Biopsychology

• Neurons

  Function

  • Neurons enable communication with in the nervous system
• What are the main structural components of a neuron


  Dendrites

  cell body

  Axon

  Myelin sheath

  Nodes of ranvier

  Axon terminals/ terminal buttons
• Describe a dendrite


  extend from the cell body and recieve info from other nerurons they also carry functional info towards cell body
• describe the cell body


  contains genetic material of the cell, it takes all the info from dendrites and puts it together, if signal is strong enough then a action potential/ electrical signal is sent down the axon
• describe the myelin sheath

  insulator material that prevents the signal degrading
• axon


  carries messages away from cell body
• nodes of ranvier


  gaps in myelin sheath to speed up transmission as the impulse jumps between the gaps if it was continuos it would slow it down
• axon terminals/ terminal buttons


  at the end of axons, make synaptic connections with other cells
• Synaptic transmission


  Transmitting messages from one neuron to another neuron
• Synaptic transmission process


  1. Action potential/electrical impulse reaches presynaptic terminal

  2. Triggers release of neurotransmitters from synaptic vesicles

  3. Neurotransmitters diffuse across synapse

  4. Neurotransmitters bind with receptors on post-synaptic membrane
• Inhibitory neurotransmitters


  Make it less likely for the post-synaptic cell to fire
• Excitatory neurotransmitters


  Make it more likely for the post-synaptic cell to fire
• Determining whether an action potential is produced


  1. Summation (net/total effect) of excitatory and inhibitory inputs

  2. If inhibitory inputs higher than excitatory, they cancel out excitation and inhibit action potential

  3. If excitatory inputs higher than inhibitory, they cancel out inhibition and lead to action potential
• Neurotransmitter removal


  1. Reuptake into presynaptic neuron for recycling

  2. Broken down by enzymes
• Sensory neuron function


  Carry message from sense organs to peripheral nervous system towards the brain in the central nervous sytsem
• Sensory neuron structure 


  Long dendrites

  Short axons
• Relay neuron function 


  Connect sensory neuroscience to motor neurons and most are found in cns
• Relay neuron structure 


  Short dendrites

  Short axons
• Motor neuron function


  Connect cns to effectors such as muscles and glands in pns
• Motor neuron structure


  Short dendrites

  Long axon
• Function of NS


  complex network of neurons communicae thru electrical impulses and chemicals across synapse. It collects processes and responds to info in environment and coordinate working of organs and cells
• Ns strucure


  Divided into central and peripheral ns
• The cns is made of the brain and spinal chord

  • Brain- some parts of brain co-ordinate vital functioning of body others involved in higher order thinking duch as problem solving and planning
  • Spinal chord- passes info ti and from brain and connects nerves to pns
• Peripheral nervous system (PNS)


  Transmits messages to and from the CNS; has two divisions - the automatic and somatic nervous system
• Somatic nervous system


  • Under conscious control, uses sensory and motor pathways, transfers information from receptor cells in the sense organs to the CNS and receives information from the CNS that directs muscles to produce voluntary movements
• Autonomic nervous system


  • Operates involuntarily/unconsciously through purely motor pathways, transfers information from internal organs to the CNS and from the CNS to the internal organs, has two main divisions - the sympathetic and parasympathetic nervous system
• Sympathetic nervous system


  • Activates internal organs in response to stressful events, increases heart rate and breathing during the fight or flight response
• Parasympathetic nervous system


  • Involved in the rest and digest response, slows down the activity of internal organs after a threat passes
• Endocrine system


  Regulates the activity of cells and organs and controls vital physiological processes in the body, glands release hormones into the bloodstream that affect any cell in the body that has a receptor for that particular hormone
• Stress response


  1. Amygdala sends distress signal to hypothalamus

  2. Hypothalamus stimulates sympathetic nervous system

  3. Sympathetic nervous system stimulates adrenal glands to release adrenaline

  4. Adrenaline causes physiological changes (faster heart rate, increased breathing, sweating, dilated pupils, inhibited digestion)
• Return to resting state

  Parasympathetic nervous system returns the body to its resting state
• Localisation of function


  Specific areas of the brain are responsible for particular physical and psychological functions
• Motor area


  • Located at the back of the frontal lobe, responsible for voluntary movement, right hemisphere sends signals to left side of body, left hemisphere sends signals to right side
• Broca's area


  • Located near motor region that controls mouth and vocal cords in left frontal lobe, involved with speech production, enables fluent speech
• Somatosensory area


  • Located at front of parietal lobe, responsible for pressure and pain, amount of area devoted to body part denotes its sensitivity
• Visual area


  • Located at back of occipital lobe, receives and processes visual information, right visual field goes to left visual cortex and vice versa
• Auditory area


  • Located in temporal lobe, responsible for analysing and processing acoustic information, left ear goes to right hemisphere and vice versa
• Wernicke's area


  • Near auditory area in left temporal lobe, responsible for language comprehension, enables speech to be meaningful
• Procedure


  1. Normally the hemispheres are connected by the corpus callosum allowing them to communicate

  2. Sperry tested a group of epileptics who had undergone surgery to severe this part of the brain

  3. He projected an image or word to participant's right visual field and then he showed the same or a different word/picture to their left visual field

  4. In the split brain patients the information cannot be conveyed to the other hemisphere
• Brain plasticity


  The ability of the brain to modify the structure and function based on experience