p.23
Termination of Neurotransmitter Effects
What role does Acetylcholinesterase play in neurotransmitter termination?
It breaks down Acetylcholine in the synaptic cleft.
p.22
Neurotransmitter Release and Reception
What type of neurotransmitter is glycine and what effect does it have?
Glycine is a small-molecule neurotransmitter that opens IPSP, similar to GABA.
p.11
Synaptic Integration and Neuronal Firing
How does incoming information through synapses affect neuronal activity?
The neuron decides whether to fire an action potential based on the incoming action potentials propagating along the fiber.
p.21
Neurotransmitter Release and Reception
How does the electrochemical gradient of H+ affect neurotransmitter accumulation?
The electrochemical gradient of H+ allows for the accumulation of high concentrations of neurotransmitter in the vesicle, facilitating rapid release when the vesicle fuses with the plasma membrane.
p.18
Neurotransmitter Release and Reception
What neurotransmitter do inhibitory fibers release and which receptors do they bind to?
Inhibitory fibers release GABA and bind to GABA-A receptors.
p.9
Action Potentials and Electrical Signals
What causes the depolarization and suprathreshold depolarization in nerve cells?
Open mechanosensitive channels allow Na+ sodium influx.
p.13
Types of Synapses: Electrical vs. Chemical
What forms the gap junctions between two neurons?
Connexin subunits form connexons, which interconnect the cytoplasms of the two neurons.
p.13
Types of Synapses: Electrical vs. Chemical
What happens when one cell is depolarized in an electrical synapse?
The other cell is also depolarized, allowing for synchronization.
p.19
Synaptic Integration and Neuronal Firing
What effect does a large maintained EPSP have on action potential frequency?
A large maintained EPSP results in high action potential frequency.
p.23
Termination of Neurotransmitter Effects
Is binding to receptors a major pathway for neurotransmitter elimination?
No, because the transmitter can dissociate from the postsynaptic receptor after a while.
p.7
Sensory Receptors and Signal Detection
What is the relationship between mechanical stimulus size and receptor potential in sensory receptors?
A small mechanical stimulus causes a small depolarization, while a large mechanical stimulus results in a large depolarization.
p.6
Neuronal Structure: Dendrites, Axons, and Cell Body
What type of neuron is characterized as the fastest?
A-alpha neurons are the fastest.
p.6
Neuronal Structure: Dendrites, Axons, and Cell Body
Which type of neuron is the slowest and unmyelinated?
C fibers are the slowest and unmyelinated.
p.18
Synaptic Integration and Neuronal Firing
What happens when two action potentials occur rapidly in fiber A?
Two action potentials in fiber A lead to two EPSPs, resulting in a higher amplitude due to temporal summation.
p.19
Synaptic Integration and Neuronal Firing
What is the relationship between small maintained summed EPSP and action potential frequency?
Small maintained summed EPSP results in low action potential frequency.
p.19
Neurotransmitter Release and Reception
What role do synaptic vesicles play in the context of EPSP and action potentials?
Synaptic vesicles are involved in the release of neurotransmitters that contribute to the generation of EPSPs.
p.23
Termination of Neurotransmitter Effects
How does cocaine affect neurotransmitter levels in the synaptic cleft?
Cocaine prevents the uptake of epinephrine, resulting in more epinephrine remaining in the synaptic cleft.
p.11
Types of Synapses: Electrical vs. Chemical
What types of synapses are mentioned in the text?
Axodendritic, axosomatic, and axoaxonic synapses.
p.7
Sensory Receptors and Signal Detection
What type of potential is generated in sensory receptors due to mechanical stimuli?
Receptor potential, which is an electrotonic potential.
p.22
Termination of Neurotransmitter Effects
What is the process for terminating the effects of neurotransmitters?
Termination of transmitter effects involves various mechanisms to stop neurotransmitter action.
p.7
Sensory Receptors and Signal Detection
What happens to the receptor potential when the mechanical stimulus is removed?
