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Questions and Answers
Which of the following correctly describes the components of the central nervous system (CNS)?
Which of the following correctly describes the components of the central nervous system (CNS)?
What are the parts of the nervous system that include sensory and motor components classified as?
What are the parts of the nervous system that include sensory and motor components classified as?
Which of the following correctly distinguishes between structures in the brain?
Which of the following correctly distinguishes between structures in the brain?
What is the primary function of the meningeal layers surrounding the brain?
What is the primary function of the meningeal layers surrounding the brain?
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Which structure is primarily associated with cauda equina syndrome?
Which structure is primarily associated with cauda equina syndrome?
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What is the primary function of glial cells in the nervous system?
What is the primary function of glial cells in the nervous system?
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Which type of neuron carries impulses from sensory receptors to the central nervous system?
Which type of neuron carries impulses from sensory receptors to the central nervous system?
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What role do Schwann cells play in the peripheral nervous system?
What role do Schwann cells play in the peripheral nervous system?
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Which of the following statements accurately describes myelin sheaths?
Which of the following statements accurately describes myelin sheaths?
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What is the result of Multiple Sclerosis in terms of neurological function?
What is the result of Multiple Sclerosis in terms of neurological function?
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What type of neural structure is referred to as ganglia?
What type of neural structure is referred to as ganglia?
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What autoimmune condition is characterized by the immune system attacking myelin in the CNS?
What autoimmune condition is characterized by the immune system attacking myelin in the CNS?
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Which type of glial cell in the CNS is primarily involved in maintaining the blood-brain barrier?
Which type of glial cell in the CNS is primarily involved in maintaining the blood-brain barrier?
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Which division of the nervous system includes cranial and spinal nerves?
Which division of the nervous system includes cranial and spinal nerves?
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What is the primary structural feature of white matter in the central nervous system?
What is the primary structural feature of white matter in the central nervous system?
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During early brain development, which part forms the largest region of the brain?
During early brain development, which part forms the largest region of the brain?
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Which layer of the meninges directly adheres to the surface of the brain?
Which layer of the meninges directly adheres to the surface of the brain?
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What is the correct description of association fibers in the brain?
What is the correct description of association fibers in the brain?
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What distinct function do efferent neurons provide in the nervous system?
What distinct function do efferent neurons provide in the nervous system?
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Which of the following accurately describes the function of astrocytes in the CNS?
Which of the following accurately describes the function of astrocytes in the CNS?
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What is a primary characteristic of myelin sheaths in the peripheral nervous system?
What is a primary characteristic of myelin sheaths in the peripheral nervous system?
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How do microglia contribute to the health of the nervous system?
How do microglia contribute to the health of the nervous system?
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Which type of glial cell in the PNS is responsible for surrounding neuron cell bodies?
Which type of glial cell in the PNS is responsible for surrounding neuron cell bodies?
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Which condition is characterized by the immune-mediated destruction of myelin in the peripheral nervous system?
Which condition is characterized by the immune-mediated destruction of myelin in the peripheral nervous system?
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What key role do Nissl bodies play within neurons?
What key role do Nissl bodies play within neurons?
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What is the primary function of glial cells in relation to neurons?
What is the primary function of glial cells in relation to neurons?
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Study Notes
Nervous System Divisions
-
Anatomical (structural):
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Central nervous system (CNS): Brain & Spinal Cord
- White matter: Contains myelinated axons
- Grey matter: Contains neuronal cell bodies and dendrites
- Protection: Meninges (protective membranes), Cerebrospinal fluid (CSF)
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Peripheral nervous system (PNS): Cranial nerves (12 pairs) & Spinal nerves (31 pairs)
- Ganglia: Collections of neuronal cell bodies outside the CNS
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Central nervous system (CNS): Brain & Spinal Cord
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Functional:
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Somatic nervous system: Controls voluntary movements
- Motor components: Carry signals from CNS to muscles
- Sensory components: Carry signals from sensory receptors to CNS
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Autonomic nervous system (ANS): Controls involuntary functions (heart rate, digestion, breathing)
- Sympathetic NS: "Fight or flight" response
- Parasympathetic NS: Rest and digest activities
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Somatic nervous system: Controls voluntary movements
CNS & PNS
- PNS serves as a communication link between the CNS and the rest of the body.
Nervous Tissue
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Neurons are the basic units of the nervous system.
- Conduct nerve impulses
- Transfer information
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Glial cells provide support and protection for neurons
- Nurture and protect neurons
- Enhance the efficiency of information transfer
Neuron Structure
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Receptor: Receives signals from other neurons or sensory receptors
- Dendrites: Branching processes that receive input from other neurons
- Cell body membranes: Contains the nucleus and other organelles
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Conduction:
- Axon: Long, slender process that carries nerve impulses away from the cell body
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Transmitter:
- Axon terminal: Releases neurotransmitters to communicate with other neurons.
Staining
- Nissl bodies are found within the cell body which allow for the staining of neurons under a microscope.
