Nervous System

• What do neurons do?

  Send and receive messages around the body
• What is in the cell body?


  The nucleus
• What does the nucleus contain?

  the genetic material of the cell
• What is the axon?

  A long extension of the neuron
• What cover the axon?

  Myelin sheath
• What does the myelin sheath do?

  protects and speeds up the nerve impulse as it travels down the axon
• What are at the end of the axon?

  Terminal buttons
• What do terminal buttons do?

  send signals to adjacent cells and connect to the dendrites (or cell body) of another cell.
• What are dendrites?

  They receive messages from other cells
• What are the nodes of Ranvier?

  gaps in the myelin sheath
• What are the three types of neurons?

  Sensory, relay and motor
• What are sensory neurons?

  Carry impulses from sensory receptors (i.e. sight, taste)
• What are relay neurons?


  allow sensory and motor neurons to communicate, they are in the brain and spinal cord.
• What are motor neurons?


  these control muscle movement. The faster the neuron fires the stronger a muscle contraction.
• What is the first stage of the process of synaptic transmission?

  Pre synapse - The electrical nerve impulse travels down the neuron and prompts the release of neurotransmitters into the presynaptic terminal.
• What is the second stage of the process of synaptic transmission?

  Post synapse - neurotransmitters are released into the synaptic fluid of the synaptic cleft. the adjacent neuron then takes up these neurotransmitters and converts them to to an electrical impulse allowing the transmission to be passed on.
• What is an excitatory neurotransmitter?

  They switch the nervous system on
• What is an inhibitory neuron?


  it stops the firing of an impulse
• What is the likely hood of a cell firing determined by?

  EPSP = Excitatory Post Synaptic Potential and IPSP = Inhibitory Post Synaptic Potential
• Name an example of an excitatory neurotransmitter.

  Acetylcholine (ACH) - present in synapses where motor neurons are next to muscle cells. Drugs that block ACH cause fatal muscle paralysis.
• Name and example of an inhibitory neurotransmitter.

  Serotonin - regulates sleep and wakefulness and aggressive behaviour. It is also involved in pain. Serotonin is important in OCD
• Is dopamine excitatory or inhibitory?

  Its both - effects our emotions (including pleasure), level of arousal and voluntary movement - it is a chemical involved in Parkinson's disease
• What are the first two branches of the nervous system called?

  Central nervous system (CNS) and peripheral nervous system (PNS)
• What does the central nervous system do?


  It is concerned with life functions and psychological processes.
• What are the two divisions of the CNS?

  the brain and spinal cord
• What does the brain do?

  Maintains life, involved in higher functions and psychological processes
• What are the three main parts of the brain?

  The brain stem, the cerebellum, the cerebral hemispheres
• What is the brain stem?

  The most primitive part of the brain. Contains basic functions such as sleeping and waking and bodily functions such as breathing and heart rate.
• What is the cerebellum?

  Involved in regulating movement and a sense of balance. Helps regulate smooth and precise movement.
• What are the cerebral hemispheres?

  Performs higher functions, such as hearing, vision and memory
• What is the spinal cord?

  An extension of the brain and runs from the base of the brain down the centre of the back. responsible for reflexes and automatic behaviours. The spinal cord receives and passes messages to and from the brain and connects nerves in the peripheral nervous system.
• What does the PNS do?


  Its made up of neurons that transmit messages to and from the central nervous system
• What are the two divisions of the PNS?

  Somatic nervous system and autonomic nervous system
• What does the somatic nervous system do?

  Sends information to and from senses and to and from the CNS. Its made up of 12 pairs of cranial nerves (nerves that exit from beneath the brain) and 31 pairs of spinal nerves (nerves that emerge from the spinal cord)
• What does the autonomic nervous system do?


  carries out actions which are beyond our conscious control such as digestion, heart beating
• What are the two branches of the autonomic nervous system?

  The sympathetic nervous system and parasympathetic nervous system
• What does the sympathetic nervous system do?

  involved in emergency responses (i.e. fight-or-flight), preparing the body for rapid action. It does this by diverting blood from the stomach to muscles, increasing heart rate, dilating pupils and making the hairs on your body stand on end.
• What does parasympathetic nervous system do?

  supports normal body activity, conserving and storing energy - for example normal digestion occurs when this system is operating. It also acts as a brake in reducing the activities of the sympathetic system.
• What is the fight or flight response?

  a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival
• Where are threating situations detected?

  The amygdala