coordination and response part one

• Coordination and response


  Organisms require proper coordination between various organs and systems to work together to keep them alive
• Nervous system


  Plays a key role in the coordination and regulation of body functions
• Nervous system function


  1. Receives and processes information from the environment and from within the body

  2. Generates appropriate responses to maintain homeostasis
• Neuron


  Nerve cell
• Nerve


  Bundle of neurons
• Components of the mammalian nervous system

  • Central nervous system (brain and spinal cord)
  • Peripheral nervous system (nerves outside brain and spinal cord)
• Types of neurons


  • Sensory neurons
  • Relay neurons
  • Motor neurons
• Sensory neurons


  • Carry impulses from sense organs to central nervous system
• Relay neurons


  • Found inside central nervous system, connect sensory and motor neurons
• Motor neurons


  • Carry impulses from central nervous system to effectors (muscles or glands)
• Stimulus


  Any change in the environment that can be detected by sensory neurons
• Receptor


  Structure that can detect a stimulus and generate an electrical impulse
• Effector


  Structure, often a muscle or gland, that responds to a signal from the nervous system resulting in a specific action or behavior
• Voluntary response


  Conscious action, something you do on purpose because you choose to
• Involuntary response


  Quick and automatic reaction to a stimulus that happens without thinking
• Reflex arc


  Pathway that a nerve impulse follows in an involuntary or reflex response
• Reflex arc process


  1. Stimulus detected by receptor

  2. Receptor converts stimulus to electrical impulse

  3. Impulse travels along sensory neuron

  4. Impulse passes to relay neuron

  5. Relay neuron connects to motor neuron

  6. Motor neuron carries impulse to effector

  7. Effector carries out response
• Synapse


  Junction between two neurons where messages are transmitted chemically rather than electrically
• Synapse function

  1. Neurotransmitter molecules released from vesicles into synaptic gap

  2. Neurotransmitter molecules diffuse across gap

  3. Neurotransmitter molecules bind to receptor proteins on next neuron

  4. Impulse stimulated in next neuron
• Synapses ensure impulses travel in one direction only