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Questions and Answers
In serial processing, an incoming signal is divided and sent through multiple pathways simultaneously.
In serial processing, an incoming signal is divided and sent through multiple pathways simultaneously.
False
Amplification within a neuronal pool increases the strength of the incoming signal and transmits it in numerous directions.
Amplification within a neuronal pool increases the strength of the incoming signal and transmits it in numerous directions.
True
Convergence occurs when a single incoming signal results in multiple, separate excitatory signals.
Convergence occurs when a single incoming signal results in multiple, separate excitatory signals.
False
After-discharge is a short-lasting output that occurs only when an incoming signal is still present.
After-discharge is a short-lasting output that occurs only when an incoming signal is still present.
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Synaptic after-discharge is caused by long-acting synaptic transmitter substances at the surface of postsynaptic neurons.
Synaptic after-discharge is caused by long-acting synaptic transmitter substances at the surface of postsynaptic neurons.
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Reverberatory circuits are a mechanism for after-discharge where signal flow is strictly one-way without any feedback loops.
Reverberatory circuits are a mechanism for after-discharge where signal flow is strictly one-way without any feedback loops.
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Inhibitory mechanisms in the nervous system help prevent continuous re-excitation and uncontrolled signals throughout the brain.
Inhibitory mechanisms in the nervous system help prevent continuous re-excitation and uncontrolled signals throughout the brain.
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Inhibitory interneurons prevent signals from spreading diffusely by synapsing at the axons or terminals of adjacent less excited neurons.
Inhibitory interneurons prevent signals from spreading diffusely by synapsing at the axons or terminals of adjacent less excited neurons.
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Recurrent inhibition occurs when a collateral terminal from a pathway excites an inhibitory interneuron, which then inhibits the initial excitatory neuron of a different pathway.
Recurrent inhibition occurs when a collateral terminal from a pathway excites an inhibitory interneuron, which then inhibits the initial excitatory neuron of a different pathway.
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The nervous system can adjust the sensitivity of information pathways through both short-term fatigue mechanisms and long-term receptor downgrading or upgrading.
The nervous system can adjust the sensitivity of information pathways through both short-term fatigue mechanisms and long-term receptor downgrading or upgrading.
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Fatigue mechanism leads to decreased sensitivity of overused pathways and decreased sensitivity of underused pathways.
Fatigue mechanism leads to decreased sensitivity of overused pathways and decreased sensitivity of underused pathways.
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Long-term adjustments in pathway sensitivity are facilitated by downgrading or upgrading of synaptic receptors, impacting sensitivities of the synapses.
Long-term adjustments in pathway sensitivity are facilitated by downgrading or upgrading of synaptic receptors, impacting sensitivities of the synapses.
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The somatosensory system is a sensory system associated with the environmental conditions that effect the body from the outside world.
The somatosensory system is a sensory system associated with the environmental conditions that effect the body from the outside world.
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Sensory receptors convert environmental signals into neural signals by a process called action reduction.
Sensory receptors convert environmental signals into neural signals by a process called action reduction.
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Mechanoreceptors detect changes in temperature, sound, and chemical concentrations.
Mechanoreceptors detect changes in temperature, sound, and chemical concentrations.
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Proprioceptors monitor the position of joints, the tension in tendons, and also can measure the level of blood glucose.
Proprioceptors monitor the position of joints, the tension in tendons, and also can measure the level of blood glucose.
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Receptor adaptation is a progressive increase in receptor response to a constant stimulus.
Receptor adaptation is a progressive increase in receptor response to a constant stimulus.
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Phasic receptors send constant signals to the brain for many minutes or hours.
Phasic receptors send constant signals to the brain for many minutes or hours.
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Tonic receptors adapt quickly to continuous stimulation.
Tonic receptors adapt quickly to continuous stimulation.
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The macula in the vestibular apparatus is an example of a phasic receptor.
The macula in the vestibular apparatus is an example of a phasic receptor.
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A sensory unit consists of multiple sensory axons.
A sensory unit consists of multiple sensory axons.
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The receptive field of a sensory unit is the area where a stimulus produces a response.
The receptive field of a sensory unit is the area where a stimulus produces a response.
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Recruitment of sensory units involves reduction in the number of active sensory units as stimulus intensity increases.
Recruitment of sensory units involves reduction in the number of active sensory units as stimulus intensity increases.
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Overlapping of sensory units only happens within the same receptor type.
Overlapping of sensory units only happens within the same receptor type.
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Golgi tendon apparatuses are classified as phasic receptors
Golgi tendon apparatuses are classified as phasic receptors
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The number of impulses transmitted by phasic receptors is related to the change rate of the stimulus.
The number of impulses transmitted by phasic receptors is related to the change rate of the stimulus.
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A sudden painful stimulus gives a single pain sensation.
A sudden painful stimulus gives a single pain sensation.
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Mechanosensitive pain receptors are primarily excited by extreme temperatures.
Mechanosensitive pain receptors are primarily excited by extreme temperatures.
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Thermosensitive pain receptors are sensitive to extreme heat or cold.
Thermosensitive pain receptors are sensitive to extreme heat or cold.
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Chemosensitive pain receptors are only activated by direct damage to nerve fibers.
Chemosensitive pain receptors are only activated by direct damage to nerve fibers.
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Aspirin reduces pain by increasing the production of prostaglandins.
Aspirin reduces pain by increasing the production of prostaglandins.
