Psychology AS biological approach

How do we explain behaviour?

• The Brain
  • Behaviour can be explained by the functions of the central nervous system - this is the brain and the spinal chord.
  • (The cerebral cortex)
    • Grey matter
    • Two hemispheres are asymmetrical
    • connected by the corpus callusom.
  • Cerebral hemispheres:
    • Left brain:
      • Logic
      • Language
      • Mathematics
      • Abstraction
      • Reasoning
      • Memory stored in a language format e.g what someone said.
    • Right brain
      • Holistic functioning (dancing, gymnastics)
      • Visual spatial skills
      • Memory stored in auditory, visual and spatial format e.g. where something is.
• Lobes
  • Frontal Lobe
    • Planning, organising, problem solving, selective attention, personality and a variety of 'higher cognitive functions' including behaviour and emotions.
  • Parietal Lobe
    • Processing of sensory input, sensory discrimination, body orientation.
  • Occipital Lobe
    • Primary visual reception area.
  • Temporal Lobe
    • Auditory receptive area and association areas. Expressed behaviour.
  • Cerebellum
    • Balance, posture, co-ordination.
  • Striatum
    • Involved in controlling though and action. Also involved in registering rewarding events.
  • Hippocampus
    • Involved in memory - people suffer from amnesia when the hippocampus is damaged. Particularly involved in learning about spaces - London cab drivers have an enlarged hippocampi.
  • Corpus callosum 
    • A bundle of neurons that links the two brain hemispheres, which are otherwise largely separated.
  • Amygdala
    • Amygdala play a part in the process of emotions and remembering emotional events. They are particularly linked to fear.
  • Hypothalamus
    • A function of the hypothalamus is in thermoregulation - it serves as a thermostat for the body. Also serves other homeostatic functions. Specific areas are associated with hunger and safety. Controls drives.
• The Central Nervous System
  • The spinal chord connects to the brain through the brain stem.
  • Neurological functions located in the brain stem include those necessary for:
    • Survival: breathing, digestion, heart rate, blood pressure.
    • Arousal: being awake and alert.
• Neuron
  • Nucleus
  • Dendrites
  • Axon
  • Axon Terminal
• Synapse synaptic cleft
  • Terminal of sending neuron
  • neurotransmitters
  • receptor
  • dendrite of receiving neuron.
  • Neurotransmitters are carried in mitochondria in the axon terminal, they go through the synaptic cleft through the receptor in the dendrites where the message carries on. Excitatory synapses tell the neuron to carry the message on. Inhibitory synapses tell the neuron not to carry the message on. It is decided through how many excitatory and inhibitory messages are received from the thousands of synapses.

• Hormones
  • The endocrine system
    • The endocrine system is composed of many glands which secrete hormones into the blood system.
    • A hormone is a chemical that travels around the body and affects the actions of the target organs.
    • Hormones influence our thinking, behaviour and emotions and influences our response to stress.
  • Pineal Gland
    • Melatonin
      • Influence on sleep and mood - production of melatonin is inhibited by light and permitted by darkness.
      • Makes us drowsy and reduces body temperature.
  • Adrenal Gland
    • Steroids
      • e.g. cortisol - controls our response to stress
    • Adrenaline
      • Controls how we respond to danger.
  • Gonads
    • Testes
      • Androgens (testosterone)
    • Ovaries
      • Oestrogen and progesterone 

• Genes
  • A gene contains a set of instructions and is a carrier of information.
  • Each individual person has a genotype - this is the genetic composition.
  • Each person has a phenotype which is what the individual becomes when their genes interact with each other…