There is a decay in time of the receptor potential.
p.10
Action Potentials and Electrical Signals
What is the effect of a weak suprathreshold stimulus on action potential firing?
A weak suprathreshold stimulus results in low frequency action potential firing.
p.7
Sensory Receptors and Signal Detection
Why might the receptor potential not reach the CNS?
The receptor potential decays in space and does not propagate effectively to the cell body, preventing it from reaching the CNS.
p.23
Termination of Neurotransmitter Effects
What are the three main pathways for the termination of neurotransmitter effects?
Transmitter diffusion away, uptake by presynaptic terminal, and enzymatic breakdown.
p.22
Neurotransmitter Release and Reception
What are the two types of receptors for Acetylcholine?
Muscarinic and nicotinic receptors.
p.11
Action Potentials and Electrical Signals
What happens to the membrane potential when the receptor potential is larger?
The membrane potential reaches the threshold earlier, leading to a shorter time period between action potentials and a larger action potential frequency.
p.22
Neuronal Structure: Dendrites, Axons, and Cell Body
Where is glycine primarily found?
In the spinal cord and other areas.
p.3
Action Potentials and Electrical Signals
What is the nature of action potentials in neurons?
Action potentials are an all-or-none response that either fully develops or does not occur at all.
p.3
Action Potentials and Electrical Signals
What is the amplitude range of an action potential?
The amplitude of an action potential is several times 10mV, typically reaching +20 or +30mV.
p.18
Synaptic Integration and Neuronal Firing
What is the effect of a single excitatory fiber stimulation on typical CNS neurons?
Stimulation of a single excitatory fiber is not enough to evoke an action potential in typical CNS neurons.
p.9
Action Potentials and Electrical Signals
What happens when voltage-gated sodium channels open?
An action potential is generated.
p.7
Sensory Receptors and Signal Detection
How does distance from the channel affect the amplitude of the signal in sensory receptors?
The voltage meter far from the channel shows a lesser amplitude signal, indicating decay in space.
p.9
Action Potentials and Electrical Signals
What occurs due to large depolarization in the action potential process?
Voltage-gated K+ potassium channels open while voltage-gated sodium channels inactivate.
p.13
Neurotransmitter Release and Reception
What is the role of synaptic vesicles in chemical synapses?
They contain neurotransmitter molecules and are involved in neurotransmitter release.
p.7
Action Potentials and Electrical Signals
What must occur for the receptor potential to evoke an action potential?
The receptor potential must be sufficient to reach the threshold needed to generate an action potential.
p.5
Action Potentials and Electrical Signals
What is the characteristic of action potentials in terms of direction?
Action potentials are unidirectional, meaning they travel in one direction only.
p.12
Types of Synapses: Electrical vs. Chemical
What are the two main types of synapses?
Electrical and Chemical synapses.
p.20
Axonal Transport and Synaptic Vesicle Dynamics
What are the constituents of a synaptic vesicle?
Neurotransmitters and proteins involved in exocytosis.
p.2
Neuronal Structure: Dendrites, Axons, and Cell Body
What structures are contained within the cell body of a neuron?
The cell body contains the nucleus, endoplasmic reticulum (ER), Golgi apparatus, and is responsible for synthesizing most proteins of the neuron.
p.16
Synaptic Integration and Neuronal Firing
What role does magnesium play in NMDA receptors?
Magnesium binds to the NMDA receptor's pore; depolarization expels the Mg plug, allowing current to flow.
p.4
Myelination and Action Potentials
How does the myelin sheath affect action potential propagation?
The myelin sheath acts as an electrical insulator, resulting in very rapid propagation of action potentials and increasing the velocity of propagation.
p.2
Neuronal Structure: Dendrites, Axons, and Cell Body
What occurs at the axon terminals of a neuron?