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Ischemia can cause pain due to the accumulation of lactic acid in tissues.
Ischemia can cause pain due to the accumulation of lactic acid in tissues.
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Muscle spasm can directly stimulate chemosensitive pain receptors.
Muscle spasm can directly stimulate chemosensitive pain receptors.
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Prostaglandins reduce the sensitization of pain nerve fibers.
Prostaglandins reduce the sensitization of pain nerve fibers.
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Substance P, histamine, and potassium ions are all examples of chemicals that can stimulate chemosensitive pain receptors.
Substance P, histamine, and potassium ions are all examples of chemicals that can stimulate chemosensitive pain receptors.
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Referred pain is experienced in the exact same location as the source of the tissue damage.
Referred pain is experienced in the exact same location as the source of the tissue damage.
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Stimulation of large A fibers opens the pain gate by exciting inhibitory interneurons.
Stimulation of large A fibers opens the pain gate by exciting inhibitory interneurons.
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Acupuncture inhibits pain signals by stimulating large sensory fibers that project to the dorsal column of the spinal cord, which then results in decreased transmission of pain signals.
Acupuncture inhibits pain signals by stimulating large sensory fibers that project to the dorsal column of the spinal cord, which then results in decreased transmission of pain signals.
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Nociceptors are only stimulated when the temperature is below 10°C or above 45°C.
Nociceptors are only stimulated when the temperature is below 10°C or above 45°C.
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Warm receptors are stimulated by Aδ fibers and C fibers, while cold receptors are only stimulated by C fibers.
Warm receptors are stimulated by Aδ fibers and C fibers, while cold receptors are only stimulated by C fibers.
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An increase in the stimulated surface area makes it difficult to determine gradations of temperature.
An increase in the stimulated surface area makes it difficult to determine gradations of temperature.
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Study Notes
Nervous System Functions
- Coordinate the activities of other systems (along with the endocrine system) through senses and responses to internal and external events; maintaining homeostasis.
- Store experiences (memory) and establish patterns of response based on prior experiences (learning).
Functional Levels of the CNS
- Intercommunication between the external and internal environments is mediated by the sensory-somatic and autonomic peripheral nervous systems, respectively.
- The CNS can be divided into three functional levels: spinal cord, lower brain (subcortical), and higher brain (cortical).
Spinal Cord Level
- Conduit for signals between the periphery and the brain.
- Contains reflex control centers.
Lower Brain Level (Subcortical)
- Controls subconscious bodily functions, such as arterial pressure, respiration, and emotional responses.
Higher Brain Level (Cortical)
- Transforms lower CNS functions into precise operations.
- Essential for thought processes.
- Large memory storehouse.
Neuronal Pools
- Interconnected neurons.
- Process signals in specialized ways, such as serial or parallel processing or amplification.
- Input signals can excite, inhibit, or facilitate neurons within the pool.
- Convergence allows the summation of multiple input signals.
Synaptic After-discharge
- Prolonged output discharge after an incoming signal.
- Caused by persistent synaptic transmitter substances or parallel signals converging on an output neuron or reverberation of neurons.
Stabilization of Neuronal Circuits
- Critical to prevent uncontrolled signal transmission.
- Inhibitory mechanisms prevent widespread re-excitation.
Presynaptic Inhibition
- Inhibition occurs before the signal reaches the synapse.
- Mechanisms include opening Cl and K ion channels, blocking Ca channels.
Postsynaptic Inhibition
- Inhibition originates at the postsynaptic membrane.
- Can be due to IPSP generation or synaptic fatigue.
Anatomical Inhibition
- Lateral Inhibition: Inhibitory interneurons prevent signal spreading to neighboring neurons.
- Recurrent Inhibition: Collateral signals excite inhibitory interneurons, leading to inhibition of the initial excitatory neuron.
Adjustment of Pathway Sensitivity
- Fatigue Mechanism (Short-term): Overused pathways become less sensitive, while underused pathways become more sensitive.
- Downgrading/Upgrading (Long-term): Receptor proteins adjust to increase or decrease sensitivity dependent on usage.
Sensory Receptors
- Specialized cells or neurons that transduce environmental signals (mechanical, light, sound, chemical, temperature) into neural signals (action potentials).
- Five types based on the stimulus: mechanoreceptors, thermoreceptors, nociceptors, electromagnetic receptors, and chemoreceptors.
- Types associated with somatosensory system: somatic senses (tactile, proprioceptive, etc.), special senses (vision, smell), and visceral sensations.
General properties of receptors
- Sensitivity: High specificity for a particular stimulus.
- Specificity: Transmit only one type of sensory information.
- Receptor potential/generator potential: Produce a graded potential in response to a stimulus, which can trigger an action potential.
Adaptation of Receptors (Desensitization)
- Tonic Receptors: Slowly and incompletely adapt (e.g., pain receptors, muscle spindles).
- Phasic Receptors: Rapidly adapt (e.g., pressure receptors, smell).
Sensory Units & Receptive Fields
- A sensory unit has a sensory neuron and the receptor regions whose activation affects it.
- Receptive fields: Area stimulated with input leading to activation of sensory unit.
- Increased recruitment of receptors with stronger stimulation.
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Description
Explore the intricate functions of the nervous system, including its role in coordinating bodily activities and maintaining homeostasis. This quiz covers the functional levels of the CNS, focusing on the spinal cord, lower brain, and higher brain, along with their specific roles and operations.
