Nervous coordination

2.4.3 Process

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Nervous coordination

  1. The brain

    1. The brain controls complex behaviours
    2. It is made of billions of interconnected neurons
    3. Different regions of the brain perform different functions
    4. The cerebral cortex is associated with consciousness, intelligence, memory and language
    5. The cerebellum is associated mainly with the coordination of muscular activity
    6. The medulla is associated with unconscious activities, such as heartbeat and breathing
    7. Scientists have been able to map the regions of the brain to particular functions by studying patients with brain damage, electrically stimulating different parts of the brain and using MRI scanning techniques

  2. Nervous coordination

    1. The nervous system enables humans to react to their surrounding and coordinate behaviour
    2. Information from receptors passes along neurons as impulses and to the central nervous system, either the brain or the spinal cord
    3. The brain coordinates the response and an impulse is sent to an effector, such as muscles or glands
    4. A nervous response can normally be analysed in terms of: stimulus → receptor → coordinator → effector → response

  3. Reflex actions

    1. Reflex actions are automatic and rapid
    2. They often involve sensory, relay and motor neurons

    3. Mechanism

      1. Impulses from a receptor pass along a sensory neuron to the central nervous system
      2. At the synapse between a sensory and a relay neuron in the central nervous system, a neurotransmitter is released that causes an impulse to be sent along the relay neuron
      3. At the synapse between the relay and a motor neuron in the central nervous system, a neurotransmitter is released that causes an impulse to be sent along the motor neuron
      4. The effector is either a muscle or a gland, which responds by contracting or secreting chemical substances respectively