Axon terminals form synapses where outgoing signals pass to the dendrites of other neurons.
p.16
Synaptic Integration and Neuronal Firing
What causes an IPSP?
An IPSP is caused by the opening of ligand-gated chloride channels and sometimes potassium channels, leading to small hyperpolarization.
p.2
Action Potentials and Electrical Signals
What are the two categories of electrical signals in neurons?
The two categories of electrical signals are electrotonic potentials and action potentials.
p.8
Sensory Receptors and Signal Detection
What causes electrotonic depolarization?
Electrotonic depolarization is caused by the opening of mechanosensitive channels.
p.2
Action Potentials and Electrical Signals
What are the properties of electrotonic potentials?
Electrotonic potentials are graded, have low amplitude (about 1/10 mV), are localized, decay in space, and decay in time if no current flows.
p.15
Neuronal Structure: Dendrites, Axons, and Cell Body
What functions do mitochondria serve in the axon terminal?
Mitochondria pump out calcium, operate the Na+/K+ pump, and fill synaptic vesicles with neurotransmitter, all requiring ATP.
p.8
Sensory Receptors and Signal Detection
What happens with a subthreshold mechanical stimulus?
It results in a small receptor potential that decays without generating an action potential, so the signal does not travel to the center.
p.17
Synaptic Transmission Mechanisms
What do excitatory fibers release and what do they bind to?
Excitatory fibers release glutamate, which binds to AMPA receptors.
p.11
Action Potentials and Electrical Signals
What determines the frequency of action potential series?
The frequency depends on the amplitude of electrotonic depolarization.
p.21
Neurotransmitter Release and Reception
What is the role of the V-type proton pump in neurotransmitter storage?
The V-type proton pump uses ATP to pump protons into the lumen of the vesicle, acidifying it and creating a high concentration of H+, which drives the uptake of neurotransmitters as a secondary active transport process.
p.22
Neurotransmitter Release and Reception
What is the role of catecholamines in neurotransmission?
Catecholamines interact with noradrenergic receptors.
p.21
Neurotransmitter Release and Reception
What are the criteria for a substance to be classified as a neurotransmitter?
1. It should be present in the presynaptic nerve terminal and synthesized by the presynaptic neuron. 2. Presynaptic depolarization should lead to its release. 3. There should be a specific receptor on the postsynaptic cell. 4. Binding should evoke an effect on the postsynaptic neuron, such as EPSP or IPSP.
p.11
Neuronal Structure: Dendrites, Axons, and Cell Body
What are dendritic spines?
Small compartments found on some dendrites that form axospinous synapses.
p.21
Synaptic Transmission Mechanisms
What happens when a neurotransmitter binds to its receptor on the postsynaptic neuron?
The binding of the neurotransmitter should evoke an effect on the postsynaptic neuron, resulting in either an excitatory postsynaptic potential (EPSP) or an inhibitory postsynaptic potential (IPSP).
p.5
Action Potentials and Electrical Signals
How does the conduction speed of myelinated axons compare to unmyelinated axons?
Myelinated axons conduct faster due to saltatory conduction.
p.6
Neuronal Structure: Dendrites, Axons, and Cell Body
Where is the cell body of primary sensory neurons located?
The cell body is located in the dorsal root ganglion or trigeminal ganglion.
p.18
Synaptic Integration and Neuronal Firing
What is spatial summation in the context of action potentials?
Spatial summation occurs when action potentials at fibers A and B combine to produce a larger depolarizing effect than stimulation of one alone.
p.6
Sensory Receptors and Signal Detection
What type of neuron is described as mechano-sensitive?
The peripheral axon of primary sensory neurons that runs to the skin is mechano-sensitive.
p.9
Action Potentials and Electrical Signals
What effect does the opening of voltage-gated K+ potassium channels have on the membrane potential?
It hyperpolarizes the membrane potential below the threshold line.
p.13
Neurotransmitter Release and Reception
What is the function of docking proteins in the active zone of a chemical synapse?
