Glossary of Week II - more nervous system basics
Other Decks By This User
- Which cranial nerves have components that lie outside the CNS?
- III, VII, IX and X
- List the three connective tissue sheaths found in a peripheral nerve from the outside in.
- 1. Epineurium-surrounds nerve
2. Perineurium - surrounds nerve fascicle
3. Endoneurium - surrounds individual exon
- Which CT layer of the nerve behaves like a blood-nerve barrier?
- The Perineurium
- Do the CT sheaths surrounding the nerve have a blood supply or are they avascular?
- They have a blood supply
- There are two distinct areas seen in a myelinated axon. name them and describe which cellular side they are on.
- 1. major dense line - cytoplasmic side (dark due to squished proteins in cell)
2. intraperiod line - extracellular side
- What are the 2 main proteins found in myelin of peripheral nerves?
- 1. MBP (myelin basic protein)
- Charcot-Marie-Tooth disease is a mutation of what? (mutated thing pertains to myelin)
- mutation of the Po protein
- What is the analog of Po in the CNS? What about MBP?
- PLP (proteolipid protein)
MBP has no analog; it is present as itself in the CNS
- define the following nerve-nerve synapses: axodendritic, axosomatic, axoaxonic, dendrodendritic
- axodendritic: axon synapses on dendrite
axosomatic: axon synapses on soma (cell body)
axoaxonic: axon synapses on another axon
dendrodendritic: dendrite synapses on another dendrite
- List the 3 types of ganglia
- 1. sensory
- There are 2 types of sensory ganglia. What are they?
- dorsal root ganglia
- autonomic ganglia are characterized by _________ (multi/uni/pseudouni polar) neurons.
- In what type of ganglia are neuron-neuron synapses found?
In what type of ganglia are no neuron-neuron synapses found?
- Found in autonomic ganglia
not found in sensory ganglia
- * What type of nerve cell damage results in cell death?
* What type of nerve cell damage results in regeneration?
- * Damage to the perikaryon results in cell death
* Damage to the axonal processes can result in regeneration
- What are the three findings observed with perikaryon damage?
- 1. chromatolysis
2. eccentric nucleus
3. perikaryon swells
- Define primary and secondary degeneration. Where does this occur?
- occurs in the axon after damage.
1. primary degeneration - degeneration of axon proximal to cut. (minor)
2. secondary degeneration - degeneration of axon distal to cut (complete)
- T/F: Schwann cells do not degenerate when the axon they are associated with degenerates.
- FALSE. Schwann cells degenerate along with the axon.
- What happens to the endoneurium after axonal damage? Why is this critical for regeneration?
- The endoneurium remains as a hollow tube and is now called the endoneurial tube. Schwann cells eventually proliferate and fill the tube.
- What are Bugner Bands? What is their function?
- endoneurial tubes filled with Schwann cells. Axon sprouts grow along these bands.
- Distinguish between inter- and intra- cellular signalling.
- intercellular - between cells
intracellular - within cells (from one end to another)
- What are the advantages of utilizing electrical intracellular transport vs. the other types of transport?
- FAST transmission
MODIFIABLE - can increase or decrease signal very easily
diffusion and transport are slow mechanisms and are not modified easily.
- neuronal electrical potentials are dependant on 2 things:
- 1. DIFFERENT ION CONC. on the inside and outside
2. SELECTIVE PERMEABILITY of the plasma memb. to different ions
- the electrochemical gradient is formed by two separate forces. what are they?
- 1. concentration gradients
2. electrical charges
- when determinig the voltage potential of a neuron, what is the reference point?
- the outside of the neuron is assumed to have a charge of 0.
- *What is the resting membrane potential for most neurons?
*What does this mean in regards to charge differences across the membrane?
- -60 to -75 mV
*the inside of the cell is more negative than the outside.
- what is the difference between an ion channel and an ion transporter?
- *ion channel - passive, specific; ions flow down concentration gradient
*ion transporter - active, specific; ions move against concentration gradient & create gradients
- which ion is responsible for maintenance of the resting membrane potential?
