Nervous System

• What do receptors and effectors do?


  Receptors detect stimuli

  Effectors respond to stimuli.
• What is the peripheral nervous system?

  It is made up of neurons that connect the central nervous system to the rest of the body. It has 2 different systems: the autonomic nervous system and the somatic nervous system.
• What is the autonomic nervous system?


  It controls unconscious activities. It has 2 divisions: the sympathetic nervous system and the parasympathetic nervous system.
• What do the sympathetic and parasympathetic nervous system do?

  The sympathetic nervous system gets the body ready for action. The parasympathetic nervous system calms the body down.
• How do neurons transmit information around the body?

  Dendrites receive information from other neurons.

  The info passes along the axon, that is insulted by the myelin sheath which speeds up transmission, in the form of an electrical impulse towards the synaptic knob.

  There’s a small gap between neurons called the synapse.

  Neurotransmitters are chemicals that are released from the synaptic knob that pass across the synapse to pass the signal to the dendrites of the next neuron.
• What are sensory neurons?

  The neurons that transmit electrical impulses from receptors to the CNS
• What are relay neurons?

  Neurons that transmit electrical impulses between sensory neurons and motor neurons.
• What are motor neurons?

  Neurons that transmit electrical impulses from the central nervous system to effectors.
• What is the transmission of information to and from the central nervous system?

  Stimulus > Receptors > Central nervous system > Effectors > Response
• What are reflexes?

  Automatic responses to stimuli. They bypass the conscious brain and instead go through the spinal cord or an unconscious part of the brain. These rapid responses help us avoid damage.
• What is a synapse?

  A junction between a neuron and another neuron, or between a neuron and an effector cell
• How is information transmitted between two neurons?

  The presynaptic knob contains presynaptic vesicles that are filled with neurotransmitters

  When an electrical impulse reaches the end of the neuron, it causes the vesicles to release the neurotransmitters

  The neurotransmitters are diffused across the synaptic clef and they bind to specific receptors on the postsynaptic membrane

  When neurotransmitters bind to receptors, it can lead to triggering an electrical impulse in the next neuron

  The remaining neurotransmitters are removed from the synaptic clef so the response doesn't keep happening
• How do synapses ensure that nerve impulses are unidirectional?

  The specific receptors are only on the postsynaptic membrane, which means that the neurotransmitters can only travel in one direction
• What is an excitatory and inhibitory neurotransmitter?


  Excitatory - increase the likelihood that an electrical impulse will be triggered in the postsynaptic neuron.

  Inhibitory - decrease the likelihood that an electrical impulse will be triggered in the postsynaptic neuron.
• Examples of neurotransmitters?

  Serotonin

  Dopamine

  GABA

  Noradrenaline