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Questions and Answers

Which part of the central nervous system primarily handles reflexes and independent movements?

  • Spinal Cord (correct)
  • Cerebral Cortex
  • Higher Brain
  • Lower Brain

Inhibitory signals can enhance the transmission of nerve signals.

False (B)

What plays a key role in the integration of new sensory experiences with existing memories?

Stored memories

The ___ is responsible for filtering and prioritizing new information based on memory.

<p>brain</p> Signup and view all the answers

Match the following neurotransmitter receptor types with their functions:

<p>Ionotropic receptors = Directly gate ion channels Metabotropic receptors = Act through second-messengers G-protein coupled receptors = Triggered by neurotransmitter binding Cation channels = Permit sodium influx and are excitatory</p> Signup and view all the answers

Synaptic facilitation refers to the ability of synapses to:

<p>Strengthen after repeated signals (B)</p> Signup and view all the answers

Electrical synapses allow signals to move in only one direction.

<p>False (B)</p> Signup and view all the answers

What is the primary function of presynaptic terminals?

<p>To release neurotransmitters into the synaptic cleft</p> Signup and view all the answers

The ___ is the part of the neuron that extends to communicate with other neurons.

<p>axon</p> Signup and view all the answers

Which is not a characteristic of chemical synapses?

<p>Bidirectional transmission (B)</p> Signup and view all the answers

Which of the following is a mechanism of inhibition?

<p>Opening Chloride Channels (D)</p> Signup and view all the answers

Neuropeptides are synthesized in the presynaptic terminal by ribosomes.

<p>False (B)</p> Signup and view all the answers

What is the resting membrane potential of a neuron?

<p>-65mV</p> Signup and view all the answers

During an EPSP, the influx of Na+ increases the membrane potential to __________.

<p>-45mV</p> Signup and view all the answers

Match the types of synaptic transmission with their characteristics:

<p>EPSP = Causes depolarization of the postsynaptic membrane IPSP = Causes hyperpolarization of the postsynaptic membrane Presynaptic Inhibition = Reduces excitatory effects before reaching the synapse Co-transmission = Release of multiple neurotransmitters simultaneously</p> Signup and view all the answers

What can lead to synaptic fatigue?

<p>Repetitive stimulation of excitatory synapses (C)</p> Signup and view all the answers

The time taken for neurotransmitter release and receptor binding is known as synaptic delay.

<p>True (A)</p> Signup and view all the answers

What is the role of the Na-K-ATPase pump in neuronal function?

<p>Maintains ion concentrations</p> Signup and view all the answers

During IPSP, the membrane potential can reach close to __________.

<p>-70mV</p> Signup and view all the answers

Which of the following neurotransmitters has both excitatory and inhibitory effects?

<p>Acetylcholine (A)</p> Signup and view all the answers

Which neurotransmitter is secreted mainly at synapses in the spinal cord and is always inhibitory?

<p>Glycine (C)</p> Signup and view all the answers

Dopamine is predominantly excitatory in its effects.

<p>False (B)</p> Signup and view all the answers

What area of the brain contains noradrenergic neurons that increase wakefulness?

<p>locus ceruleus</p> Signup and view all the answers

________ is secreted by the presynaptic terminals in many sensory pathways and is always excitatory.

<p>Glutamate</p> Signup and view all the answers

What is the primary role of serotonin in the nervous system?

<p>Inhibition of pain pathways (A)</p> Signup and view all the answers

Match the following neurotransmitters to their primary effect:

<p>Norepinephrine = Excitatory and inhibitory Dopamine = Usually inhibitory GABA = Primarily inhibitory in adults Glutamate = Always excitatory</p> Signup and view all the answers

Nitric oxide can alter membrane potential.

<p>False (B)</p> Signup and view all the answers

Which neurotransmitter is synthesized instantly as needed and diffuses out of the presynaptic terminals?

<p>Nitric oxide</p> Signup and view all the answers

__________ is secreted by neurons in the basal ganglia and affects the striatal region.

<p>Dopamine</p> Signup and view all the answers

Which neurotransmitter is known to have an excitatory effect during the embryonic period?