They facilitate the fusion of the synaptic vesicle to the plasma membrane upon receiving a calcium signal.
p.14
Axonal Transport and Synaptic Vesicle Dynamics
What happens to the vesicle membrane after neurotransmitter release?
The vesicle membrane may become part of the plasma membrane, or it may undergo a 'Kiss & Run' mechanism where it releases neurotransmitter and then closes again to be refilled.
p.14
Synaptic Transmission Mechanisms
What type of channel opens when neurotransmitter binds to the postsynaptic receptor?
A ligand-gated cation channel.
p.5
Action Potentials and Electrical Signals
What is the significance of electrotonic potential in action potential propagation?
Electrotonic potential spreads rapidly between nodes, allowing the action potential to reach threshold at the next node.
p.14
Synaptic Integration and Neuronal Firing
What is the result of sodium influx through the cation channel in the postsynaptic cell?
It causes a small depolarization known as excitatory postsynaptic potential (EPSP).
p.14
Synaptic Integration and Neuronal Firing
What occurs when a chloride channel opens in response to neurotransmitter binding?
Chloride ions move into the cell, causing hyperpolarization, which is known as inhibitory postsynaptic potential (IPSP).
p.20
Axonal Transport and Synaptic Vesicle Dynamics
What role do transmembrane proteins play in synaptic vesicles?
They facilitate the association of the vesicle with the active cytoskeleton for exocytosis.
p.14
Neurotransmitter Release and Reception
What type of receptor can also be activated by neurotransmitters besides ligand-gated channels?
G-protein coupled receptors.
p.20
Axonal Transport and Synaptic Vesicle Dynamics
What is the function of the neurotransmitter-proton exchanger protein?
It is responsible for the uptake of neurotransmitters into the synaptic vesicle.
p.12
Types of Synapses: Electrical vs. Chemical
How does neurotransmitter release occur in chemical synapses?
Neurotransmitters are released from the axon terminal and evoke effects on the postsynaptic membrane.
p.8
Sensory Receptors and Signal Detection
What happens to receptor potential during depolarization?
The receptor potential spreads with decrement.
p.8
Action Potentials and Electrical Signals
Where does the depolarization arrive with the highest density of voltage-gated sodium channels?
It arrives at the region around the first myelin sheath.
p.20
Axonal Transport and Synaptic Vesicle Dynamics
What is the process by which neurotransmitters are transported from the cell body to the axon terminal?
Axonal transport, specifically anterograde transport.
p.5
Action Potentials and Electrical Signals
What ensures that action potentials are loss-free?
Producing an action potential at one end will always reach the other end without being lost.
p.3
Action Potentials and Electrical Signals
How does an action potential propagate along a neuron?
An action potential propagates by regenerating at different regions of the cell, with voltage-gated sodium channels activating and causing a large sodium influx.
p.18
Synaptic Integration and Neuronal Firing
What is the result of stimulating both excitatory fiber A and inhibitory fiber C?
Stimulating both A (excitatory) and C (inhibitory) results in EPSP and IPSP that can cancel each other out.
p.6
Action Potentials and Electrical Signals
What happens to the mechanosensitive ion channel under resting conditions?
Under resting conditions, the mechanosensitive ion channel is closed.
p.20
Axonal Transport and Synaptic Vesicle Dynamics
What is retrograde transport?
The transport of materials from the axon terminal back to the cell body.
p.10
Neuronal Structure: Dendrites, Axons, and Cell Body
What is the role of voltage-gated potassium channels during action potentials?
Voltage-gated potassium channels open during depolarization, causing an outward flow of K+ ions, which hyperpolarizes the membrane potential.
p.4
Neuronal Structure: Dendrites, Axons, and Cell Body
How does the electrical resistance of thick fibers compare to that of thin fibers?
