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Questions and Answers
What is the main function of the blood-brain barrier?
What is the primary function of the autonomic nervous system?
What type of neuron transmits information from sensory receptors to the CNS?
What is the term for the gap between two neurons where neurotransmitters are released?
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What is the primary function of the central nervous system?
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What is the term for chemical messengers released by neurons to transmit signals?
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What is the function of interneurons?
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What is the function of motor neurons?
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What is the primary function of the somatic nervous system?
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What is the main function of the nervous system?
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Which type of glial cell is associated with multiple sclerosis?
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What is the cause of multiple sclerosis?
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Which of the following characterizes multiple sclerosis?
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What happens to the skeletal muscle cell when the nervous connection is disrupted?
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What is the difference between a nerve and a tract?
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What happens to the axon when it is damaged?
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What is the difference between white matter and gray matter?
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What is the function of the cell body in axonal regeneration?
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What is the function of the three layers of connective tissue that hold the fibers of a nerve together?
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What is the prognosis for repair of damaged nerve fibers in the CNS?
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What is the primary function of the Central Nervous System (CNS)?
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What is the term for the nerve tissues that lie in the outer region of the nervous system?
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What type of neurons form incoming and outgoing information pathways?
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Which system regulates somatic effectors, such as skeletal muscles?
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What are the two main divisions of the Peripheral Nervous System (PNS)?
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Which direction do efferent neurons transmit information?
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During axonal regeneration, what is the role of the new Schwann cells in the tunnel?
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What is the primary characteristic of multiple sclerosis in relation to the white matter of the CNS?
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What is the primary effect of the disease-modifying drugs used to treat multiple sclerosis?
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Which type of neuron has only one axon and several dendrites?
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What is the main reason why the prognosis for repair of damaged nerve fibers in the CNS is unlikely?
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What is the main function of the perineurium in a nerve?
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What is the relationship between autoimmunity and multiple sclerosis?
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What is the term for the route of signal conduction to and from the CNS?
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What is the primary effect of demyelination in multiple sclerosis?
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Which type of neuron conducts impulses away from the CNS to muscles or glands?
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What is the term for bundles of nerve fibers within the CNS?
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What is the term for the process of removing debris from a damaged nerve fiber?
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Which of the following is NOT a characteristic of Schwann cells?
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What is the primary function of the dendrites and cell body of a neuron?
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What is the term for the small gaps in the myelin sheath formed by Schwann cells?
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Which of the following is a characteristic of myelinated axons?
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What is the term for the region of the axon where nerve impulses are added together?
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What is the term for the region of the axon where vesicles of neurotransmitters are released?
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What is the primary function of the efferent pathway in the Automatic Nervous System?
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Which type of glial cell is responsible for forming the myelin sheath around nerve fibers in the CNS?
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What is the primary function of the Parasympathetic Division of the Automatic Nervous System?
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What is the function of the blood-brain barrier, aside from regulating transport of molecules into the brain?
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What is the primary function of Microglia in the CNS?
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Which type of glial cell is responsible for attaching to the basement membrane of the brain's blood capillaries and forming the blood-brain barrier?
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Study Notes
Overview of the Nervous System
- The nervous system is a complex system that enables the body to respond to internal and external stimuli.
- It consists of two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
Central Nervous System (CNS)
- The CNS consists of the brain and spinal cord.
- It integrates and processes information from sensory receptors and sends out responses to effector organs.
- The CNS is protected by the blood-brain barrier, which regulates the flow of substances into the brain.
Peripheral Nervous System (PNS)
- The PNS consists of nerves that connect the CNS to the rest of the body.
- It is divided into the somatic nervous system and the autonomic nervous system.
- The somatic nervous system transmits sensory information from the body to the CNS and motor signals from the CNS to the body.
- The autonomic nervous system regulates involuntary functions such as heart rate, blood pressure, and digestion.
Functions of the Nervous System
- Control and coordination: The nervous system integrates information from sensory receptors and sends out responses to effector organs.