<p>GABA (A)</p> Signup and view all the answers

Which area of the nervous system is primarily responsible for coordinating fine motor control?

<p>Cerebellum (C)</p> Signup and view all the answers

Sensory information is always discarded by the brain after initial processing.

<p>False (B)</p> Signup and view all the answers

What is the primary function of synapses in the nervous system?

<p>Signal transfer between neurons</p> Signup and view all the answers

The part of the brain that acts as a relay station for sensory information is the ______.

<p>thalamus</p> Signup and view all the answers

Match the nervous system areas with their respective functions:

<p>Spinal Cord = Manages reflexive responses Cerebellum = Refines coordination and balance Basal Ganglia = Facilitates smooth voluntary movements Motor Cortex = Plans complex voluntary movements</p> Signup and view all the answers

Which structure is responsible for the contraction of smooth muscles in internal organs?

<p>Effector Receptor (D)</p> Signup and view all the answers

The axon of a neuron can receive input signals.

<p>False (B)</p> Signup and view all the answers

What is the primary role of sensory receptors in the nervous system?

<p>To detect sensory experiences and initiate nervous system activities</p> Signup and view all the answers

Signal normally passes only in the ______ direction across synapses.

<p>forward</p> Signup and view all the answers

Which structure is NOT involved in the initial processing of sensory information?

<p>Motor Cortex (B)</p> Signup and view all the answers

What occurs in synaptic facilitation?

<p>Repeated signal transmission strengthens synapses. (B)</p> Signup and view all the answers

Which type of synapse allows bidirectional transmission of signals?

<p>Electrical synapses (C)</p> Signup and view all the answers

What is primarily responsible for the inhibition of postsynaptic neurons?

<p>Increased potassium conductance (C)</p> Signup and view all the answers

What role do second-messengers play in neuronal function?

<p>They sustain prolonged neuronal excitation or inhibition. (C)</p> Signup and view all the answers

What is the primary function of the presynaptic terminal in a neuron?

<p>To release neurotransmitters into the synaptic cleft. (B)</p> Signup and view all the answers

Which anatomical structure in the CNS is primarily involved in autonomic functions?

<p>Lower brain/subcortical level (D)</p> Signup and view all the answers

What mechanism can enhance synaptic transmission?

<p>Facilitatory signals from other neurons. (A)</p> Signup and view all the answers

Which neurotransmitter is predominantly secreted by postganglionic neurons of the sympathetic nervous system?

<p>Norepinephrine (C)</p> Signup and view all the answers

What characterizes ionotropic receptors?

<p>Directly open ion channels (D)</p> Signup and view all the answers

What is a key function of the G-protein complex in signal transduction?

<p>To activate cAMP or cGMP for cellular changes. (A)</p> Signup and view all the answers

What is primarily stored in the cerebral cortex?

<p>Sensory information. (D)</p> Signup and view all the answers

What is the primary effect of glutamate when secreted in sensory pathways?

<p>Excitation of neurons (B)</p> Signup and view all the answers

Which neurotransmitter affects mood and helps in pain inhibition in the higher regions of the nervous system?

<p>Serotonin (A)</p> Signup and view all the answers

Which neurotransmitter is synthesized instantly as needed and plays a role in long-term behavior and memory?

<p>Nitric oxide (B)</p> Signup and view all the answers

During which life stage is GABA primarily excitatory rather than inhibitory?

<p>In the embryonic period (B)</p> Signup and view all the answers

What role does dopamine primarily serve in the nervous system?

<p>Inhibition (A)</p> Signup and view all the answers

Which neurotransmitter is secreted by neurons originating in the substantia nigra and primarily inhibits activity in the basal ganglia?

<p>Dopamine (C)</p> Signup and view all the answers

Where is norepinephrine primarily secreted from in the nervous system?

<p>Brainstem and hypothalamus (A)</p> Signup and view all the answers

What is the effect of glycine when secreted at synapses?