Thick fibers have much less electrical resistance in their interior, allowing a higher percentage of current to enter the axis of the axon and a smaller percentage to leave.
p.9
Action Potentials and Electrical Signals
What maintains sodium influx during the action potential cycle?
Mechanosensitive channels allow continued sodium influx.
p.2
Neuronal Structure: Dendrites, Axons, and Cell Body
What is the primary function of the cell body in a neuron?
The cell body is considered the metabolic control center, acting as a manufacturing and recycling plant for the neuron.
p.1
Types of Synapses: Electrical vs. Chemical
What types of synapses exist between neurons?
Types of synapses include axodendritic synapses, where an axon terminal connects to a dendrite, and axosomatic synapses, where an axon terminal connects to the cell body of another neuron.
p.12
Types of Synapses: Electrical vs. Chemical
What characterizes an electrical synapse?
It has gap junctions between neighboring neurons, allowing current to flow bidirectionally with no delays.
p.20
Axonal Transport and Synaptic Vesicle Dynamics
How are neurotransmitters filled into vesicles?
They are filled into vesicles at the axon terminal, with the vesicle membrane produced in the cell body.
p.1
Synaptic Transmission Mechanisms
What is the role of axon terminals in neuronal communication?
Axon terminals are important for the formation of synapses, allowing connections between neurons.
p.4
Myelination and Action Potentials
What is the major determinant of the velocity of action potential propagation?
The major determinant of the velocity of propagation is the myelination of the axon.
p.2
Neuronal Structure: Dendrites, Axons, and Cell Body
How many axons does a typical neuron have?
Typically, a neuron has one axon responsible for transmitting outgoing signals to axon terminals.
p.17
Neurotransmitter Release and Reception
What is the frequent inhibitory neurotransmitter mentioned?
GABA (gamma amino-butyric acid)
p.15
Action Potentials and Electrical Signals
What happens when an action potential arrives at the axon terminal?
Depolarization occurs, leading to the opening of N/P type calcium channels.
p.17
Synaptic Integration and Neuronal Firing
What is the effect of the beta/gamma subunit of the Gi protein?
It activates the opening of K+ channels, leading to a rapid outflow of potassium and resulting in hyperpolarization (IPSP).
p.17
Neurotransmitter Release and Reception
What are benzodiazepines and barbiturates known for in relation to GABA?
They are activators of GABA A receptors, acting as tranquilizers that induce sleepiness and relaxation.
p.8
Action Potentials and Electrical Signals
What happens if a mechanical stimulus is maintained?
There can be many successive action potentials generated one after another.
p.10
Action Potentials and Electrical Signals
How does a strong stimulus affect action potential frequency?
A strong stimulus leads to high frequency action potential firing, with the neuron capable of producing up to 500 action potentials per second.
p.1
Sensory Receptors and Signal Detection
What are sensory receptors and their role in the detection of stimuli?
Sensory receptors are specialized nerve endings that detect different stimuli and provide electrical signals sent into the CNS.
p.10
Action Potentials and Electrical Signals
How is stimulus intensity encoded in action potentials?
Stimulus intensity is encoded in action potential frequency, where a weak stimulus evokes low frequency and a strong stimulus evokes high frequency.
p.4
Axonal Transport and Synaptic Vesicle Dynamics
What is the effect of axoplasm on current flow in the cytoplasm of the axon?
Axoplasm has high resistance, leading to a major percentage of current leaving and less current entering the cytoplasm of the axon.
p.3
Action Potentials and Electrical Signals
What is electrotonic depolarization?
Electrotonic depolarization occurs when a large sodium current in one region of the membrane causes depolarization in the adjacent region, activating sodium channels there.
p.13
Types of Synapses: Electrical vs. Chemical
What is the size of the synaptic cleft in chemical synapses compared to electrical synapses?
~20-50 nm, which is larger than that of electrical synapses.
p.16
Neurotransmitter Release and Reception
What are the types of glutamate receptors on the postsynaptic membrane?