Neuron Types
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Based on the arrangement of cell body processes:
- Unipolar: Single process that divides into two branches
- Bipolar: Two processes: one dendrite and one axon
- Multipolar: Multiple dendrites and a single axon
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Based on function:
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Afferent (Sensory) neurons: Carry signals from sensory receptors to the CNS
- 3 neuron pathways: Ends in the post-central gyrus (sensory cortex)
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Efferent (Motor) neurons: Carry signals from the CNS to effector cells (muscles, glands)
- 2 neuron pathways: Starts in the pre-central gyrus (motor cortex)
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Afferent (Sensory) neurons: Carry signals from sensory receptors to the CNS
Glial Cells
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Six types:
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Four in the CNS:
- Astrocytes: Provide structural support, regulate blood flow, and contribute to the blood-brain barrier
- Ependymal Cells: Line the ventricles of the brain and central canal of the spinal cord, produce cerebrospinal fluid (CSF)
- Microglia: Immune cells of the CNS, remove debris and pathogens
- Oligodendrocytes: Form myelin sheaths around axons
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Two in the PNS:
- Satellite cells: Surround neuron cell bodies in ganglia
- Schwann cells: Form myelin sheaths around axons in the PNS
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Four in the CNS:
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NOTE: Glial cells are responsible for the majority of brain tumours called Gliomas.
Myelin Sheaths
- Segmented structures: Composed of the lipoprotein myelin
- Surround thicker axons: Increase the speed of impulse conduction
- Form an insulating layer: Prevents the loss of electrical signals
Myelin Sheaths in the PNS
- Formed by Schwann cells: Wrap around an axon in concentric layers
- Cover the axon in a tightly packed coil of membranes: This forms the myelin sheath
Clinical Correlates
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Multiple Sclerosis: Autoimmune disease where the immune system attacks the myelin around axons in the CNS
- Cause: Incompletey understood
- Effects: Slowing of axonal conduction and neurological dysfunction
- Symptoms: Plaques of demyelination
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Guillain-Barré syndrome: Immune-mediated destruction of myelin in the PNS
- Trigger: Often follows an infection
Ganglia
- Collection of cell bodies of neurons present outside the CNS:
-
Two types:
- Spinal ganglia: Present at the course of the dorsal root of spinal nerves
- Autonomic ganglia: Part of the autonomic nervous system
This could be a good start to help you study. Make sure to use this information along with your textbook and lecture notes to fully understand the complex anatomy of the nervous system.
Nervous System Divisions
- Anatomical: Central Nervous System (CNS) and Peripheral Nervous System (PNS)
- Functional: Somatic Nervous System (SNS) and Autonomic Nervous System (ANS)
CNS
- Includes brain and spinal cord
- Composed of white and grey matter
- Protected by meninges
PNS
- Includes cranial nerves (12 pairs) and spinal nerves (31 pairs)
- Also includes ganglia
ANS
- Sympathetic and parasympathetic branches
What is the Nervous System Made Of?
- Neurons: Nerve cells responsible for conducting nerve impulses and transferring information
- Glial Cells: Supporting cells that nurture, protect and enhance the efficiency of information transfer
Neuron Structure
- Receptor: Responsible for receiving information
- Dendrites: Receive signals from other neurons
- Cell Body: Contains the nucleus and other organelles
- Axon: Conducts nerve impulses away from the cell body
- Axon Terminal: Releases neurotransmitters to signal other cells
Nissl Body Staining
- A technique used to visualize neuronal cell bodies
Types of Neurons (Based on Arrangement of Cell Body Processes)
- Unipolar Neuron: E.g., Sensory neurons
- Bipolar Neuron: E.g., Retinal neurons
- Multipolar Neuron: E.g., Motor neurons and Interneurons
Types of Neurons (Based on Function)
- Afferent (Sensory) Neurons: Carry impulses from sensory receptors to the CNS
- Efferent (Motor) Neurons: Carry impulses from the CNS to effector cells (muscles and glands)
Glial Cells
- Six types of glial cells, four in the CNS and two in the PNS
- Provide support and protection for neurons
- Gliomas: Brain tumors that often arise from glial cells
Glial Cells in the CNS
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Astrocytes: Structure & support, Blood Brain Barrier (BBB)
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Ependymal cells: Secrete Cerebrospinal Fluid (CSF)
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Microglia: Immune system function of the CNS
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Oligodendrocytes: Myelination in the CNS
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Schwann Cells: Myelination in the PNS
Myelin Sheath
- Segmented structure made of lipoprotein myelin
- Insulates thicker axons, increasing the speed of impulse conduction
Myelin Sheath in the PNS
- Formed by Schwann cells
- Wrap around axons in concentric layers
Clinical Correlates
- Multiple Sclerosis: Autoimmune disease targeting myelin in the CNS causing demyelination and neurological dysfunction
- Guillain-Barre syndrome: Autoimmune attack on myelin in the PNS, triggered by infection
Ganglia
- Collection of neuron cell bodies located outside the CNS
- Spinal ganglia: Associated with dorsal roots of spinal nerves
- Autonomic ganglia: Associated with the ANS
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Description
Explore the intricate divisions of the nervous system, focusing on both the anatomical and functional aspects. This quiz covers the Central and Peripheral nervous systems, their structures, protective mechanisms, and roles in voluntary and involuntary functions.