<p>Inhibitory only (C)</p> Signup and view all the answers

What is a primary effect of presynaptic inhibition at presynaptic terminals?

<p>Decreases sodium ion influx (A)</p> Signup and view all the answers

What mechanism primarily contributes to the inhibitory postsynaptic potential (IPSP)?

<p>Increased conductance of chloride ions (C)</p> Signup and view all the answers

What is primarily responsible for the coordination of fine motor control?

<p>Cerebellum (D)</p> Signup and view all the answers

Which of the following statements about small-molecule neurotransmitters is correct?

<p>They can elicit acute responses (A)</p> Signup and view all the answers

What is the effect of synaptic fatigue on neuronal firing?

<p>Decreases neurotransmitter concentration (A)</p> Signup and view all the answers

Which structure serves as a relay station for sensory information within the brain?

<p>Thalamus (B)</p> Signup and view all the answers

During which phase does spatial summation occur?

<p>When multiple presynaptic terminals fire simultaneously (C)</p> Signup and view all the answers

What is the role of synapses in neuronal communication?

<p>Serve as a junction for signal transfer (D)</p> Signup and view all the answers

Sensory information can lead to which of the following outcomes?

<p>Storage as memories for future reactions (B)</p> Signup and view all the answers

What occurs during the process of electrotonic conduction in dendrites?

<p>Direct spread of electrical currents without action potentials (D)</p> Signup and view all the answers

Which part of the nervous system is primarily for integrating sensory information for perception?

<p>Cerebral Cortex (C)</p> Signup and view all the answers

What is effect of alkalosis on neuronal excitability?

<p>It increases excitability and may trigger seizures (B)</p> Signup and view all the answers

Which characteristic of dendrites affects the efficacy of synaptic signals?

<p>Spatial field for signal summation (A)</p> Signup and view all the answers

What is the function of the reticular substance in the brain?

<p>Regulates involuntary motor functions and arousal (D)</p> Signup and view all the answers

Which neurotransmitter can have both excitatory and inhibitory effects?

<p>Acetylcholine (A)</p> Signup and view all the answers

Which is NOT a function of the motor cortex?

<p>Handles reflexive responses (D)</p> Signup and view all the answers

Which of the following describes the anatomical structures that perform functions dictated by nerve signals?

<p>Motor effectors (A)</p> Signup and view all the answers

What happens to more than 99% of sensory information in the brain?

<p>It is discarded as irrelevant (A)</p> Signup and view all the answers

Flashcards

Neuron

A specialized cell that transmits nerve impulses.

Synapse

Junction between two neurons where signals are transferred.

Sensory Receptors

Specialized cells that detect and respond to stimuli.

Sensory Information Pathway

The route sensory info takes from receptors to the brain.

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Spinal Cord (Sensory)

Initial processing of sensory information and reflexes.

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Reticular Substance

Brain area involved in arousal and involuntary motor functions.

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Cerebellum

Coordinates fine motor control and balance.

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Thalamus

Sensory relay station in the brain.

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Motor Functions

Actions like muscle contractions and gland secretions.

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Levels of Skeletal Muscle Control

Different brain areas control and refine muscle actions.

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Synaptic Facilitation

Repeated signal transmission strengthens synapses, making them better at transmitting similar signals in the future.

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Chemical Synapses

Most common type of synapse in the CNS, where neurotransmitters carry signals between neurons.

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Electrical Synapses

Synapses where the cytoplasm of adjacent cells are directly connected by ion channels; allowing direct transmission of action potentials.

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Presynaptic Terminal

The end of a nerve fiber, containing neurotransmitters, releasing them into the synaptic cleft when stimulated.

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Synaptic Cleft

The gap between two neurons at a synapse, where neurotransmitters are released.

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Postsynaptic Neuron

The neuron receiving the signal at the synapse, it receives signals from the presynaptic terminal

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Lower Brain/Subcortical Level

Areas of the brain below the cortex that control basic life functions and subconscious actions.