- K+ (flows out of the cell leaving the inside very negative)
- At RMP: which ions are very permeable? which ions are not?
- Very permeable: K+, Cl-
Not: Na+, Ca++
* K+ and Cl- follow concenration gradient
- T/F: at electrochemical equilibrium K+ is moving outside of the cell
- FALSE: by the time electrochemical equil. is reached the [K+] on the inside and outside are equal.
- the equilibrium potential of K+ is -120 mV. Why is the RMP of a neuron only -60 mV?
- This is due to a slight influx of Na+ that makes the RMP more (+)
- What is the neuron membrane potential of Na+?
- +56 mV
- What are two types of graded potentials (which are a subcategory of slow potentials)?
- 1. Spatial
- Which ion has the greatest influence on the RMP? How about the AP?
- RMP -> K+
AP -> Na+
- in an AP, what phases does Na+ control and what phases does K+ control?
- Na+ controls: rising phase and overshoot phase
K+ controls: undershoot phase and termination
- What [exactly] is the factor that initiates the AP?
- an increase in Na+ permeability; hence Na+ rushes into the cell
- Describe the membrane permeability changes throughout the AP.
- Rising and Overshoot phases -membrane very permeable to Na+
Undershoot phase - Na+ permeability turned off, K+ perm. increased
Termination phase - K+ permeability decreases and cell returns to resting state
- Describe the changes in the voltage gated ion channels during an AP.
- 1. RMP - both closed
2. early depolarization - Na+ channels open
3. later depolarization and early hyperpolarization - Na+ channels inactivated; K+ channels open
4. later hyperpolarization - both closed, return to RMP
- Why is there a refractory period after an AP?
- Na+ channels take a while to "reset."
- What is essential for neurons to maintain RMP?
- ATP to run their Na+/K+/ATPases
- T/F: an AP degrades as it moves along an axon.
- FALSE: an AP does not degrade as it moves down the axon. An AP in one area induces an AP in another area, kind of like passing a baton in a relay race.
- Why does an AP not spread in both directions down the axon?
- The refractory period from where the AP just came from prevents that.
- in what part of a neuron does the AP usually start?
- the axon hillock
- is passive current flow fast or slow?
- fast: it is almost instantaneous and is used between the nodes of Ranvier.
- Which is faster: saltatory conduction or sequential conduction?
- saltatory conduction. sequential conduction occurs in an unmyelinated axon.
- List the 3 types of ion channels.
- 1. voltage gated (only open within a certain voltage range)
2. ligand gated (ion channel opened by specific chemical signal)
3. stretch & heat activated (sensory receptors that generate receptor potentials)
- What are the two active transporters that return a cell to RMP?
- ATPase pumps
- Why are myelinated axons more energy efficient than unmyelinated axons?
- myelinated axons have fewer ATPases (only at nodes of Ranvier), therefore they use less ATP.
- There are two types of electrical synapses: what are they and how does each type work?
- 1. Ephatic transmission (ion flow in one axon influences other axons)
2. Gap junctions (pores that connect adjacent cells)
- What are the special structures (2) for chemical neurotransmission called and where is each found?
- 1. terminal boutons (at axon terminal)
2. en passant boutons (along the axonal length)
- which is slower: chemical or electrical synapses?
- chemical synapses are slower (neurotransmitter must cross synaptic cleft and act on receptors). electrical synapses are virtually instant
- Which ion is essential for presynaptic transmission?
- Ca++ (rushes into neuron and causes vesicles to fuse w/plasma membrane)
- What happens once the neurotransmitter binds to its postsynaptic receptor?
- Ion channels open, ions flow in and alter membrane potential in postsynaptic cell. (this may initiate or inhibit an AP here)
- in a neuromuscular junction: what is the presynaptic neuron and what is the postsynaptic cell?
- presynaptic neuron: a-motor neuron
postsynaptic cell: skeletal muscle
- What neurotransmitter is used exclusively by the NMJ and is it (+) or (-)?
