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Questions and Answers
What is the primary function of neurons within the nervous system?
What is the primary function of neurons within the nervous system?
What is the term for the junction between two neurons?
What is the term for the junction between two neurons?
Which part of the neuron is primarily responsible for receiving signals?
Which part of the neuron is primarily responsible for receiving signals?
Which of the following best describes the speed range at which neurons can transmit nerve impulses?
Which of the following best describes the speed range at which neurons can transmit nerve impulses?
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What structure is part of the neuron’s cell body?
What structure is part of the neuron’s cell body?
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What is the primary role of interneurons in the nervous system?
What is the primary role of interneurons in the nervous system?
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Which division of the peripheral nervous system is responsible for voluntary muscle control?
Which division of the peripheral nervous system is responsible for voluntary muscle control?
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What type of neurons transmit nerve impulses from the CNS to effector organs?
What type of neurons transmit nerve impulses from the CNS to effector organs?
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Which subdivision of the peripheral nervous system is known for its 'fight-or-flight' response?
Which subdivision of the peripheral nervous system is known for its 'fight-or-flight' response?
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Which aspect of the autonomic nervous system is primarily concerned with 'rest-and-digest' activities?
Which aspect of the autonomic nervous system is primarily concerned with 'rest-and-digest' activities?
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What is the initial segment of the axon?
What is the initial segment of the axon?
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What type of neurons are involved in the involuntary control of smooth muscle and glands?
What type of neurons are involved in the involuntary control of smooth muscle and glands?
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Where are nerve impulses initiated in most neurons?
Where are nerve impulses initiated in most neurons?
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Which component of the peripheral nervous system facilitates sensory input from visceral receptors?
Which component of the peripheral nervous system facilitates sensory input from visceral receptors?
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What is the enteric nervous system primarily associated with?
What is the enteric nervous system primarily associated with?
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What is contained within the synaptic end-bulbs and varicosities?
What is contained within the synaptic end-bulbs and varicosities?
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What do we call the synapse between a motor neuron and a muscle fiber?
What do we call the synapse between a motor neuron and a muscle fiber?
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Which of the following best describes the synaptic cleft?
Which of the following best describes the synaptic cleft?
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Which of the following is NOT a neurotransmitter mentioned?
Which of the following is NOT a neurotransmitter mentioned?
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What feature helps transmit nerve impulses toward the synapse?
What feature helps transmit nerve impulses toward the synapse?
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Most axons are characterized by which feature?
Most axons are characterized by which feature?
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What is the primary role of sensory neurons in the nervous system?
What is the primary role of sensory neurons in the nervous system?
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Which component is NOT considered part of the nervous system?
Which component is NOT considered part of the nervous system?
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Which statement best describes neuroglia?
Which statement best describes neuroglia?
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Gray matter primarily consists of which type of neural structure?
Gray matter primarily consists of which type of neural structure?
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Which function best describes the role of the nervous system's organization?
Which function best describes the role of the nervous system's organization?
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Neurogenesis primarily refers to what process?
Neurogenesis primarily refers to what process?
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In terms of classification, what distinguishes a sensory neuron from other types?
In terms of classification, what distinguishes a sensory neuron from other types?
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Which of the following is a characteristic feature of neuronal circuits?
Which of the following is a characteristic feature of neuronal circuits?
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What is the primary function of Schwann cells in the peripheral nervous system (PNS)?
What is the primary function of Schwann cells in the peripheral nervous system (PNS)?
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Which statement accurately describes the composition of gray matter in the central nervous system (CNS)?
Which statement accurately describes the composition of gray matter in the central nervous system (CNS)?
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What are nodes of Ranvier?
What are nodes of Ranvier?
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In terms of neuronal circuits, what best describes a diverging circuit?
In terms of neuronal circuits, what best describes a diverging circuit?
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Which type of neuroglia primarily provides support to neurons in PNS ganglia?
Which type of neuroglia primarily provides support to neurons in PNS ganglia?
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What color does white matter appear and why?
What color does white matter appear and why?
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Which statement is true regarding unmyelinated axons?
Which statement is true regarding unmyelinated axons?
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What characterizes a reverberating circuit?
