Questions and Answers
Which part of a neuron is primarily responsible for receiving incoming signals?
What type of glial cell is responsible for creating the myelin sheath in the central nervous system?
Which neurotransmitter is primarily inhibitory and plays a significant role in reducing neuronal excitability?
What mechanism allows for rapid conduction of action potentials along myelinated axons?
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Which type of neuron is primarily involved in reflex actions and connects sensory and motor pathways?
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What is the primary role of astrocytes in the nervous system?
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In terms of neuron classification by function, which type primarily carries signals toward the central nervous system?
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How do changes in synaptic connection sensitivity impact neuronal processing?
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Which type of neuron is classified as motor?
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What term is used to describe a group of neuronal cell bodies?
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Which of the following neurotransmitter groups influences excitation of a neuron?
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At what membrane potential is an action potential typically triggered?
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What type of membrane potential remains when a neuron is at rest?
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Which type of neuron releases GABA and is inhibitory?
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What term describes the graded potentials that occur at sensory receptors?
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Which classification system of neurons considers axon diameter and myelin status?
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What type of ion channels are always open and allow potassium ions (K+) to flow?
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What is the effect of a depolarizing stimulus on the membrane potential?
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What role do voltage gated channels play in action potentials?
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Which of the following factors can increase the conduction velocity of action potentials?
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What term describes the conduction of action potentials across myelinated axons?
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What is the primary effect of auto-immune disorders like Myasthenia Gravis on the nervous system?
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What triggers the opening of voltage gated channels in neurons?
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What happens to the membrane potential during hyperpolarization?
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What triggers the release of neurotransmitters from vesicles?
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Which neurotransmitter is primarily associated with excitatory postsynaptic potentials (EPSP)?
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How does GABA influence neuronal activity?
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What is the result of spatial summation of EPSPs and IPSPs if they balance each other out?
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During what condition will a neuron fire an action potential?
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Which of the following best describes inhibitory postsynaptic potentials (IPSP)?
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What determines the intensity of a stimulus in relation to generator potentials?
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Which neurotransmitter is primarily found in the peripheral nervous system (PNS)?
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What is one of the primary functions of microglia?
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Which of the following statements about glial cells is true?
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What type of tumor is a glioblastoma classified as?
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How do glial cells assist in neuron health?
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What effect do primary brain tumors typically have on intracranial pressure?
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What substance do microglia release after a stroke or trauma that can be neurotoxic?
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Which of the following glial tumors is associated with the Schwann cells?
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What is a characteristic of primary brain tumors regarding their growth?
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Study Notes
Neurons and Their Components
- Neurons serve as the primary information processors in the nervous system.
- Key components include cell body, dendrites, and axons.
- Myelin sheaths increase conduction speed along axons; nodes of Ranvier facilitate saltatory conduction.
- Neurons classified by shape: multipolar, bipolar, unipolar.
- Neurons classified by function: motor (efferent), sensory (afferent), interneurons.
Neurophysiology Basics
- Membrane potentials include resting (-70 mV), generator (local), and action potentials.
- Action potentials occur when a threshold (-55 mV) is reached and propagate along the axon.
- Generator potentials are graded responses that can be depolarizing (excitatory) or hyperpolarizing (inhibitory).
Synaptic Transmission
- Synapses consist of presynaptic and postsynaptic membranes.
- Neurotransmitters like glutamate and acetylcholine facilitate excitatory postsynaptic potentials (EPSPs).
- GABA is the main inhibitory neurotransmitter, generating inhibitory postsynaptic potentials (IPSPs).
- Combined effects of EPSPs and IPSPs determine whether an action potential will be fired.
Glial Cells and Their Functions
- Glial cells outnumber neurons and support brain function.
- Types of glia include microglia, oligodendrocytes, Schwann cells, and astrocytes.
- Glia help maintain homeostasis, provide nutrients, respond to injury, and form scars in damaged areas.
Ion Channels and Membrane Potentials
- Ion gradients create membrane potentials; major ions include sodium (Na+), potassium (K+), calcium (Ca2+), and chloride (Cl-).
- Types of ion channels include leakage channels (always open) and gated channels (open in response to stimuli).
- Changes in membrane potential can occur due to opening/closing of ion channels, affecting neuronal excitability.
Action Potential Mechanism
- Depolarization triggers rapid influx of sodium ions, followed by a rise in membrane potential to +40 mV.
- Action potentials are "all or nothing" events, with conduction velocity influenced by axon diameter and myelination.
- Myelinated axons conduct action potentials faster via saltatory conduction.
Clinical Relevance
- Some disorders, such as Myasthenia Gravis and Multiple Sclerosis, affect synaptic transmission and axonal propagation.
- Gliomas, including astrocytomas and oligodendrogliomas, are examples of brain tumors arising from glial cells.
- Symptoms of these tumors depend on location, size, and growth rate.
Summary of Key Concepts
- Neurons are vital for information processing; glial cells offer critical support.
- Neurotransmitter activity defines synaptic transmission, influencing neuronal behavior.
- Understanding membrane potentials and ion channels is crucial for grasping neuronal excitability and communication.
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Description
This quiz focuses on the fundamentals of neurophysiology, including the components of neurons, mechanisms of activation, and synaptic transmission. Additionally, it explores the role of glial cells in supporting neuronal functions. Test your knowledge on the basic principles that underpin how neurons process information.
