Nervous System part 1
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Questions and Answers

What is the primary function of dendrites in neurons?

  • To form myelin sheaths around nerve fibers
  • To transmit impulses away from the cell body
  • To provide structural support to the neuron
  • To receive information and pass it to the cell body (correct)

    • Which type of glial cell is primarily responsible for forming and maintaining myelin in the central nervous system?

  • Oligodendrocytes (correct)
  • Microglia
  • Ependymal cells
  • Astrocytes

    • What substance is primarily responsible for crossing the blood-brain barrier quickly?

  • Large molecules
  • Inorganic ions
  • Many drugs
  • Oxygen and glucose (correct)

    • What role do synaptic vesicles play in neurotransmission?

    <p>To store neurotransmitters</p> Signup and view all the answers

    What is the main characteristic of astrocytes in the central nervous system?

    <p>They provide a structural framework and support to neurons</p> Signup and view all the answers

    Which neurotransmitter is specifically mentioned in the content in relation to synapses?

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

    What characteristic defines the irritability of neurons?

    <p>The ability to initiate impulses in response to stimuli</p> Signup and view all the answers

    What do microglia do in response to inflammation and cell destruction?

    <p>Increase in number and become phagocytic</p> Signup and view all the answers

    What is the primary function of Schwann cells in the peripheral nervous system?

    <p>To provide myelin insulation to axons.</p> Signup and view all the answers

    Which of the following correctly describes the role of the nodes of Ranvier?

    <p>They assist in the rapid transmission of action potentials.</p> Signup and view all the answers

    Which division of the nervous system responds to external stimuli?

    <p>Peripheral nervous system.</p> Signup and view all the answers

    What best describes the function of the cell body in a neuron?

    <p>It houses the nucleus and organelles.</p> Signup and view all the answers

    Which component of the nervous system is primarily responsible for involuntary responses?

    <p>Autonomic nervous system.</p> Signup and view all the answers

    What are action potentials primarily generated by?

    <p>Changes in ion permeability of the neuron's membrane.</p> Signup and view all the answers

    Which of these characteristics is NOT associated with myelinated neurons?

    <p>Slower transmission of action potentials.</p> Signup and view all the answers

    Which of the following describes the central nervous system?

    <p>Consists of the brain and spinal cord.</p> Signup and view all the answers

    Study Notes

    Nervous System Overview

    • The nervous system detects and responds to internal and external changes in the body.
    • It works alongside the endocrine system to control body function and maintain homeostasis.
    • The nervous system provides immediate responses, while endocrine activity is slower and prolonged.

    Nervous System Divisions

    • The nervous system is divided into the central and peripheral systems:
      • Central Nervous System (CNS): Brain and spinal cord
      • Peripheral Nervous System (PNS): All other nerves

    Peripheral Nervous System Divisions

    • The PNS is further divided into sensory and motor divisions:
      • Sensory Division: Carries sensory information from the body to the CNS
      • Motor Division: Carries motor commands from the CNS to the body
        • Somatic Nervous System: Voluntary control of skeletal muscles
        • Autonomic Nervous System: Involuntary control of internal organ functions
          • Sympathetic Nervous System: "Fight or flight" response
          • Parasympathetic Nervous System: "Rest and digest" response

    Nervous Tissue: Cells

    • Nervous tissue consists of three main cell types:
      • Neurones: Specialized cells that transmit nerve impulses
      • Schwann Cells: Supporting cells that form the myelin sheath around axons in the PNS
      • Neuroglial/Glial Cells: Supporting cells of the CNS

    Neurone Structure

    • Neurones have distinct structural features:
      • Cell Body: Contains the nucleus and other organelles
      • Axon: Long, slender projection that conducts nerve impulses away from the cell body
      • Schwann Cells: Wrap around axons to form the myelin sheath
      • Nodes of Ranvier: Gaps between Schwann cells, facilitating rapid impulse transmission
      • Dendrites: Short, branched projections that receive nerve impulses from other neurones
      • Synaptic End Bulb: Terminal of the axon, containing neurotransmitters

    Neurone Properties

    • Neurones exhibit two key properties:
      • Irritability: Ability to initiate nerve impulses in response to stimuli
      • Conductivity: Ability to transmit nerve impulses

    Neuroglial (Glial) Cells

    • Neuroglial cells are non-excitable cells that support neurones in the CNS.
    • They continue to replicate throughout life.
    • There are three main types:
      • Microglia: Phagocytic cells that remove debris and pathogens
      • Astrocytes: Star-shaped cells that provide structural support and regulate nutrient and waste exchange
      • Oligodendrocytes: Form and maintain myelin sheaths around axons in the CNS

    Blood-Brain Barrier

    • The blood-brain barrier is a selectively permeable membrane that protects the brain from toxic substances and blood fluctuations.
    • It allows the passage of essential substances like oxygen, carbon dioxide, glucose, and lipid-soluble molecules.

    Synaptic End Bulbs and Neurotransmission

    • Synaptic end bulbs are specialized structures at the end of axons, responsible for transmitting nerve impulses to other neurones or effector cells.
    • They contain synaptic vesicles that store neurotransmitters, such as acetylcholine and noradrenaline.
    • Neurotransmission occurs through the release of neurotransmitters at the synapse.

    Synapse

    • The synapse is the junction between two neurones or a neurone and an effector cell.
    • It consists of:
      • Pre-synaptic Neurone: Releases neurotransmitters
      • Pre-synaptic Knob: Terminal of the axon containing synaptic vesicles
      • Neurotransmitters: Chemical messengers released at the synapse
      • Post-synaptic Knob: Receptor sites on the receiving cell
      • Post-synaptic Neurone: Receives the neurotransmitter signal

    Neuro-transmission

    • Neurotransmission involves a series of steps:
      • Action Potential Arrival: Nerve impulse reaches the pre-synaptic knob
      • Calcium Influx: Calcium ions enter the pre-synaptic knob
      • Neurotransmitter Release: Synaptic vesicles fuse with the pre-synaptic membrane and release neurotransmitters
      • Neurotransmitter Binding: Neurotransmitters bind to receptors on the post-synaptic membrane
      • Post-synaptic Potential: Binding triggers a change in the post-synaptic cell's membrane potential
      • Neurotransmitter Removal: Neurotransmitters are removed from the synapse, either by re-uptake into the pre-synaptic neurone or by enzymatic breakdown.

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    Description

    Anatomy & Physiology of Nervous Tissue

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