- Communication: The nervous system enables communication between different parts of the body.
- Regulation: The nervous system regulates various bodily functions such as heart rate, blood pressure, and body temperature.
- Learning and memory: The nervous system enables learning and memory through the formation of neural connections.
Types of Neurons
- Sensory neurons: transmit information from sensory receptors to the CNS.
- Motor neurons: transmit information from the CNS to effector organs.
- Interneurons: integrate and process information within the CNS.
Neurotransmission
- Neurotransmitters: chemical messengers released by neurons to transmit signals.
- Synapse: the gap between two neurons where neurotransmitters are released.
- Postsynaptic potential: the change in electrical potential of a neuron in response to neurotransmitters.
Diseases and Disorders of the Nervous System
- Alzheimer's disease: a degenerative disorder characterized by memory loss and cognitive decline.
- Parkinson's disease: a motor disorder characterized by tremors, rigidity, and bradykinesia.
- Stroke: a condition caused by the interruption of blood flow to the brain.
Overview of the Nervous System
- The nervous system enables the body to respond to internal and external stimuli.
- It consists of two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
Central Nervous System (CNS)
- The CNS consists of the brain and spinal cord.
- It integrates and processes information from sensory receptors and sends out responses to effector organs.
- The CNS is protected by the blood-brain barrier, which regulates the flow of substances into the brain.
Peripheral Nervous System (PNS)
- The PNS consists of nerves that connect the CNS to the rest of the body.
- It is divided into the somatic nervous system and the autonomic nervous system.
- The somatic nervous system transmits sensory information from the body to the CNS and motor signals from the CNS to the body.
- The autonomic nervous system regulates involuntary functions such as heart rate, blood pressure, and digestion.
Functions of the Nervous System
- Control and coordination: integrates information from sensory receptors and sends out responses to effector organs.
- Communication: enables communication between different parts of the body.
- Regulation: regulates various bodily functions such as heart rate, blood pressure, and body temperature.
- Learning and memory: enables learning and memory through the formation of neural connections.
Types of Neurons
- Sensory neurons: transmit information from sensory receptors to the CNS.
- Motor neurons: transmit information from the CNS to effector organs.
- Interneurons: integrate and process information within the CNS.
Neurotransmission
- Neurotransmitters: chemical messengers released by neurons to transmit signals.
- Synapse: the gap between two neurons where neurotransmitters are released.
- Postsynaptic potential: the change in electrical potential of a neuron in response to neurotransmitters.
Diseases and Disorders of the Nervous System
- Alzheimer's disease: a degenerative disorder characterized by memory loss and cognitive decline.
- Parkinson's disease: a motor disorder characterized by tremors, rigidity, and bradykinesia.
- Stroke: a condition caused by the interruption of blood flow to the brain.
Nervous and Endocrine System
- Work together to monitor and respond to changes in the internal and external environment of the body
- Function as a communication system for the body, providing means to control and integrate different functions performed by organs, tissues, and cells
- Unifying body functions allows them to work together to maintain homeostasis and survive
Central Nervous System (CNS)
- Structural and functional center of the nervous system
- Consists of the brain and spinal cord
- Integrates sensory information, evaluates, and initiates an outgoing response
- Cells that begin in the brain or spinal cord but extend through a nerve are not included in the CNS
Peripheral Nervous System (PNS)
- Consists of nerve tissues that lie in the periphery (outer region) of the nervous system
- Includes cranial nerves and spinal nerves
- Cranial nerves originate from the brain or exit through the skull, while spinal nerves originate from the spinal cord and do not exit the skull
Afferent and Efferent
- Afferent division: consists of incoming sensory or afferent pathways
- Efferent division: consists of outgoing motor or efferent pathways
- Both divisions include neurons that form incoming and outgoing information pathways
Somatic and Automatic Nervous Systems
- Somatic Nervous System (SNS):
