Nerve physiology Flashcards
Unidirectional transmission of impulse
ORTHODROMIC TRANSMISSION
Stimulation of an axon will transmit impulse away from the cell body
Anterograde
Stimulation of a dendrite will transmit impulse towards the cell body
Retrograd
ANTIDROMIC TRANSMISSION
Stimulation of the central portion of the axon will result a bidirectional transmission of impulses; towards the cell body and away from the cell body
13. Which type of nerve fibers innervate the polymodal nociceptors? A. Aα B. Aβ C. Aδ D. C fibers
D
14. Stimulation of which of the following fibers give rise to a longer-lasting, burning and pricking pain? A. Aα B. Aβ C. Aδ D. C fibers
D
- Which of the following mechanisms explain why visceral pain tends to be vague and poorly localized than (somatic?) pain?
A. There are more C fibers in visceral afferents than Aδ.
B. There is less overlapping of receptive fields in the viscera.
C. There are more visceral afferents that cover a wide area.
D. Visceral afferents demonstrate more converging synaptic pattern than somatic afferents
A
- the ff are characteristics of the C fibers except
a. small myelinated
b. conduction velocity ranges from .5 to 2 m/sec
c. conducts dull burning poorly localized pain
d. conducts temperature
e. no exception
A
- Vibration and position sense is conducted by ______ nerve fibers
a. a-alpha
b. a-beta
c. a-gamma
d. a-delta
e. a and b
E
- the following is true of the myelin sheath
a. it is deposited around the axon by Schwann cells
b. it is an excellent insulator for the nerve
c. it facilitates salutatory conduction
d. it increases the velocity of the nerve transmission
e. all of the above
E
Myelin production in
____ for Peripheral nervous system (SR)
___ for Central nerve system (OC
Schwann Cells
oligodendrocytes
An action potential arriving at the presynaptic terminal causes…
A) voltage-gated sodium ion channels to open, and sodium ions to diffuse into the cell.
B) voltage-gated sodium ion channels to open, and sodium ions to diffuse out of the cell.
C) voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell.
D) acetylcholine to diffuse into the cell.
E) ligand-gated sodium channels to open, and sodium ions to diffuse out of the cell.
C
As a result of question number one…
A) synaptic vessels migrate to the plasma membrane and release acetylcholine.
B) acetylcholine is actively transported from the pre-synaptic neuron.
C) acetylcholine is actively transported to the post synaptic neuron.
D) ligand-gated sodium channels open.
E) sodium ions diffuse into the cell.
A
Acetylcholine has which effect on the post-synaptic neuron?
A) Ligand gated calcium ion channels open and calcium diffuses in.
B) Ligand gated sodium ion channels open and sodium diffuses in.
C) Terminal vessels migrate to the plasma membrane.
D) Voltage gated calcium ion channels open and calcium diffuses in.
E) Voltage gated sodium ion channels open and sodium diffuses in.
B
If the post-synaptic membrane potential reaches threshold level, an action potential will be produced.
A) True
B) False
A
Acetylcholine is actively transported from the pre-synaptic membrane to the post-synaptic membrane.
A) True
B) False
B
—: membrane protein attached on the membrane of the vesicle
Vesicle associated membrane protein
—- :
attached to the membrane of the presynaptic cell
– and –:
enhance binding of the synaptobrevin and syntaxin
Synaptobrevin
Syntaxin
SNAP 25 and Rab 3
moa of botulinum infection?
destroy snare proteins; exocytosis of NTs cannot occur
Graded potentials:
__:
Depolarizes membrane potential
___:
Hyperpolarizes membrane potential
Excitatory (produces EPSP)
Inhibitory (produces IPSP)
—-are changes in membranepotentialthat vary in size, as opposed to being all-or-none.
They arise from the summation of the individual actions of ligand-gated ion channel proteins, and decrease over time and space. They do not typically involve voltage-gated sodium and potassium channels.
Graded potentials
Most often evoked by GABA or glycine-ergic presynaptic neurons
Neurotransmitter binding opens Cl- channels
IPSP
Most often evoked by glutaminergic (CNS) and cholinergic (PNS) presynaptic neurons
Neurotransmitter binding opens cation channels (permeable to Na+, Ca2+, K+)
EPSP
Most often evoked by glutaminergic (CNS) and cholinergic (PNS) presynaptic neurons
Neurotransmitter binding opens cation channels (permeable to Na+, Ca2+, K+)
D.
Summation does not occur in action potentials because action potentials have constant amplitude and form and it is an all-or-none response
T/F: GABA as a neurotransmitter is both excitatory and inhibitory
F, it is strictly inhibitory
summation of simultaneous inputs at different sites
Spatial Summation
summation of consecutive inputs at same site
Temporal Summation
Which of the following is/are features of voltage-gated sodium channel/s?
They are open when the membrane is hyperpolarized
They have high conductance in the resting state
They are closed when the cell is at rest
They pump 3 sodium out
of the cell and 2 potassium ions inwards
C
The final physiologic action of a neurotransmitter is determined by the ____________
mechanism of termination of the physiologic effects of the neurotransmitter.
intrinsic properties of the receptor that binds with the transmitter.
intracellular 2nd messenger cascade system
chemical properties of the neurotransmitter.
B
What is the most important physiologic advantage of a chemical synapse have over an electrical synapse?
Chemical synapse can amplify signal and ensure efficient signal transmission.
It ensures unidirectional transmission of the action potential.
It has a longer lasting effect in the nervous system
It can mediate both excitatory and inhibitory responses.
A
The simplicity of electrical synapses results in synapses that are fast, but can only produce simple behaviors compared to the more complex chemical synapses.[2]
In another experimental set-up consisting of several interconnecting neurons, one neuronal circuit was found to be hyperexcitable. Electrical stimulation of the neuron that belonged to this circuit showed short latency and produced prolonged depolarization. If you want to diminish or inhibit the excitability of this neuronal circuit, what type of chemical substance or drug will you apply to the system?
one that inhibits the voltage-gated calcium channels
one that blocks sodium channels
one that increases the potassium conductance
Any of the above
D
