Neuron Structure Quiz
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Questions and Answers

What role do carrier vesicles play in neurotransmitter transport?

  • They store neurotransmitters until they're needed.
  • They facilitate the docking of vesicles at the synapse.
  • They transport neurotransmitters across the synaptic cleft.
  • They contain membrane transporter proteins moved along microtubules. (correct)
  • Which neurotransmitter is classified as a monoamine and can be inhibitory or excitatory?

  • Dopamine (correct)
  • Acetylcholine
  • Glutamate
  • GABA
  • What is the function of the hippocampus within the limbic system?

  • Controlling emotional responses to fear
  • Regulating sleep and alertness
  • Processing auditory signals
  • Processing long term memory and spatial navigation (correct)
  • What is the primary function of dendrites in a neuron?

    <p>Conduct impulses towards the cell</p> Signup and view all the answers

    Which lobe of the cerebrum is primarily responsible for processing visual information?

    <p>Occipital lobe</p> Signup and view all the answers

    What structure connects the left and right hemispheres of the brain?

    <p>Corpus callosum</p> Signup and view all the answers

    What is the role of oligodendrocytes in the central nervous system?

    <p>Create myelin sheaths around axons</p> Signup and view all the answers

    Which brain structure is involved in regulating emotional responses and is associated with fear?

    <p>Amygdala</p> Signup and view all the answers

    How does myelin affect nerve conduction speed?

    <p>Increases speed by providing insulation</p> Signup and view all the answers

    Which structure in a neuron is responsible for sending messages as electrical impulses?

    <p>Axon</p> Signup and view all the answers

    What type of neurotransmitter is acetylcholine classified as?

    <p>Amino acid</p> Signup and view all the answers

    Which part of the brainstem is responsible for controlling involuntary functions like breathing?

    <p>Medulla</p> Signup and view all the answers

    The accumulation of voltage-gated sodium channels at the nodes of Ranvier is a result of which process?

    <p>Axon myelination</p> Signup and view all the answers

    What role does the thalamus play in the brain?

    <p>Acting as a relay center for sensory signals</p> Signup and view all the answers

    What percentage of myelin is comprised of lipid content?

    <p>70%</p> Signup and view all the answers

    Defects in myelination and myelin structure can occur due to exposure to which of the following substances?

    <p>Alcohol</p> Signup and view all the answers

    Which lobe of the cerebrum is involved with language comprehension and memory?

    <p>Temporal lobe</p> Signup and view all the answers

    Which part of a neuron contains the nucleus and cytoplasm?

    <p>Cell body</p> Signup and view all the answers

    What is the primary function of the hypothalamus?

    <p>Maintaining homeostatic balance</p> Signup and view all the answers

    What is the main role of neuropeptides like orexin in the central nervous system?

    <p>Controlling sleep-wake cycles and energy balance</p> Signup and view all the answers

    What best describes the function of excitatory neuron 1 in the context of neuronal interaction?

    <p>It activates inhibitory neuron 2, silencing neuron 3.</p> Signup and view all the answers

    Which area of the cerebrum contains sensory areas for reading and writing?

    <p>Parietal lobe</p> Signup and view all the answers

    What is the primary cause of the dysfunction in multiple sclerosis (MS)?

    <p>Immune mediated destruction of myelin</p> Signup and view all the answers

    Which type of neuron is characterized by having a single axon and a single dendrite?

    <p>Bipolar neuron</p> Signup and view all the answers

    Which ion channel opens at -55mV and is crucial for initiating an action potential?

    <p>Voltage-gated sodium channel</p> Signup and view all the answers

    What is the resting membrane potential of a neuron?

    <p>-70mV</p> Signup and view all the answers

    What role do high-dose corticosteroids play in the treatment of multiple sclerosis?

    <p>They dampen inflammation</p> Signup and view all the answers

    What is the outcome when sodium channels at the axon hillock are sensitized to -55mV?

    <p>Depolarization of the neuron</p> Signup and view all the answers

    What type of neuron is found predominantly in sensory ganglia of cranial and spinal nerves?

    <p>Pseudounipolar neurons</p> Signup and view all the answers

    Calcium channels open at the presynaptic terminal during which phase of synaptic transmission?