- Regulates somatic effectors (skeletal muscles)
- Includes motor pathways that directly control skeletal muscles
- Also includes afferent pathways that make up the somatic sensory division
- Automatic Nervous System (ANS):
- Efferent pathways carry information to automatic or visceral (internal) effectors (smooth muscles, cardiac muscles, glands, adipose tissues, and involuntary tissues)
- Governs itself without conscious knowledge
- Divided into two subcategories:
- Sympathetic division: involved in preparing the body to deal with immediate threats to the internal environment
- Parasympathetic division: coordinates the body's typical resting activities
Enteric Nervous System
- Division of the ANS
- Often referred to as the "second brain" in the wall of the gut
- Communicates with both afferent and efferent pathways of the ANS
- Has a mind of its own, with a network of integrators and feedback loops that act somewhat independently
Glia
- Two main types of cells that compose the nervous tissues:
- Neurons: excitable cells that conduct impulses that allow the nervous system to function
- Glia: support cells that retain their capacity for cell division through adulthood
- Five major types of glia:
- Astrocytes: star-shaped, found only in the CNS, and involved in feeding neurons and recycling chemical transmitters
- Microglia: very small cells found in the CNS, involved in phagocytosis and pruning unneeded neurons during brain development
- Ependymal cells: found in the CNS, form thin sheets that line fluid-filled cavities in the brain and spinal cord
- Oligodendrocytes: found in the CNS, involved in myelination and holding nerve fibers together
- Schwann cells: found in the PNS, functional equivalents of oligodendrocytes
Neurons
- Contain almost 100 billion neurons
- Consist of a cell body, one axon, and one or more dendrites
- Dendrites: receive stimuli that initiate nerve signals
- Axon: conducts impulses away from the cell body
- Cell body: contains the nucleus, cytoplasm, and various organelles
- Functional zones of neurons:
- Dendrites and cell body: input zone, receiving nerve stimulation and initiating nerve impulses
- Axon hillock: summation zone, adding together all the nerve impulses arriving from the cell body and dendrites
- Axon: conduction zone, conducting the nerve impulse from the axon hillock to the end of the neuron
- Telodendria and synaptic knobs: output zone, releasing neurotransmitters for possible reception by a nearby neuron or effector cell
Classification of Neurons
- According to the number of extensions from the cell body:
- Multipolar: one axon and several dendrites
- Bipolar: one axon and one highly branched dendrite
- Unipolar: one process extending from the cell body that branches to form a central process and a peripheral process
- According to the direction of impulse conduction:
- Afferent neurons: transmit nerve impulses to the spinal cord or brain
- Efferent neurons: transmit nerve impulses away from the brain or spinal cord to muscles or glands
- Interneurons: conduct impulses between neurons, lying entirely within the CNS
Reflex Arc
- Neurons arranged in a pattern to conduct signals to and from the CNS
- Most common form is a three-neuron arc, consisting of an afferent neuron, an interneuron, and an efferent neuron
- Can also consist of only an afferent and efferent neuron, forming a two-neuron arc
Nerves and Tracts
- Bundles of nerve fibers or axons from many neurons that connect different regions of the nervous system
- Nerves: bundles of peripheral nerve fibers held together by several layers of connective tissue
- Tracts: bundles of nerve fibers within the CNS, without connective tissue coverings
- White and grey matter:
- White matter: myelinated tracts, appearing creamy white in color
- Grey matter: darker in color, composed of cell nuclei in the CNS and ganglia in the PNS
Nervous and Endocrine System
- Work together to monitor and respond to changes in the internal and external environment of the body
- Function as a communication system for the body, providing means to control and integrate different functions performed by organs, tissues, and cells
- Unifying body functions allows them to work together to maintain homeostasis and survive
Central Nervous System (CNS)
- Structural and functional center of the nervous system
- Consists of the brain and spinal cord
- Integrates sensory information, evaluates, and initiates an outgoing response
- Cells that begin in the brain or spinal cord but extend through a nerve are not included in the CNS
Peripheral Nervous System (PNS)
- Consists of nerve tissues that lie in the periphery (outer region) of the nervous system