- ALWAYS Acetylcholine
- Where are neuron-neuron chemical synapses found? Are they (+) or (-)
- In both the CNS and PNS. May be either (+) or (-)
- What is a postsynaptic potential? Is it (+) or (-)
- a slow potential that sums temporally and spacially to sometimes form a postsynaptic AP. Can be either (+)EPSP or (-)IPSP
- EPSPs are due to the influx of what ion?
What about IPSPs?
- EPSPs: due to influx of Na+ or Ca++ (depolarize)
IPSPs: due to influx of Cl- (hyperpolarize)
- T/F: EPSPs and IPSPs can sometimes cancel eachother out.
- TRUE. When an EPSP and an IPSP occur at the same time the net effect is 0. (they cancel eachother out)
- what is presynaptic inhibition of a postsynaptic potential?
- when presynaptic axon terminals are inhibited there is no terminal depolarization: therefore no postsynaptic depolarization
- Mini end plate potentials sum up to form ___________, which are a form of postsynaptic potential.
- end plate potentials
- what is the result of a miniature end plate potential?
- results in a spontaneous release of one synaptic vesicle worth of neurotransmitter (1 quantum)
- What is the difference between secretory vesicles and synaptic vesicles?
- secretory vesicles: contain neuropeptides, open anywhere along axon
synaptic vesicles: contain neurotransmitters, open only at terminal or passant boutons.
- What is a docking complex?
- a specialization in the presynaptic membrane that binds synaptic vesicles.
- T/F: synaptic vesicles are recycled. Why/why not?
- TRUE - this cuts down on time (otherwise vesicles have to come from neuronal soma)
- What determines the number of vesicles released during one AP?
- amount of Ca++ influx into cell
- What 2 proteins prime the vesicle for fusion to the docking complex of the presynaptic membrane?
- NSF and SNAP
- SNAP and NSF regulate ___________.
- the assembly of SNAREs (SNAP receptors)
- what is the name of the protein that binds Ca++ upon its influx into the presynaptic terminal? What is it's other function?
- synaptogogmin: also senses Ca++ levels and triggers vesicle fusion
- Name the 3 protiens involved in vesicle recycling. what are their specific functions?
- 1. clathrin - buds recycled vesicles from plasma membr.
2. dynamin - pinches off membranes after budding
3. synapsin - keeps vesicles tethered to cytoskeleton for a reserve pool.
- define: neurotransmitter
- neural signalling molecules that can act alone
- what is the difference between a neurotransmitter and a neuromodulator/neuroeffector?
- neurotransmitters act alone (primary signaling molecule)
neuromodulators are secondary neurotransmitters as they modify the signal of the primary neurotransmitter
- Give an example of:
1. a neurotransmitter and
2. a neuromodulator/effector.
- 1. acetylcholine
- Give an example of:
1. a small molecule neurotransmitter
2. a neuropeptide
3. a gas neurotransmitter
- 1. classic transmitters: Ach, glutamate, aspartate, GABA, glycine, ATP, DA, NE
2. any peptide 3-26 aa long
3. NO, CO
- small neuropeptides are synthesized in ____________, whereas peptide neurotransmitters are synthesized in ___________.
- neuron terminals
- What are the 3 ways a neurotransmitter is removed from the synaptic cleft?
- 1. diffusion
2. reuptake in neuron or glia
- When would a cotransmitter be observed?
- when a neuron makes and releases more than 1 neurotransmitter
- What decides the neurotransmitter action (whether the AP is (+) or (-))?
- type and location of neurotransmitter receptors.
- what is the difference between:
1. cell-permeant (intracellular) receptors
2. cell-impermeant (transmembrane) receptors?
- 1. A lipophilic neurotransmitter crosses the p.m. to access the receptors inside.
2. neurotransmitter binds to receptors found on the membrane.
- What are 3 types of transmembrane (cell-impermeant) receptors?
2.enzyme linked - alters intracellular target proteins
3. metabotropic (G-protein coupled), initates GTP-mediated cascade.
- which receptor is faster: an ionotropic or metabotropic receptor?
- ionotropic - msec response
(vs. metabotropic, sec->min response)
- what is the advantage of a metabotropic receptor?
