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Questions and Answers
What is the formation of myelin in the Central Nervous System attributed to?
What is the formation of myelin in the Central Nervous System attributed to?
Where is myelin present along the length of a nerve fiber?
Where is myelin present along the length of a nerve fiber?
Which of the following structures are primarily involved in the formation of myelin sheath in the CNS?
Which of the following structures are primarily involved in the formation of myelin sheath in the CNS?
What characteristic best describes the presence of myelin along nerve fibers?
What characteristic best describes the presence of myelin along nerve fibers?
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Which of the following is NOT involved in the formation of myelin in the Central Nervous System?
Which of the following is NOT involved in the formation of myelin in the Central Nervous System?
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What is the primary function of the cell body in a neuron?
What is the primary function of the cell body in a neuron?
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Which part of the neuron is primarily responsible for receiving signals?
Which part of the neuron is primarily responsible for receiving signals?
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Which statement is true regarding the axon in a neuron?
Which statement is true regarding the axon in a neuron?
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What are the three basic parts of a neuron?
What are the three basic parts of a neuron?
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How does the structure of dendrites facilitate their function?
How does the structure of dendrites facilitate their function?
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What is the primary composition of the myelin sheath?
What is the primary composition of the myelin sheath?
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Which type of cells are responsible for the formation of the myelin sheath in the Peripheral Nervous System?
Which type of cells are responsible for the formation of the myelin sheath in the Peripheral Nervous System?
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What is a key characteristic of the myelin sheath?
What is a key characteristic of the myelin sheath?
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Which of the following statements about the myelin sheath is true?
Which of the following statements about the myelin sheath is true?
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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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What is produced in the cell body of a neuron in response to incoming signals?
What is produced in the cell body of a neuron in response to incoming signals?
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Which part of the neuron is primarily involved in receiving signals?
Which part of the neuron is primarily involved in receiving signals?
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What role do graded potentials play in neuron signaling?
What role do graded potentials play in neuron signaling?
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What is the primary function of the neuron cell body?
What is the primary function of the neuron cell body?
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Where are graded potentials mainly generated within the neuron structure?
Where are graded potentials mainly generated within the neuron structure?
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What is the main mechanism by which current flows along myelinated fibers?
What is the main mechanism by which current flows along myelinated fibers?
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What does the term 'saltare', which refers to the mechanism of action potential in myelinated fibers, mean?
What does the term 'saltare', which refers to the mechanism of action potential in myelinated fibers, mean?
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Where does the action potential predominantly occur in myelinated fibers?
Where does the action potential predominantly occur in myelinated fibers?
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What is the effect of myelination on the speed of impulse conduction?
What is the effect of myelination on the speed of impulse conduction?
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Which statement accurately describes the process of saltatory conduction?
Which statement accurately describes the process of saltatory conduction?
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What occurs when the axonal membrane is not covered with myelin sheath?
What occurs when the axonal membrane is not covered with myelin sheath?
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What effect does exposure to Extra-Cellular Fluid (ECF) have on the axonal membrane?
What effect does exposure to Extra-Cellular Fluid (ECF) have on the axonal membrane?
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Why might non-myelinated axons conduct impulses differently than myelinated axons?
Why might non-myelinated axons conduct impulses differently than myelinated axons?
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Which factor is primarily responsible for increasing the speed of conduction of impulses in non-myelinated axons?
Which factor is primarily responsible for increasing the speed of conduction of impulses in non-myelinated axons?
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What is a characteristic feature of axons that lack a myelin sheath?
What is a characteristic feature of axons that lack a myelin sheath?
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What is the outcome for axons myelinated by Oligodendrocytes in the CNS?
What is the outcome for axons myelinated by Oligodendrocytes in the CNS?
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Which of the following statements accurately describes Oligodendrocytes?
Which of the following statements accurately describes Oligodendrocytes?
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What distinguishes myelinated axons in the CNS from those in the peripheral nervous system (PNS)?
What distinguishes myelinated axons in the CNS from those in the peripheral nervous system (PNS)?
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What is one major consequence of the lack of regeneration in myelinated axons of the CNS?
What is one major consequence of the lack of regeneration in myelinated axons of the CNS?
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In terms of recovery, how do Oligodendrocytes impact the healing process after CNS injuries?
In terms of recovery, how do Oligodendrocytes impact the healing process after CNS injuries?
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Study Notes
Neuron Structure
- Neurons, also known as nerve cells, are the basic units of the nervous system.
- They consist of three main parts:
- Cell body: Contains the nucleus and organelles, responsible for the neuron's metabolic functions.
- Dendrites: Branching extensions that receive signals from other neurons.
- Axon: A long, slender projection that transmits signals away from the cell body.
Myelination
- Myelin sheath: A fatty insulating layer that covers the axons of some neurons.
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Function of myelin sheath: Increases the speed of nerve impulse conduction.
- In the central nervous system (CNS): Myelin is formed by oligodendrocytes.
- In the peripheral nervous system (PNS): Myelin is formed by Schwann cells.
- Unmyelinated regions: Gaps in the myelin sheath called Nodes of Ranvier.
- Saltatory conduction: The jumping of nerve impulses from one node of Ranvier to the next, increasing conduction speed.
Myelination and Nerve Conduction Velocity (NCV)
- Myelination significantly increases the NCV.
- In myelinated fibers, the action potential (nerve impulse) only needs to be generated at the Nodes of Ranvier.
- This "jumping" of impulses from node to node (saltatory conduction) allows for much faster nerve impulse transmission compared to unmyelinated fibers.
Neuron Input Zone
- Dendrites and cell bodies serve as the input zone of a neuron
Graded Potentials
- Graded potentials are produced in response to incoming signals at the cell body
Myelin Sheath
- Myelin sheath is a thick layer composed of lipoprotein, formed by Schwann cells in the Peripheral Nervous System (PNS)
- Axonal membrane is not covered with myelin sheath and exposed to Extra-Cellular Fluid (ECF)
- Myelin sheath increases the speed of conduction of nerve impulses
- Myelinated fibers allow current to flow at the Node of Ranvier, which produce Action Potentials
- Impulses jump from node to node in myelinated fibers, skipping over the myelinated portion of the axon, this is called saltatory conduction
- In the Central Nervous System (CNS), axons are myelinated by Oligodendrocytes, which do not regenerate.
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Description
Explore the essential components of neuron structure, including the cell body, dendrites, and axon. Learn about the myelination process, its role in nervous system function, and how it enhances nerve impulse conduction through saltatory conduction.