- Includes cranial nerves and spinal nerves
- Cranial nerves originate from the brain or exit through the skull, while spinal nerves originate from the spinal cord and do not exit the skull
Afferent and Efferent
- Afferent division: consists of incoming sensory or afferent pathways
- Efferent division: consists of outgoing motor or efferent pathways
- Both divisions include neurons that form incoming and outgoing information pathways
Somatic and Automatic Nervous Systems
- Somatic Nervous System (SNS):
- Regulates somatic effectors (skeletal muscles)
- Includes motor pathways that directly control skeletal muscles
- Also includes afferent pathways that make up the somatic sensory division
- Automatic Nervous System (ANS):
- Efferent pathways carry information to automatic or visceral (internal) effectors (smooth muscles, cardiac muscles, glands, adipose tissues, and involuntary tissues)
- Governs itself without conscious knowledge
- Divided into two subcategories:
- Sympathetic division: involved in preparing the body to deal with immediate threats to the internal environment
- Parasympathetic division: coordinates the body's typical resting activities
Enteric Nervous System
- Division of the ANS
- Often referred to as the "second brain" in the wall of the gut
- Communicates with both afferent and efferent pathways of the ANS
- Has a mind of its own, with a network of integrators and feedback loops that act somewhat independently
Glia
- Two main types of cells that compose the nervous tissues:
- Neurons: excitable cells that conduct impulses that allow the nervous system to function
- Glia: support cells that retain their capacity for cell division through adulthood
- Five major types of glia:
- Astrocytes: star-shaped, found only in the CNS, and involved in feeding neurons and recycling chemical transmitters
- Microglia: very small cells found in the CNS, involved in phagocytosis and pruning unneeded neurons during brain development
- Ependymal cells: found in the CNS, form thin sheets that line fluid-filled cavities in the brain and spinal cord
- Oligodendrocytes: found in the CNS, involved in myelination and holding nerve fibers together
- Schwann cells: found in the PNS, functional equivalents of oligodendrocytes
Neurons
- Contain almost 100 billion neurons
- Consist of a cell body, one axon, and one or more dendrites
- Dendrites: receive stimuli that initiate nerve signals
- Axon: conducts impulses away from the cell body
- Cell body: contains the nucleus, cytoplasm, and various organelles
- Functional zones of neurons:
- Dendrites and cell body: input zone, receiving nerve stimulation and initiating nerve impulses
- Axon hillock: summation zone, adding together all the nerve impulses arriving from the cell body and dendrites
- Axon: conduction zone, conducting the nerve impulse from the axon hillock to the end of the neuron
- Telodendria and synaptic knobs: output zone, releasing neurotransmitters for possible reception by a nearby neuron or effector cell
Classification of Neurons
- According to the number of extensions from the cell body:
- Multipolar: one axon and several dendrites
- Bipolar: one axon and one highly branched dendrite
- Unipolar: one process extending from the cell body that branches to form a central process and a peripheral process
- According to the direction of impulse conduction:
- Afferent neurons: transmit nerve impulses to the spinal cord or brain
- Efferent neurons: transmit nerve impulses away from the brain or spinal cord to muscles or glands
- Interneurons: conduct impulses between neurons, lying entirely within the CNS
Reflex Arc
- Neurons arranged in a pattern to conduct signals to and from the CNS
- Most common form is a three-neuron arc, consisting of an afferent neuron, an interneuron, and an efferent neuron
- Can also consist of only an afferent and efferent neuron, forming a two-neuron arc
Nerves and Tracts
- Bundles of nerve fibers or axons from many neurons that connect different regions of the nervous system
- Nerves: bundles of peripheral nerve fibers held together by several layers of connective tissue
- Tracts: bundles of nerve fibers within the CNS, without connective tissue coverings
- White and grey matter:
- White matter: myelinated tracts, appearing creamy white in color
- Grey matter: darker in color, composed of cell nuclei in the CNS and ganglia in the PNS
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Description
Learn about the structure and function of the nervous system, including the central and peripheral nervous systems, and their role in responding to internal and external stimuli.
