Biopsychology

• Divisions of the nervous system

  • Central
  • Peripheral
  • Somatic
  • Autonomic
• Nervous system

  Complex network of nerve cells that carry messages to and from the brain and spinal cord to different parts of the body and so helps all of the body's parts to communicate with each other
• Brain

  Controls the nervous system and oversees the workings of the body, whilst its higher functions provide us with consciousness and makes us who we are
• Components of the nervous system

  • Central nervous system (CNS) - brain and spinal cord
  • Peripheral nervous system - nerve cells that carry information to or from the CNS
• Central nervous system (CNS)

  • Receives sensory input and produces motor responses
• Brain

  • Involved in many different physiological processes
  • Outer layer (cerebral cortex) is involved in higher order thinking, such as problem solving
• Spinal cord

  • Receives and transmits information to and from the brain to the peripheral nervous system (PNS)
  • Responsible for reflex actions
• Peripheral nervous system (PNS)

  Relays nerve impulses via neurons from the CNS to the rest of the body and from the body back to the CNS
• Components of the PNS

  • Somatic nervous system (SNS)
  • Autonomic nervous system (ANS)
• Somatic nervous system (SNS)


  Nerves that we actively control, receives information from sensory receptors and sends this information to the CNS, controls muscle movement
• Autonomic nervous system (ANS)

  Works automatically, controls internal organs and glands of the body
• Subdivisions of the ANS

  • Sympathetic nervous system
  • Parasympathetic nervous system
• Neurons

  The basic building blocks of the nervous system, nerve cells that process and transmit messages through electrical and chemical signals
• Structure of neurons

  • Cell body, dendrites, axon
  • Dendrites receive signals, axon carries impulses, terminal buttons communicate with next neuron
• Synaptic transmission

  1. Action potential reaches terminal buttons

  2. Neurotransmitters released into synaptic gap

  3. Neurotransmitters bind to receptor sites on next neuron

  4. Action potential travels along next neuron
• Excitation

  Leads to post-synaptic neuron becoming positively charged and more likely to fire
• Inhibition

  Leads to post-synaptic neuron becoming negatively charged and less likely to fire
• Neurotransmitter re-uptake


  Neurotransmitter returns back to presynaptic neuron, shortening the effects
• Neurotransmitter inactivation


  Enzymes can "turn off" a neurotransmitter after it has stimulated a post-synaptic neuron
• Information can only travel in one direction at a synapse
• Sensory neurons


  Carry messages from sensory receptors to the CNS
• Relay (inter) neurons


  Connect sensory and motor neurons, allow them to communicate
• Motor neurons


  Connect the CNS to the muscles and glands, release neurotransmitters that trigger muscle movement
• Endocrine system


  Second system in the body that works alongside the nervous system, made up of a network of specialist glands that release hormones
• Some endocrine glands and their hormones

  • Thyroid - Thyroxine
  • Pineal - Melatonin
  • Adrenal medulla - Adrenaline and noradrenaline
  • Adrenal cortex - Glucocorticoids
• Fight or flight response

  Reflex response from the sympathetic nervous system to help an individual react quickly to a threat
• Stages of the fight or flight response

  1. Stressful event

  2. Hypothalamus sends message to pituitary gland

  3. Pituitary releases ACTH

  4. Adrenal glands release adrenaline

  5. Physiological changes lead to fight or flight response
• Physiological changes in the sympathetic branch

  • Increased heart rate
  • Faster breathing rate
  • Pupil dilation
  • Reduced digestive and immune function
  • Muscle tension
• Effects of the parasympathetic branch

  • Decreases heart rate
  • Decreases breathing rate
  • Constricts pupils
  • Stimulates digestion
  • Relaxes muscles
• Freeze response may be the initial reaction to danger, before fight or flight
• Women may adopt a 'tend and befriend' response rather than fight or flight