    <p>Depolarization</p> Signup and view all the answers

    Which type of receptor responds to neurotransmitters by indirectly opening ion channels?

    <p>Metabotropic receptor</p> Signup and view all the answers

    What is the role of Na+/K+ transporters in neurons?

    <p>Maintains resting membrane potential</p> Signup and view all the answers

    What occurs when ligand-gated ion channels open in response to neurotransmitters?

    <p>Increase in membrane potential</p> Signup and view all the answers

    What is the common feature of multipolar neurons?

    <p>Many dendrites originating from different regions</p> Signup and view all the answers

    What is the function of SNARE proteins in synaptic transmission?

    <p>Facilitate vesicle fusion with the membrane</p> Signup and view all the answers

    During which phase does repolarization occur in an action potential?

    <p>After depolarization peaks</p> Signup and view all the answers

    What is the role of the lateral nucleus (LA) in the amygdala?

    <p>It serves as the sensory interface and a key site of plasticity.</p> Signup and view all the answers

    What type of information do the medial entorhinal cortex (MEC) and lateral entorhinal cortex (LEC) relay to the hippocampus?

    <p>Both spatial and non-spatial information.</p> Signup and view all the answers

    Which drug class is commonly used to treat anxiety disorders by enhancing GABA-mediated synaptic inhibition?

    <p>Benzodiazepines</p> Signup and view all the answers

    What is a common early symptom of Alzheimer's disease?

    <p>Loss of sense of smell</p> Signup and view all the answers

    How does the hypothalamus regulate body temperature?

    <p>By stimulating heat production or cooling mechanisms.</p> Signup and view all the answers

    What vulnerability is associated with the dysfunction of cholinergic neurons in the context of Alzheimer's disease?

    <p>Cognitive dysfunction and memory impairment.</p> Signup and view all the answers

    What function does the amygdala primarily serve in relation to emotional responses?

    <p>Maintains balance between excitatory and inhibitory signals.</p> Signup and view all the answers

    What is the primary role of serotonin in relation to the amygdala?

    <p>Increases glutamatergic activity.</p> Signup and view all the answers

    What result is generally associated with damage to the hypothalamus?

    <p>Appetite regulation and temperature disorders.</p> Signup and view all the answers

    In the context of fear conditioning, what role does the auditory thalamic input have?

    <p>It leads to fear memory formation.</p> Signup and view all the answers

    What characterizes the projection pathways of the hippocampus?

    <p>They follow a specific circuit through different regions.</p> Signup and view all the answers

    What is a symptom of generalized anxiety disorder?

    <p>Excessive and uncontrollable worry.</p> Signup and view all the answers

    Which treatment is effective for Alzheimer's disease by blocking the breakdown of acetylcholine?

    <p>Cholinesterase inhibitors.</p> Signup and view all the answers

    Study Notes

    Neuron Structure

    • The basic unit of the nervous system is the neuron (nerve cell)
    • Neurons consist of a cell body, dendrites, and an axon
    • The cell body contains the nucleus and cytoplasm, responsible for transcription and translation
    • Dendrites are branched extensions of the cell body, conducting impulses towards the cell body
    • The axon is an elongated extension of the cell body, sending messages as electrical impulses

    Neuron Structure - Axon Myelination

    • Myelin is a fatty substance that insulates axons, increasing the speed of nerve conduction
    • Myelin sheaths are created by oligodendrocytes in the central nervous system
    • Myelination results in the accumulation of voltage-gated sodium channels at the nodes of Ranvier

    Neuron Structure - Common Structures

    • Multipolar neurons have multiple dendrites extending from different regions of the cell body, the most common type of neuron in the CNS
    • Bipolar neurons have two processes: one axon and one dendrite, found in sensory organs such as the retina and olfactory epithelium
    • Pseudounipolar neurons have two processes that fuse into one short axon, found in sensory ganglia of cranial and spinal nerves

    Neuron Function - Synaptic Transmission

    • Communication between neurons occurs at synapses
    • Synaptic transmission involves the release of neurotransmitters from the presynaptic neuron, which bind to receptors on the postsynaptic neuron
    • Ion channels and neurotransmitter receptors control synaptic transmission
    • Voltage-gated ion channels directly open ion channels in response to changes in membrane potential
    • Ligand-gated ion channels directly open in response to neurotransmitters
    • Metabotropic receptors indirectly open ion channels in response to neurotransmitters

