptors
Synchronization, electronically coupled
Voltage, intracellular pH, calcium ion, G protein
Gap junctions aren’t primary means of ___
Connexons are ___
Communication
Channels
Chemical synapses
A lot of __ here to restore ionic gradient. __ going into cell requires removal and a lot of __
Mitochondria, calcium, ATP
Chemical synapses
Connections mainly on __ only a few on __ __
Delay when chemicals travel __ __
Dendrites, cell body
Across cleft
Synaptic transmission
- Action potential is propagated to the __ terminal which __
- __ channels __ in response to depolarization
- Increased __ conc in presynaptic micro domain promotes __ of vesicles containing neurotransmitter within plasma membrane
Presynaptic, depolarizes
Calcium, open
Calcium, fusion
Synaptic transmission
- NT binds __ __ receptors stabilizing the __ confirmation of the receptor
- Within __ NT is __ from synaptic cleft
Post synaptic, active
Milliseconds, cleared
Synaptic transmission
- ion flow dependent on 2 gradients:
- open or closed confirmation of ion channel results in __ or __
Concentration and voltage
EPSP, IPSP
___ of NT is primary, ___ is secondary to reduce NT conc in synaptic cleft
Reuptake, degradation
Agonists stabilize __ confirmation channel
Antagonists __ __ from binding and support __ confirmation
Open
Prevent agonists, closed
Acetylcholine or cholinergic synapses stopped by ___
Most others such as norepi and glutamate stopped by __
Degradation
Re uptake
Gaseous neurotransmitter
NO
Fusion of synaptic vesicle that has NT with presynaptic membrane occurs at __ sites called __ __
Specific sites, active zones
Active zones rich in calcium channels= micro domain __ in cystolic ca with __ __
Increase, action potential
Docking, priming, and fusion process involve ___
SNARE: soluble, n-ethyl, attachment receptor protein
V snares: __ __
T snares: target __ __ __
Vesicle membrane
Presynaptic plasma membrane
__, __, and __ zip together bringing the vesicle membrane and presynaptic membrane into close proximity
Synaptobrevin, syntaxin, and snap-25
___ appears to be the calcium sensor in vesicular release
Synaptotagmin
Vesicular release occurs with voltage gated __ channels __. What inhibits these
Calcium, open
Botulism
Calcium entry and exit mechanisms: calcium __, __ gated ca __, __gated ca _, __/__ exchanger
Pump, ligand channel, voltage channel, Na/ca
Ca has a crucial role as mediator of __. It is at the base of __-__ coupling
Secretion
Excitation secretion
Ca concentration gradients are __
Extracellular __-__ milimolar
Intracellular __-__ nanomolar
Huge
1-2
10-50
__ gated ca channel can be blocked by different drugs
Ligand
Inactivation channel type: inactivation. Speed. L, P, N, T, Q/R
None to little Slow Slow Rapid Slow
Antagonist channel in voltage gated ca channel: l, p, n, t
DHP
DHP and spider venom insensitive
Conotoxin and dhp insensitive
Nickel ions
Activation of calcium channels L P N T Q/r
Strong depolarization Strong depolarization Strong depolarization Near resting potential Strong depolarization
Location of voltage gated calcium channels L P N T Q/r
Skeletal, cardiac, muscle, brain, neuroendo Presynaptic Presynaptic Cardiac muscle and neuron cell body Cerebellum granule cells
Function of voltage gated calcium channels L P N T Q/r
Varied Transmitter release Transmitter release Rhythmic potentials Transmitter release
Criteria to be a neurotransmitter:
Present in __ __
Cell must be able to __ the subtance
Released upon __ of presynaptic membrane
Specific __ on postsynaptic membrane with or without __ locations
__ and __ don’t follow these rules
Presynaptic terminal Synthesize Depolarization Receptor, extra synaptic Hormones and peptide transmitters
Non peptide transmitters/classic neurotransmitters
- synthesized and packed in __ __
- synthesized in __ form
- usually in __, __ vesicles
Nerve terminal
Active form
Small, clear
Non peptide/classic neurotransmitters
- released into __ __
- action of many terminated because of uptake by presynaptic terminals by __ powered __ transport
- action has __ latency and __ duration
- synaptic cleft
- Na, active
- short, short
Peptide transmitters
- synthesized and packed in __ __, transported to nerve terminal by __ __ transport
- active peptide formed when it is __ from a much larger __ that contains several neuro peptides
- usually present in __, __ dense vesicles
Cell body, fast atonal
Cleaved, polypeptide
Large, electron
Peptide transmitters
- may be released by some __ in the __ cell
- there may be no _- __ synaptic structure
- action terminated by __ or the peptide __ away
- action may have __ latency and may __ for many __