The types of glutamate receptors are ionotropic receptors (like AMPA and NMDA) and metabotropic receptors (G-protein coupled receptors).
p.3
Action Potentials and Electrical Signals
How does the diameter of an axon affect the velocity of action potential propagation?
Thicker fibers have a larger velocity of propagation than thinner fibers because the current entering through voltage-gated sodium channels spreads less in thinner axons due to rapid leakage through the plasma membrane.
p.5
Action Potentials and Electrical Signals
Why can action potentials not reverse direction?
Because the region of origin has inactive voltage-gated sodium channels and activated potassium channels.
p.16
Synaptic Transmission Mechanisms
What is the function of AMPA receptors?
AMPA receptors are permeable to 'one-charge' cations, primarily allowing sodium influx into the cell.
p.9
Action Potentials and Electrical Signals
What occurs when the mechanical stimulus is finished?
No further depolarization occurs.
p.16
Synaptic Transmission Mechanisms
How do NMDA receptors operate?
NMDA receptors are permeable to sodium and calcium, requiring both glutamate binding and depolarization to open.
p.2
Neuronal Structure: Dendrites, Axons, and Cell Body
What is the role of dendrites in a neuron?
Dendrites receive incoming signals from other neurons and typically have several branches.
p.12
Types of Synapses: Electrical vs. Chemical
Where are electrical synapses commonly found?
In smooth muscle and heart muscle.
p.12
Types of Synapses: Electrical vs. Chemical
What is the mechanism of transmission in electrical synapses?
Electric conduction through gap junctions.
p.4
Neuronal Structure: Dendrites, Axons, and Cell Body
What happens to current in the region of the myelin sheath?
In the region of the myelin sheath, current cannot leave the axon and must travel inside the axon, leading to a very large space constant.
p.17
Synaptic Transmission Mechanisms
What happens when GABA binds to the GABA A receptor?
The GABA-A channel opens, allowing chloride to flow into the postsynaptic cell, resulting in hyperpolarization and an inhibitory postsynaptic potential (IPSP).
p.12
Types of Synapses: Electrical vs. Chemical
What is contained in the presynaptic part of a chemical synapse?
Synaptic vesicles containing neurotransmitter molecules.
p.12
Types of Synapses: Electrical vs. Chemical
What happens to the vesicle in a chemical synapse?
The vesicle fuses to the plasma membrane and releases neurotransmitters.
p.12
Types of Synapses: Electrical vs. Chemical
Are there any exceptions to the unidirectional flow in chemical synapses?
Yes, there are some special cases of retrograde transmission.
p.15
Axonal Transport and Synaptic Vesicle Dynamics
What characterizes electrodens vesicles?
They contain peptide transmitters, are not in a docked position, and are released when the axon terminal is stimulated repeatedly.
p.8
Action Potentials and Electrical Signals
What occurs with a suprathreshold stimulus?
It causes electrotonic depolarization that reaches the threshold of voltage-gated sodium channels, resulting in an action potential.
p.14
Neurotransmitter Release and Reception
What triggers the release of neurotransmitters at the axon terminal?
The influx of calcium ions through voltage-gated calcium channels after an action potential arrives at the axon terminal.
p.5
Action Potentials and Electrical Signals
What does it mean for action potentials to be error-free?
If no action potential is made, it will not arrive at the other end.
p.1
Action Potentials and Electrical Signals
What is the function of action potentials in the nervous system?
Action potentials propagate electrical signals rapidly along nerve fibers to the CNS for processing.
p.18
Synaptic Integration and Neuronal Firing
What is required for the postsynaptic cell to fire?
The final outcome of summed postsynaptic potentials must reach depolarization threshold for the postsynaptic cell to fire.
p.9
Action Potentials and Electrical Signals
What happens to inactive sodium channels after depolarization?
