Peripheral Nervous System Overview
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Questions and Answers

Which branch of the autonomic nervous system is responsible for the 'fight or flight' response?

  • Sympathetic branch (correct)
  • Parasympathetic branch
  • Somatic branch
  • Central nervous system
  • What type of muscles does the somatic nervous system primarily control?

  • Striated muscles (correct)
  • Smooth muscles
  • Cardiac muscles
  • Involuntary muscles
  • What role do neuroglia play in the nervous system?

  • Control muscle contractions
  • Transmit nerve impulses
  • Promote synapse formation
  • Regulate ionic concentration (correct)
  • Which of the following is NOT a characteristic of neuroglia?

    <p>They can generate nerve impulses</p> Signup and view all the answers

    What is the primary function of the parasympathetic branch of the autonomic nervous system?

    <p>Maintain everyday activities</p> Signup and view all the answers

    What is the primary role of astrocytes in the central nervous system?

    <p>Nourish neurons and maintain environment</p> Signup and view all the answers

    What distinguishes protoplasmic astrocytes from fibrous astrocytes?

    <p>Protoplasmic astrocytes have numerous branching processes</p> Signup and view all the answers

    What is a characteristic feature of oligodendroglia in the central nervous system?

    <p>They can myelinate multiple axons</p> Signup and view all the answers

    Which cells are responsible for producing myelin in the peripheral nervous system?

    <p>Schwann cells</p> Signup and view all the answers

    What is the primary function of microglia in the central nervous system?

    <p>Respond to injury and destroy bacteria</p> Signup and view all the answers

    What is the role of satellite cells in the peripheral nervous system?

    <p>Surround and support neurons</p> Signup and view all the answers

    What are the uncoated areas on axons called that aid in signal propagation?

    <p>Nodes of Ranvier</p> Signup and view all the answers

    What type of cells line the cavities of the brain and spinal cord?

    <p>Ependymal cells</p> Signup and view all the answers

    What is the primary function of ependymal cells in the central nervous system?

    <p>To form and circulate cerebrospinal fluid</p> Signup and view all the answers

    Which type of cell is responsible for the formation of the myelin sheath in the central nervous system?

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

    What characterizes the function of microglia in the central nervous system?

    <p>They help protect neurons by engulfing invaders.</p> Signup and view all the answers

    What does the term 'efferent' refer to in the context of neural processes?

    <p>Motor communication from brain to body</p> Signup and view all the answers

    In the context of neuronal firing, what occurs when an impulse is created?

    <p>The permeability of the cell membrane changes.</p> Signup and view all the answers

    How is signaling between neurons primarily characterized?

    <p>Electrochemical interaction.</p> Signup and view all the answers

    What happens to neurons affected by Alzheimer's dementia?

    <p>They become entangled and fail to transmit impulses.</p> Signup and view all the answers

    Which of the following best describes the concept of a gyrus?

    <p>The raised portion of the brain.</p> Signup and view all the answers

    What primarily maintains the resting potential of a neuron?

    <p>A large concentration of negatively charged chloride ions</p> Signup and view all the answers

    What happens when a neuron is stimulated by a weak impulse?

    <p>There is a slight change in electrical charge, but no action occurs</p> Signup and view all the answers

    What is synaptic transmission primarily responsible for?

    <p>Transmitting signals between neurons, muscles, or glands</p> Signup and view all the answers

    What is the role of excitatory postsynaptic potential (EPSP)?

    <p>To increase the likelihood of action potential generation</p> Signup and view all the answers

    Which type of synapse connects an axon directly to another axon?

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

    What effect do inhibitory postsynaptic potentials (IPSPs) have on a neuron's membrane potential?

    <p>They hyperpolarize the neuron, reducing excitability</p> Signup and view all the answers

    What integral role does the semi-permeable membrane play in a neuron's function?

    <p>It maintains ion imbalances and regulates ion flow</p> Signup and view all the answers

    What is the potential outcome if the stimulus to a neuron is strong enough?

    <p>An action potential will be triggered</p> Signup and view all the answers

    What is the primary function of the sodium-potassium pump in a neuron?

