Week 3- biological bases of behavior

• Neurons

  Receive and deliver messages around the body
• Types of neuron

  • Sensory
  • Interneurons
  • Motor-neurons
• Sensory neurons

  Help to sense with 5 senses
• Interneurons

  Process info and pass it on
• Motor-neurons

  Help to react (pulling hand away when something hot)
• Structure & Function of neuron

  • Dendrites
  • Soma (cell body) - contains genes and DNA
  • Axon - long part of cell body covered by protective sheet (myelin sheath)
  • Myelin sheath - speeds up info transmission speed
  • Axon terminal - info released as neurotransmitters
• Resting potential

  Axon will be filled with - charged inside particle but outside is +, Brain not actively sending signals (on a break)
• Action potential

  When neuron gets activated by a trigger (sensory signal), All or none response (either on or off no in between), Travels down axon 2-200mph
• Excitatory messages

  Make cell lose - charge, Depolarization - getting pumped up and sending signal
• Inhibitory messages

  Make cell more - charged, Hyperpolarization - Prevents action
• Saltatory conduction


  Lets electrical impulses jump between gaps in the myelin sheath, enabling fast and efficient communication in the nervous system
• Synapse

  Gap between terminal button and dendrites, Chemicals released into synapse from terminal button, Synapse is the bridge where they pass the signal
• Neurotransmitters


  • Acetylcholine - muscle contraction
  • Dopamine - keeps things under control
  • Serotonin - crucial for sleep and dreaming
  • Gamma -amino - butyric acid (GABA) - regulates anxiety levels
• Drugs in the brain

  • Agonists - mimic action of neurotransmitters (nic mimics acetylcholine)
  • Antagonists - helps relax muscle by blocking action of neurotransmitters
  • Neuromodulators - increase or decrease mood and effects effectiveness of other neurotransmitters
• Function of nervous system

  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)
• Central nervous system (CNS)


  Brain and spinal cord (sends instructions)
• Peripheral nervous system (PNS)

  • Somatic system (voluntary actions like raising hand)
  • Automatic (blinking, breathing)
  • Sympathetic (prepares for emergencies)
  • Parasympathetic (calms body down)
• Structure of the brain

  • Hindbrain (back) - Medulla, Pons, Cerebellum
  • Midbrain - Tectum (visual and auditory), Substantia nigra (visual and auditory)
  • Forebrain - Cerebral cortex (outer layer of forebrain), Thalamus, Hypothalamus (survival needs), Limbic system (emotions and memory)
• Hemispheric Lateralization


  Divisions of functions of left and right hemisphere of brain
• Hemispheric specialization


  • Left hemisphere - logical thinking, verbal thinking, controls right side body
  • Right hemisphere - emotion, spatial task, creativity, controls left side of body
• Corpus callosum


  Acts as bridge between hemispheres to help info to be transferred across them, if damaged it effects info transmission and disrupts logical and creative thinking
• Endocrine system


  Produces and secretes hormones, Regulates internal functions and promotes growth
• Hypothalamus


  Main part in endocrine system
• Pituitary gland


  Releases/controls hormones
• Heredity and behavior


  Determines physical and psychological traits, Nature and nurture
• How genes work


  • 23 pairs of chromosomes (46 total)
  • 1 chromosome from father, 1 from mother
  • Dominant genes: in phenotypes
  • Recessive genes
• Phenotype


  What you can observe about a trait like weight etc, Is influenced by genotypes and environment