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Higher Brain or Cortical Level

The brain's outer layer, responsible for complex mental activities and higher-level processing, including storing memories and thinking.

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Ease of Transmission

The ability of signals to travel across synapses, which can be affected by external signals.

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Regulation by External Signals

Signals from outside the synapse can facilitate (enhance) or inhibit (reduce) signal transmission.

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Metabolic Changes in Neuron Membrane

Increasing excitatory receptors or decreasing inhibitory receptors on a neuron's membrane alters its responsiveness to signals.

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Inhibition Mechanisms (neurons)

Mechanisms that decrease the neuron's excitability by increasing the membrane's negativity.

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Synaptic Transmitters (Small Molecules)

Small molecules that cause rapid responses in neurons, like sensory signals.

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Synaptic Transmitters (Neuropeptides)

Large molecules that cause longer-lasting effects in neurons, like changing receptor number.

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Co-transmission

Simultaneous or sequential release of multiple neurotransmitters from a single neuron, like serotonin and glutamate.

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Resting Membrane Potential

The stable, negative voltage (-65 mV) maintained across a neuron's membrane at rest (compared to skeletal muscle).

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EPSP (Excitatory)

Neurotransmitter release increases membrane permeability to Na+, bringing it closer to the threshold (-45 mV) for firing action potentials.

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IPSP (Inhibitory)

Neurotransmitter release increases membrane permeability to Cl- or K+ to hyperpolarize the membrane, pushing it further from the threshold for firing.

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Spatial Summation

Multiple presynaptic neurons firing simultaneously near each other.

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Synaptic Fatigue

Repetitive neuron stimulation leads to a temporary decrease in postsynaptic neuron firing due to limited neurotransmitter.

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Norepinephrine function

Typically excitatory, but can activate inhibitory receptors; secreted by neurons in the brainstem and hypothalamus, especially the locus ceruleus. Increases wakefulness.

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Dopamine secretion location

Secreted by neurons originating in the substantia nigra, projecting to the striatum of the basal ganglia.

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Glycine's role

An inhibitory neurotransmitter primarily released at spinal cord synapses.

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GABA function

Primarily inhibitory in the adult brain, but can be excitatory during development.

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Glutamate's role

Always excitatory, found at synapses in sensory pathways and cerebral cortex.

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Serotonin's role

Inhibits pain pathways and affects mood/sleep in higher brain regions. Originates from the median raphe.

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Nitric oxide function

Alters intracellular metabolic functions, modifies neuronal excitability; does not directly affect membrane potential.

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Dopamine's action

Usually inhibitory, affecting the basal ganglia, specifically the striatal region.

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Nerve terminal locations of NE

NE released from terminals of neurons originating in the brainstem and hypothalamus; major location: locus ceruleus

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Locations of NE secreting neurons

Large pyramidal cells of motor cortex; neurons in basal ganglia; motor neurons; autonomic preganglionic; PNS Postganglionic; SNS Postganglionic neurons(some)

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Neuron function

Receives input signals (mostly on dendrites and cell body), sends output signals via axon. Signal flow is one-way across synapses.

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Sensory Receptors

Specialized cells that detect and respond to external stimuli, initiating sensory experiences.

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Sensory Input Pathway

Sensory data travels via peripheral nerves to the CNS, relayed to spinal cord, brain stem, cerebellum, thalamus, and cerebral cortex.

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Spinal Cord (Sensory)

Initial processing of sensory information; controls reflexes.

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Reticular Substance

Brain area involved in arousal, involuntary motor functions, and sensory input.

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Synapse

Junction between neurons; allows signal transfer selectively and controls direction.

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Motor Functions

Actions like muscle contractions, internal organ contractions and gland secretions.

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Levels of Skeletal Muscle Control

Different brain regions (spinal cord, brainstem, basal ganglia, cerebellum, cortex) control and refine skeletal muscle actions.

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Integrative Function

Brain filtering, directing and processing sensory information; much is disregarded as irrelevant.