What characterizes a reverberating circuit?
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Study Notes
Overview of the Nervous System
- The nervous system and endocrine system work together as the body's primary regulatory systems.
- Neurology studies the nervous system's normal function and potential disorders.
- The central nervous system (CNS) consists of the brain and spinal cord
- The peripheral nervous system (PNS) comprises cranial nerves from the brain and spinal nerves from the spinal cord.
- The PNS carries sensory (afferent) signals towards the CNS and motor (efferent) signals away from the CNS.
Organization of the Nervous System
- The PNS is categorized into three main parts: the somatic nervous system (SNS), the autonomic nervous system (ANS), and the enteric nervous system (ENS).
- The voluntary SNS conveys sensory information to the CNS and delivers motor commands to skeletal muscles.
- The involuntary ANS has sensory functions for internal organs and motor functions for smooth muscle, cardiac muscle, and glands.
- The sympathetic division of the ANS supports activities like “fight-or-flight” responses.
- The parasympathetic division of the ANS focuses on “rest-and-digest” functions.
- The ENS, the “brain of the gut”, regulates gastrointestinal functions.
Histology of Nervous Tissue
- The nervous system is composed of neurons and neuroglia.
- Neurons are responsible for most of the nervous system's specialized activities.
- Neuroglia play a supportive role, nourishing and protecting neurons, while maintaining the interstitial fluid surrounding neurons.
- Neurons exhibit excitability, which means they can transform a stimulus into a nerve impulse or action potential.
Structure of a Neuron
- Most neurons have a cell body (soma), dendrites, and an axon.
- The cell body contains the nucleus and various organelles like Nissl bodies, neurofibrils, and microtubules.
- Dendrites are branched, unmyelinated processes that receive signals from other neurons.
- The axon is a long, potentially myelinated process that transmits signals away from the cell body.
- The axon hillock is where the axon joins the cell body.
- The initial segment is the first part of the axon.
- The trigger zone (at the junction of the axon hillock and initial segment) is where nerve impulses are initiated.
- Axoplasm is the cytoplasm within the axon, surrounded by the axolemma (plasma membrane).
- Axon collaterals may branch off the axon.
- Axon terminals, at the end of the axon and its collaterals, release neurotransmitters.
- Synaptic end bulbs, or varicosities, contain synaptic vesicles storing neurotransmitter molecules.
Synaptic Transmission Processes
- The synapse is the communication point between neurons or between a neuron and a target cell.
- The presynaptic neuron liberates neurotransmitters at the synapse, which act on the postsynaptic cell.
- The synaptic cleft is the space between the presynaptic and postsynaptic cells.
- There are many different neurotransmitters, such as acetylcholine (ACh), glutamate, aspartate, glycine, norepinephrine (NE), dopamine (DA), serotonin, endorphins, nitric oxide (NO), and more.
Neuroglia Cells
- Schwann cells in the PNS form myelin sheaths around axons.
- The neurolemma (sheath of Schwann) is the outer layer of the Schwann cell, containing the nucleus and cytoplasm.
- Nodes of Ranvier are the unmyelinated gaps between Schwann cells on a myelinated axon.
- Satellite cells support neurons within PNS ganglia.
Gray and White Matter
- Gray matter in the CNS contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia.
- White matter consists of myelinated neuronal processes.
- In the spinal cord, gray matter forms a butterfly-shaped core surrounded by white matter.
- The brain has an outer layer of gray matter (cerebrum and cerebellum) and internal masses of gray matter called nuclei, containing neuronal cell bodies.
- Nerves and tracts are primarily composed of white matter.
Neuronal Circuits
- Neuronal circuits are complex networks of neurons in the CNS.
- Simple series circuits involve a sequence of neurons, each transmitting signals to the next.
- More complex circuits include diverging circuits (one neuron to multiple others), converging circuits (multiple neurons to one), and reverberating circuits (cyclic signal transmission).
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Description
This quiz covers the structure and function of the nervous system, including the central and peripheral nervous systems. It explores the organization of the nervous system, detailing the somatic, autonomic, and enteric nervous systems. Test your knowledge on how these systems work together to regulate bodily functions.
