nervous system 🧠
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Questions and Answers

What is the primary function of the central nervous system (CNS)?

  • To make voluntary actions automatic
  • To facilitate sensory reception only
  • To transmit nerve impulses to effectors
  • To regulate bodily functions and activities (correct)
  • Which type of neuron is responsible for transmitting nerve impulses from the sense organs to the CNS?

  • Sensory neurone (correct)
  • Relay neurone
  • Interneuron
  • Motor neurone
  • What type of action is primarily controlled by the spinal cord?

  • Reflex actions (correct)
  • Voluntary actions
  • Involuntary actions
  • Cognitive actions
  • What role do synapses play in the nervous system?

    <p>Junctions where chemical signals are transmitted between neurones</p> Signup and view all the answers

    Which of the following accurately describes the structure of a motor neurone?

    <p>Has an irregular-shaped cell body and one long nerve fibre</p> Signup and view all the answers

    How is a nerve impulse transmitted across a synapse?

    <p>By chemicals released by the neurones</p> Signup and view all the answers

    In the context of nerve impulses, what do 'effectors' refer to?

    <p>Muscles or glands that perform actions</p> Signup and view all the answers

    What occurs when a stimulus is detected by the receptors?

    <p>Nerve impulses are generated and transmitted to the CNS</p> Signup and view all the answers

    What does the term 'involuntary actions' refer to in the context of the nervous system?

    <p>Automatic actions not controlled consciously</p> Signup and view all the answers

    What is the primary function of a motor neurone in reflex actions?

    <p>To convey nerve impulses from the spinal cord to the effector muscles.</p> Signup and view all the answers

    Which type of reflex action is controlled by the spinal cord?

    <p>Spinal reflex</p> Signup and view all the answers

    What does the reflex arc represent?

    <p>The route nerve impulses take from receptor to effector.</p> Signup and view all the answers

    In the case of touching a hot object, which neurones transmit signals to the spinal cord?

    <p>Sensory neurones</p> Signup and view all the answers

    What is a key difference between the nervous control and endocrine control systems?

    <p>Responses from endocrine control are generally longer lasting.</p> Signup and view all the answers

    Which example illustrates a cranial reflex?

    <p>Rapidly blinking when a foreign object approaches the eye.</p> Signup and view all the answers

    Which statement accurately describes the nature of responses in nervous control?

    <p>Responses can be either voluntary or involuntary and are usually quick.</p> Signup and view all the answers

    Study Notes

    Sensitivity and Response

    • Sensitivity refers to the ability of organisms to react to stimuli in the environment.
    • A stimulus triggers a reaction known as a response.

    Role of the Nervous System

    • The human nervous system regulates bodily functions and interactions with the environment.
    • Voluntary actions are consciously controlled; involuntary actions operate without conscious control (e.g., heartbeat, breathing).

    Components of the Human Nervous System

    • Central Nervous System (CNS) includes the brain and spinal cord.
      • The spinal cord mainly handles automatic reflex actions.
      • The brain processes sensory information from touch, smell, and taste.
    • Peripheral Nervous System (PNS) comprises cranial and spinal nerves, as well as sensory organs.
      • Sensory organs actuate nerve impulses in response to stimuli.

    Neurones

    • Nervous tissue comprises nerve cells called neurons.
    • Each neuron consists of a cell body with a nucleus and nerve fibers (cytoplasmic strands).
      • Sensory Neurone: Transmits impulses from sense organs to the CNS, featuring a circular cell body and a long nerve fiber.
      • Relay Neurone: Relays impulses between sensory and motor neurons, typically located in the CNS with many short nerve fibers.
      • Motor Neurone: Sends impulses from the CNS to effectors, characterized by an irregular-shaped cell body and a long nerve fiber.

    Synapse

    • A synapse is the junction between two neurons.
    • Nerve impulse transmission across a synapse relies on chemicals, as impulses cannot cross directly.
    • Painkillers can block these synaptic spaces, preventing the transmission of nerve impulses.

    Nerve Impulse Pathways in the Spinal Cord

    • Sensation: Involves sensory and relay neurons; the brain interprets nerve impulses for sensations (e.g., feeling temperature).
      • Pathway: Receptor → Sensory Neurone → Relay Neurone → Brain.
    • Voluntary Action: Involves relay and motor neurons; initiated by conscious decision (e.g., raising a hand).
      • Pathway: Brain → Relay Neurone in spinal cord → Motor Neurone → Effector (muscle).

    Reflex Action

    • A reflex action is an automatic response to a stimulus without conscious thought.
    • Types of reflexes:
      • Cranial Reflexes: Controlled by the brain (e.g., blinking).
      • Spinal Reflexes: Governed by the spinal cord (e.g., withdrawing hand from heat).
    • Reflex Arc: The pathway for reflex actions, involving receptors, sensory neurons, relay neurons, motor neurons, and effectors.

    Endocrine vs. Nervous Control

    • Similarities: Both systems transmit messages to target organs in response to stimuli.
    • Differences:
      • Nervous control is localized; endocrine control can affect multiple organs via hormones.
      • Nervous control elicits quick responses; endocrine responses are slower.
      • Nervous responses can be voluntary, involuntary, short-lived; endocrine responses are usually involuntary and can be long-lived.

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