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Ease of Transmission

The ease with which signals pass across synapses; some synapses are easier to transmit signals than others.

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Regulation by External Signals

External signals (like neurotransmitters) can either enhance or block signal transmission through synapses.

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Synaptic Facilitation

Repeated signals strengthen synapses, making them better at transmitting similar signals in the future.

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Chemical Synapses

Most common type of CNS synapse; neurotransmitters carry signals between neurons.

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Electrical Synapses

Synapses where the cytoplasm of adjacent cells is directly connected, allowing immediate action potential transmission.

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Presynaptic Terminal

The end of a nerve fiber; releases neurotransmitters into the synaptic cleft when stimulated.

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Synaptic Cleft

The gap between two neurons at a synapse; The space where neurotransmitters are released.

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Postsynaptic Neuron

The neuron receiving the signal at a synapse.

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Higher Brain Level

The brain's outer layer responsible for higher-level thinking, complex mental activities, and memory storage.

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Lower Brain Level

Brain areas below the cortex controlling basic life functions and subconscious actions

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Metabolic Changes (Neuron)

Increasing excitatory receptors or decreasing inhibitory receptors on the neuron membrane alters responsiveness to signals.

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Inhibition Mechanisms (Neuron)

Methods to reduce neuron excitability by increasing membrane negativity, by increasing Cl- influx and K+ efflux.

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Small-Molecule Transmitters

Rapid-acting neurotransmitters synthesized in the presynaptic terminal, involved in acute nervous system responses like sensory input & motor output

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Neuropeptides

Longer-acting neurotransmitters synthesized in the neuron cell body, impacting prolonged neuronal changes (e.g., receptor #/synapse size)

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Co-transmission

Simultaneous or sequential release of multiple neurotransmitters from a single neuron, affecting complex functions.

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Resting Membrane Potential

A neuron's stable, negative voltage (-65 mV) maintained at rest, crucial for neuronal signaling.

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EPSP (Excitatory)

Neurotransmitters increase membrane permeability to Na+, bringing the neuron closer to firing threshold.

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IPSP (Inhibitory)

Neurotransmitters increase membrane permeability to Cl- or K+, moving the membrane potential further from firing threshold.

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Spatial Summation

Multiple presynaptic neurons firing simultaneously near a target neuron.

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Synaptic Fatigue

Repetitive excitation leads to a temporary decrease in postsynaptic neuron firing due to neurotransmitter depletion.

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Norepinephrine secretion

Norepinephrine (NE) is secreted by neurons in the brainstem and hypothalamus, particularly the locus ceruleus; generally excitatory but can trigger inhibitory responses in some regions.

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Dopamine location

Dopamine is released from neurons originating in the substantia nigra, commonly found in the basal ganglia's striatal area; generally inhibitory.

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Glycine's function

Glycine is an inhibitory neurotransmitter primarily secreted at spinal cord synapses.

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GABA's function

GABA is a neurotransmitter, primarily inhibitory in the adult CNS, but excitatory in development; found in spinal cord, cerebellum, basal ganglia, and cortex.

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Glutamate's role

Glutamate is an excitatory neurotransmitter often associated with sensory processing and cerebral cortex activity.

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Serotonin's function

Released from nuclei in the brain stem's median raphe, serotonin regulates pain, mood, and sleep in various brain regions.

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Nitric Oxide's effect

Nitric oxide is a neurotransmitter that modifies neuronal excitability by altering intracellular metabolic functions, rather than directly impacting membrane potential.

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Dopamine's action

Dopamine typically inhibits neural activity, particularly in the striatum of the basal ganglia.

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Nerve terminals of NE

Norepinephrine (NE) is secreted by the terminals of neurons that originate in the brainstem and hypothalamus, particularly the locus ceruleus.

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NE Secreting Neuron locations

Norepinephrine is secreted by neurons in several locations, like the motor cortex's large pyramids, basal ganglia neurons, motor neurons, and certain autonomic and peripheral nervous system postganglionic neurons.

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