They can return to a closed state.
p.6
Action Potentials and Electrical Signals
What occurs when the mechanosensitive ion channel opens?
When the channel opens, mostly sodium flows into the nerve ending, causing a small depolarization.
p.1
Neuronal Structure: Dendrites, Axons, and Cell Body
What are the basic regions of an idealized neuron?
An idealized neuron has four basic regions: cell body (soma), dendrites, axon, and axon terminals.
p.10
Action Potentials and Electrical Signals
What is the depolarizing effect caused by receptor potential?
The depolarizing effect is due to a maintained mechanical stimulus that causes Na+ influx through open mechanosensitive channels.
p.4
Action Potentials and Electrical Signals
What is the relationship between fiber thickness and electrotonic potential decay?
In thick fibers, the electrotonic potential decays less in space due to a larger space constant.
p.10
Neuronal Structure: Dendrites, Axons, and Cell Body
What happens to voltage-gated potassium channels after a mechanical stimulus?
Voltage-gated potassium channels gradually close after some time since there is no depolarization to trigger them.
p.4
Action Potentials and Electrical Signals
What role do voltage-gated sodium channels play in thick fibers?
Voltage-gated sodium channels in thick fibers allow for a larger range, resulting in a higher velocity of propagation for action potentials.
p.9
Action Potentials and Electrical Signals
What happens to the membrane potential after the activation of voltage-gated K+ potassium channels?
The membrane potential will return to resting level in the absence of depolarizing current.
p.16
Synaptic Integration and Neuronal Firing
What is the effect of metabotropic receptors?
Metabotropic receptors cause small hyperpolarizations (IPSP) of 0.1-5 mV for milliseconds, stabilizing the membrane potential at negative values.
p.14
Synaptic Transmission Mechanisms
What is the role of the heterotrimeric G-protein in the postsynaptic cell?
It activates signaling pathways that can change the activity of ion channels, leading to either depolarization or hyperpolarization.
p.12
Types of Synapses: Electrical vs. Chemical
What is the direction of flow in chemical synapses?
Unidirectional flow from presynaptic to postsynaptic.
p.17
Neurotransmitter Release and Reception
What type of receptor is GABA B and what protein is it coupled to?
GABA B is a 7 TM receptor coupled to Gi protein.
p.15
Neurotransmitter Release and Reception
What is the role of calcium in neurotransmitter release?
Calcium enters the axon terminal, triggering exocytosis and the release of neurotransmitter.
p.15
Synaptic Transmission Mechanisms
How does a neurotransmitter affect the postsynaptic cell?
It binds to postsynaptic receptors, which can lead to excitatory postsynaptic potential (EPSP) or inhibitory effects depending on the ligand-gated channel type.
p.17
Neuronal Structure: Dendrites, Axons, and Cell Body
Where is the membrane potential measured in a neuron?
At the axon hillock, which is the initial segment of the axon.
p.17
Action Potentials and Electrical Signals
What is typically produced at the axon hillock?
An action potential, due to the highest number of voltage-gated sodium channels present there.
p.15
Synaptic Integration and Neuronal Firing
What is the nature of EPSP?
EPSP is a small depolarization lasting for milliseconds, typically caused by the opening of ligand-gated non-selective cation channels.
p.8
Action Potentials and Electrical Signals
What occurs if depolarization reaches the threshold of voltage-gated sodium channels?
The channel opens, leading to the generation of an action potential.
p.8
Neurotransmitter Release and Reception
What effect does lidocaine have on action potential generation?
Lidocaine blocks voltage-gated sodium channels, preventing action potential generation and resulting in no pain sensation.
p.17
Types of Synapses: Electrical vs. Chemical
What type of synapse do C fibers form?
C fibers form axo-somatic synapses and are inhibitory.
p.15
Neurotransmitter Release and Reception
What neurotransmitter is frequently associated with EPSP?
Glutamate, which is packed into synaptic vesicles and released into the synaptic cleft.
