Questions and Answers
What are the two major anatomical subdivisions of the nervous system?
What does the CNS consist of?
Brain and Spinal Cord
What are the primary functions of the nervous system?
Providing sensation of the internal and external environments, integrating sensory information, regulating and controlling peripheral structures and systems
What are neurons responsible for?
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Where are voltage-gated sodium channels located in a neuron?
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How are neurons classified based on their structure?
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How are neurons classified based on their function?
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What are the two major cell populations of neural tissue?
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What types of glial cells are found in the CNS?
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What does the white matter of the CNS primarily consist of?
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What does depolarization of the membrane shift it toward?
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What is the resting membrane potential (RMP) of a typical neuron?
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If the resting membrane potential is -70 mV and the threshold is -60 mV, what happens at -62 mV?
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What does the membrane contain at the site of an action potential?
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If the resting membrane potential is -70 mV, what is a hyperpolarized membrane?
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What does a node along the axon represent?
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What happens as the diameter of the axon increases?
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What are the two most important factors that determine the rate of action potential conduction?
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What connects the presynaptic and postsynaptic membranes at an electrical synapse?
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What distinguishes chemical synapses from electric synapses?
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What does the effect of a neurotransmitter on the postsynaptic membrane depend on?
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What triggers exocytosis and the release of acetylcholine in the synaptic cleft?
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What is the normal stimulus for neurotransmitter release?
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What are inhibitory or hyperpolarizing CNS neurotransmitters?
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What is an excitatory postsynaptic potential (EPSP)?
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What is an inhibitory postsynaptic potential (IPSP)?
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What are the most important determinants of neural activity?
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Why do active neurons need ATP?
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What are sensory neurons responsible for?
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How do interneurons differ from sensory and motor neurons?
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What do efferent pathways consist of?
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What are graded potentials that develop in the postsynaptic membrane in response to a neurotransmitter?
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What is the addition of stimuli occurring in rapid succession called?
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Study Notes
Nervous System Subdivisions
- Two major subdivisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS).
- CNS comprises the brain and spinal cord.
Functions of the Nervous System
- Provides sensory information about internal and external environments.
- Integrates sensory information for processing.
- Regulates and controls peripheral structures and systems.
Neurons and Their Functions
- Neurons transfer and process information in the nervous system.
- Types of neurons based on structure: Anaxonic, Unipolar, Bipolar, Multipolar.
- Types of neurons based on function: Motor, Sensory, Association.
Glial Cells
- Two major cell populations in neural tissue: Neurons and Neuroglia.
- Glial cell types in CNS: Astrocytes, Oligodendrocytes, Microglia, Ependymal cells.
- White matter in CNS is dominated by oligodendrocytes.
Membrane Potentials
- Resting membrane potential (RMP) is typically -70 mV.
- Depolarization shifts membrane potential towards 0 mV.
- Hyperpolarization occurs when RMP is below -70 mV (e.g., -80 mV).
Action Potentials
- Action potential requires threshold of -60 mV; -62 mV will not generate one.
- Node along the axon indicates absence of myelin; larger axon diameter increases conduction speed.
- Rate of action potential conduction depends on myelin sheath presence and axon diameter.
Synapses
- Electrical synapses connect presynaptic and postsynaptic membranes at gap junctions.
- Chemical synapses utilize neurotransmitters for communication.
- Effect of neurotransmitter depends on receptor properties.
Neurotransmitter Release
- Acetylcholine release triggered by calcium ions in axoplasm.
- Arrival of an action potential depolarizes the synaptic knob, stimulating neurotransmitter release.
Postsynaptic Potentials
- Inhibitory neurotransmitters (e.g., Dopamine, Serotonin) induce hyperpolarization (IPSP).
- Excitatory postsynaptic potential (EPSP) results from depolarization by neurotransmitter arrival.
- Neural activity is primarily determined by EPSP-IPSP interactions.
Energy Requirements of Neurons
- Active neurons require ATP for neurotransmitter synthesis, release, recycling, recovering from action potentials, and axoplasmic flow.
Sensory and Interneurons
- Sensory neurons send impulses to the CNS.
- Interneurons are located exclusively within the CNS (brain and spinal cord).
- Efferent pathways transport impulses away from the CNS.
Summation
- Graded potentials from postsynaptic membranes in response to neurotransmitters are termed Postsynaptic Potentials.
- Temporal summation involves the rapid succession of stimuli.
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Description
Explore the major subdivisions of the nervous system, including the Central and Peripheral Nervous Systems. Understand the functions of neurons, types of glial cells, and membrane potentials. This quiz covers crucial concepts for anyone studying the nervous system.