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Reflex Arcs in Anatomy & Physiology

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  • What is a reflex?

    A reflex is a rapid, involuntary response to a stimulus.
  • What is the function of an interneuron in a reflex arc?

    An interneuron transmits impulses between motor and sensory neurons.
  • How many steps are in a reflex arc?

    A reflex arc has 5 steps.
  • What is the first step in a reflex arc?

    The receptor detects a stimulus.
  • What does the sensory neuron do in a reflex arc?

    The sensory neuron transmits impulses from the receptor to the central nervous system.
  • What is the role of the integration center in a reflex arc?

    The integration center consists of interneurons (or a single synapse) between sensory and motor neurons.
  • What does the motor neuron do in a reflex arc?

    The motor neuron conducts impulses from the integration center to the effector.
  • What is the effector in a reflex arc?

    The effector is a gland or muscle fiber that responds to the stimulus by secreting or contracting.
  • What are the two types of reflex development?

    Innate reflexes are genetically programmed during natural development; acquired reflexes are complex, learned motor patterns.
  • What are the two response types of reflexes?

    Somatic reflexes cause rapid, involuntary skeletal muscle responses; autonomic (visceral) reflexes control non-skeletal organs.
  • What distinguishes monosynaptic from polysynaptic reflexes?

    Monosynaptic reflexes have one synapse during integration; polysynaptic reflexes have multiple synapses.
  • What is the purpose of the stretch reflex?

    The stretch reflex prevents muscle strain and tear injuries.
  • What initiates the stretch reflex?

    Muscle spindles initiate the stretch reflex in response to being stretched.
  • What happens to the muscle during the stretch reflex?

    The stretched muscle contracts.
  • What is reciprocal inhibition in the stretch reflex?

    Neurons inhibit the antagonistic muscle during the stretch reflex, allowing smooth movement.
  • What is the purpose of the tendon reflex?

    The tendon reflex prevents tendon injury by responding to excessive tension.
  • What initiates the tendon reflex?

    Golgi tendon organs initiate the tendon reflex in response to tendon tension.
  • What happens to the muscle during the tendon reflex?

    The muscle relaxes to prevent damage.
  • What is reciprocal activation in the tendon reflex?

    Neurons activate the antagonistic muscle during the tendon reflex to balance muscle activity.
  • What is the flexor (withdrawal) reflex?

    A rapid withdrawal of a body part from a painful or harmful stimulus.
  • What side of the body does the flexor reflex affect?

    The flexor reflex is ipsilateral; motor activity occurs on the same side as the stimulus.
  • What is the crossed-extensor reflex?

    It causes extension of the opposite limb to maintain balance during the flexor reflex.
  • What side of the body does the crossed-extensor reflex affect?

    The crossed-extensor reflex is contralateral; motor activity occurs on the opposite side of the stimulus.