    Synaptic Transmission: Action Potential Generation

    • Resting membrane potential is typically -70mV
    • Binding of neurotransmitters to receptors causes changes in ion concentration, resulting in changes in membrane potential
    • When the membrane potential reaches -55mV, it triggers the opening of voltage-gated sodium channels
    • Depolarization is the process of the membrane potential becoming more positive, while repolarization is the process of the membrane potential returning to its resting value
    • Depolarization of the presynaptic terminal opens calcium channels, triggering the release of neurotransmitters

    Ion Channels

    • Voltage-gated sodium channels open at -55mV and inactivate at +40mV
    • Voltage-gated potassium channels open slowly and cause hyperpolarization, returning the membrane potential to its resting value
    • The sodium-potassium pump actively transports ions to maintain resting levels

    Vesicle Docking and Neurotransmitter Release

    • Calcium binds to SNARE proteins, triggering the fusion of vesicles with the presynaptic membrane
    • Fusion releases neurotransmitters into the synapse

    Neurotransmitters

    • Dopamine, norepinephrine, serotonin, and acetylcholine are monoamines
    • GABA, glutamate, and glycine are amino acids
    • Orexin is a neuropeptide

    Neuron Response

    • Excitatory neurons activate other neurons, increasing their likelihood of firing
    • Inhibitory neurons suppress the activity of other neurons
    • Neuronal networks can have complex interactions, with multiple excitatory and inhibitory connections

    The Central Nervous System

    • The CNS is made up of the brain and spinal cord

    Brain Anatomy

    • The cerebrum is the largest part of the brain, responsible for higher-level functions such as perception, cognition, and memory
    • The brain stem connects the brain to the spinal cord, responsible for regulating basic functions such as breathing and heart rate
    • The limbic system is involved in emotional and behavioral responses

    Limbic System

    • The amygdala is involved in processing fear and other emotions
    • The hippocampus is involved in long-term memory and spatial navigation
    • The thalamus acts as a relay center for sensory and motor signals
    • The hypothalamus coordinates hormonal and behavioral rhythms and homeostatic mechanisms

    Brain Stem

    • The midbrain is involved in auditory and visual processing, arousal, and consciousness
    • The pons carries signals that control basic functions such as sleep
    • The medulla controls involuntary functions such as breathing and heart rate

    Cerebral Cortex: Neocortex

    • The cerebral cortex is the outermost layer of the cerebrum, responsible for higher-level cognitive functions
    • The neocortex is made up of six layers, each with different functions

    The Amygdala

    • The amygdala is a key structure involved in fear conditioning and emotional responses to aversive stimuli
    • The central nucleus of the amygdala is the output region of the amygdala
    • The lateral nucleus of the amygdala receives sensory input and is involved in fear memory formation
    • Dysfunction of the amygdala can lead to anxiety disorders and other emotional disorders

    The Hippocampus

    • The hippocampus is crucial for memory formation, particularly for spatial navigation
    • The entorhinal cortex is the main input and output structure of the hippocampal formation
    • The hippocampus contains cholinergic neurons, which are important for normal memory function
    • The hippocampus is affected in Alzheimer's disease, leading to memory impairment and cognitive decline

    The Thalamus and Brain Stem

    • The thalamus plays a vital role in sleep-wake regulation and arousal
    • The brain stem connects the brain to the spinal cord and is also involved in regulating sleep and arousal

    The Hypothalamus

    • The hypothalamus links the nervous system to the endocrine system via the pituitary gland
    • The hypothalamus produces and releases neurohormones
    • The hypothalamus is involved in regulating temperature, appetite, and sexual behavior
    • Dysfunction of the hypothalamus can cause appetite, temperature, and sleep disorders

    Summary

    • The text provides a comprehensive overview of the structure and function of neurons, the main regions of the brain (including the cerebrum, limbic system, and brain stem), and the role of key neurotransmitters
    • The text also discusses the mechanisms of synaptic transmission and the impact of neuronal dysfunction on various brain functions and disorders

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    Test your knowledge on the structure and function of neurons. This quiz covers the basic components of neurons, myelination, and different types of neurons. Perfect for students studying biology or neuroscience!

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