    <p>To maintain the resting state of the cell</p> Signup and view all the answers

    What characterizes the intracellular fluid in a neuron?

    <p>It contains large amounts of potassium</p> Signup and view all the answers

    Which of the following accurately describes the polarization of a neuron?

    <p>Negative inside and positive outside</p> Signup and view all the answers

    During the resting state of a neuron, what is the typical membrane potential measurement?

    <p>-50 to -70 microvolts</p> Signup and view all the answers

    What is the effect of concentration gradients and charge gradients on neuronal function?

    <p>They assist in the transport of ions necessary for action potentials.</p> Signup and view all the answers

    What will happen if the sodium-potassium pump fails to function properly?

    <p>Neurons will be unable to fire action potentials.</p> Signup and view all the answers

    Which ions are in higher concentration outside a neuron compared to the inside?

    <p>Chloride and Sodium</p> Signup and view all the answers

    What triggers the action potential in a neuron?

    <p>A change in membrane voltage</p> Signup and view all the answers

    Study Notes

    Peripheral Nervous System (PNS)

    • PNS is divided into two main systems: Somatic and Autonomic.
    • Somatic System: Controls voluntary muscles (striated).
    • Autonomic System: Controls involuntary muscles (smooth), further divided into:
      • Sympathetic Branch: Triggers "fight or flight" response; increases heart rate, dilates pupils, alters saliva production during arousal events (fear, drugs).
      • Parasympathetic Branch: Responsible for maintenance of routine activities and calming the body post-arousal.

    Neurons and Neuroglia

    • Neurons are supported by non-excitable cells called neuroglia, which outnumber neurons by 5-10 times.
    • Neuroglia regulate ionic concentration in the extracellular fluid and do not generate nerve impulses.

    Types of Neuroglia

    • Astrocytes:
      • Most common in CNS; nourish neurons and support their structures.
      • Part of the blood-brain barrier, restricting blood substance movement.
      • Types include:
        • Protoplasmic: Found in gray matter.
        • Fibrous: Found in white matter.
    • Oligodendroglia: Myelinate multiple axons in the CNS.
    • Schwann Cells: Myelinate single axons in the PNS.
    • Microglia: Act as immune defenders, removing pathogens through phagocytosis.
    • Ependymal Cells: Line CNS cavities and regulate cerebrospinal fluid (CSF) flow.

    Neuronal Communication

    • Neurons communicate through electrical and chemical processes involving action potentials.
    • Efferent signals are motor (top-down), and afferent signals are sensory (bottom-up).
    • Synaptic transmission involves neurotransmitters facilitating communication across synapses.

    Neuronal Firing Dynamics

    • Neurons are constantly active, firing when impulses trigger membrane permeability changes.
    • Resting potential ranges from -50 to -70 mV, maintained by the sodium-potassium pump.
    • Action potential occurs when a neuron is sufficiently stimulated, resulting in an electrical impulse that propagates along the axon.

    Synapse Functionality

    • Synapses connect neurons for signal transmission, allowing communication with muscles or glands.
    • Neurotransmitters mediate transmission; they may excite (EPSP) or inhibit (IPSP) subsequent action potentials.
    • Different synapse types:
      • Dendrodendritic: Dendrite to dendrite.
      • Axodendritic: Axon to dendrite (most common).
      • Axosomatic: Axon to cell body.
      • Axoaxonic: Axon to axon.

    Electrical Activity of Neurons

    • Changes in ionic concentrations create a gradient critical for neuronal activity.
    • Intracellular fluid contains high potassium levels, while extracellular fluid is rich in sodium.
    • Proper ion balance is essential for maintaining resting potential and during action potentials.

    Neurological Disorders

    • Disorders often stem from dysfunction in neuronal cellular and molecular activities.
    • For instance, Alzheimer’s dementia is linked to neuronal entanglement leading to impaired synaptic transmission.

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    Description

    Explore the Peripheral Nervous System (PNS) with a focus on its main divisions: the Somatic and Autonomic systems. Understand how each system functions, the role of neurons, and the types of neuroglia that support neuronal activities. This quiz will test your knowledge of these essential concepts in neuroscience.

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