- distance, postsynaptic
- well defined
- proteolysis, diffusing
- long, persist
Small molecule/classic NTs
Class I: ___
Class II: __ __, 5
Acetylcholine
Biogenic amines: norepi, epi, dopamine, serotonin, histamine
Small molecule NT
Class III: __ __, 4
Amino acids
GABA, glycine, glutamate, aspartate
GABA- mostly ___. Most anesthetics __ GABA activity or work on these receptors
Glycine- imp in __ __. __. Not many drugs __ it specifically
Glutamate and aspartate are __
Inhibitory. Increase
Spinal cord. Cotransmitter. Target
Excitatory
Neuro peptide/peptide transmitter classes 4
Hypothalamic releasing hormones, pituitary peptides, peptides that act on gut and brain, from other tissues
Peptide transmitters: hypothalamic releasing hormones 3
Thyrotropin releasing hormone
Luteinizing hormone
Somatostatin/growth hormone inhibitory factor
Peptide transmitters: pituitary peptides
__, __-endorphin, __melanocyte stimulating hormone, __, __ hormone, __, __ hormone, __, __
ACTH Beta, Alpha Prolactin, Luteinizing Thyrotropin, Growth hormone Vasopressin, oxytocin
Peptides that act on gut and brain \_\_ enkephalin (\_\_ peptide), \_\_ enkephaline (\_\_ peptide), \_\_ \_\_, \_\_, \_\_, \_\_ intestinal polypeptide VIP, \_\_ growth factor, \_\_-derived neurotropic factor, \_\_, \_\_, \_\_
Leucine, opioid Methionine, opioid Substance P, gastrin, cholecystokinin Vasoactive, nerve, brain Neuro tension, insulin, glucagon
Peptides from other tissues: angiotensin __, __, __ peptides, __
II, bradykinin, carnosine, sleep, calcitonin
Gaseous NTs
Are not released from __
__ __ and __ __
Vesicles, nitric oxide, carbon monoxide
Gaseous NTs released from __ __ __
Pre synaptic cell
How gaseous NTs work
__ or __ come into cell and cause __ increase. __ or __ stimulates _ __ coupled receptor. Increases ca release which binds __. Goes to __ __ __. Converts __ to __ __. Converts __ to __. Decreases _ entry.
AP or NT, Ca, ach or bradykinin
G protein, calmodulin, nitric oxide synthase,
GTP to cGMb, calcium
Glutamate responsible for __ __
Too much glutamate for too long can cause __. End effect __ or __. Too much __ and no __ to pump it out
NT recycling
Apoptosis. Stroke or ischemia. Calcium, ATP
___ takes up glutamate. Sits on __ and __ nerves. Have them on __ cells. __ converts glutamate to glutamine. Transfer glutamine back to neuron without causing __. Rely on __ to keep glutamate levels normal
EAAT. Pre and post synaptic.
Glial. Astrocytes. Cytotoxicity. Astrocytes.
Acetylcholine broken down by __ in synaptic cleft
__ transported back to axon terminal and used to __ __ ach
Acetylcholinesterase
Choline, make more
EPSP or IPSP occurs when __ binds to a __ __ receptor.
__ __ channel for fast transmitting
__ __ __ __ for slow transmission
NT, post synaptic
Ligand gated
G protein coupled receptor
In G protein receptor when alpha beta and gamma are together channel is __
Inactive
Post synaptic responses to NT
-ion current flows then the direction of flow depends on __ __ of __ __
Electrochemical gradients, per meant ions
Ix= gx X (Vm - Ex)
What I, X, Vm, Ex, and g are
I is current X is an ion Membrane potential Vm Ex is Nernst potential How channel conducts moving through a membrane
Miniature end plate potential: __ depolarizations of postsynaptic membrane. Reflect __ release of a __ synaptic vesicle. Too __ to reach threshold, _ action potential occurs
Small,
Spontaneous, single, small
No
EPSP: __ __ flux. Decreased __ influx or __ efflux. Change in receptor __ or enzymatic or metabolic activity (__ effect)
Increased Na. Cl. K.
Expression. Delayed
IPSP: __ __ influx or __ efflux. Can be __ or __ __. Change in receptor expression or enzymatic activity w __ effect
Increased Cl, k. Pre or post synaptic
Delayed
Spatial summation
Multiple synapses firing causing AP to occur
Temporal summation
Same axon firing repeatedly
Facilitation
Have some synapses. Not enough to get over threshold. A few more come in and threshold achieved
Divergence
Multiple branches come into one single tract
Convergence
Single source branches into several branches
__ __ helps coordinate motor movements. Releasing __ inhibits it
Reciprocal inhibition
GABA
Reverberatory circuits can __ __ on themselves and even __ or __ signal. Imp in __ __ __
Feed back, amplify, inhibit
Short term memory
Majority of synapses are ___
Alkalosis in isf __ neuronal ___
Acidosis __ neuronal __
Dendritic
Increases, excitability
Depresses, activity
Hypoxia severely __ neuronal __
Drugs can increase and decrease __
Decreases, excitability
Excitability
What can increase chances of a seizure
Alkalosis