- these receptors can amplify signals by activating signal transduction: signal is also long lasting
- What is the basic pathway through a metabotropic receptor (binding to eventual physiological response)
- NT binds,(+) G-protein,(+) 2nd messenger, this (+) enzymes that alter the phosphorylation of protiens, which alters RNA and protein synthesis.
- give an example of 4 second messengers used by metabotropic receptors.
- 1. Ca++
2. cAMP, cGMP
3. IP3, DAG
- Regarding Ach:
1. where found?
3. Removal mechanism?
4. classes of receptors?
- 1. NMJ, glands, (+) in CNS
2. acetyl CoA & choline
4. nicotinic, muscarinic
- nicotinic receptors:
2. usually (+) or (-)
- 1. ligand-gated
2. (+) because open to all cations
- muscarinic receptors:
1. type (class)
2. two kinds of muscarinic receptors, name&where found?
- 1. metabotropic, in CNS & PNS
2. M1-CNS, M2-peripheral
3. muscarine, pilocarpine
4. atropine, scopolamine
- Neurotransmitter used by 95% of ecitatory neurons in brain?
1. where made?
3. types (classes) of receptors?
- 1. nerve terminals
2. glutamine (from glia), or glucose (via TCA cycle)
3. both ionotropic and metabotropic
- Does glutamate cross the BBB?
- NO (therefore it must be synthesized in within the CNS)
- PCP and ketamine are antagonists at which receptors? What neurotransmitter normally binds here?
- *NMDA receptors
*glutamate normally binds to NMDA receptors
- What are the two major inhibitory neurotransmitters of the CNS and, more specifically, where are they found?
- GABA (brain)
Glycine (spinal cord)
- why is strichnine toxic?
- b/c it blocks glycine receptors
- catecholamines, seratonin and histamine can all be classified as _____________.
- biologic amines
- Where is NE made in the CNS?
what is the precursor?
- in the locus ceruleus (precursor - tyrosine)
- What are the 2 enzymes that remove catecholamines?
Where are they found?
Both found in neurons & glia
- what type of receptors do catecholamines use?
- metabotropic receptors (that are G protein coupled)
- what type of receptors do histamines use?
- metabotropic (H1-H4)
- which H receptor do antihistamines and anti-nausea medications work against?
- 1. Where is seratonin made?
3. what is the name of the only ionotropic seratonin receptor?
- 1. main Raphe nucleus
- what type of receptors are 5-HT1 and 5-HT2 receptors? function?
- *metabotropic seratonin receptors
*implicated in higher functions and motor behaviors
- What is the source of ATP, AMP and adenosine in the CNS?
- comes from mitochondrial oxidative phosphorylation and glycolysis
- Purines have what type of receptors?
- both ionotropic(+) and metabotropic(-)
- how does coffee work?
- blocks adenosine metabotropic(-) receptors in the CNS; therefore stimulates
- morphine and other narcotics are _________ neurotransmitters. (class) They act at __________ receptors.
- m-opiod receptors are what type of receptor? The fact that morphine can act at such a low concentration classifies it as_________ action.
- T/F: peptides can be found & released anywhere along an axon. Release is slow
slow release, however, do not need docking complexes to coordinate exocytosis.
- What are the 5 terminal branches of CN VII?
- what three muscles make up the "nasal group?"
- 1. nasalis
3. depressor septi
- name the four deep muscles of the face
- 1. buccinator
2. levator anguli oris
3. depressor labii inferiorus
- Name the 8 superficial muscles of the face.
- orbicularis oris, zygomaticus major and minor, levator labii superioris, levator labii superioris aleque nasi, depressor anguli oris, platysma, risorius
- what muscle is found in the temporal fossa?
- Where are the branches of the anterior division of the mandibular branch of CN V going?
- motor: to temporalis, masseter, lateral and medial pterygoids
- What are the branches of the posterior division of the mandibular branch of CN V?
- motor: to mylohyoid and ant. belly of digastric
sensory: auriculotemporal n., lingual n, inferior alveolar n.
You must Login or Register to add cards