questions

• Evolutionary explanation


  States what evolved from what
• Functional explanation


  States why something was advantageous and therefore favored by natural selection
• Biological psychologists conduct much of their research on nonhuman animals because the mechanisms of behavior are sometimes easier to study in a nonhuman species, we are curious about animals for their own sake, we study animals to understand human evolution, and certain procedures that might lead to important knowledge are illegal or unethical with humans
• The "three R's" in the legal standards for animal research

  Reduction, replacement, and refinement
• Minimalist position


  Wishes to limit animal research to studies with little discomfort and much potential value
• Abolitionist position


  Wishes to eliminate all animal research regardless of how the animals are treated or how much value the research might produce
• Monism


  The idea that the mind is made of the same substance as the rest of the universe
• Ontogenetic explanation


  Focuses on how a behavior develops
• Evolutionary explanation


  • Humans have a (tiny) tailbone because our ancient monkey-like ancestors had a tail
• Reason for using animals in biological psychology research

  The nervous system of nonhuman animals resembles that of humans in many ways
• Minimalist


  Favors that animal research is permissible but should be held to a minimum
• Dendrites


  The widely branching structures of a neuron
• Axon


  The long, thin structure that carries information to another cell
• The longest axons occur in the largest animals, such as giraffes and elephants, which have axons that extend from the spinal cord to the feet, nearly 2 meters away
• Interneuron


  Its axon is short because it is contained entirely within one part of the brain
• Major structures that compose a neuron

  • Dendrites
  • Soma (cell body)
  • Axon
  • Presynaptic terminal
• Astrocytes


  The type of glia cell that wraps around the synaptic terminals of axons
• Blood-brain barrier


  Advantage: Keeps out viruses

  Disadvantage: Keeps out most nutrients
• Chemicals that cross the blood-brain barrier passively

  Small, uncharged molecules such as oxygen, carbon dioxide, and water, as well as chemicals that dissolve in the fats of the membrane
• Chemicals that cross the blood-brain barrier by active transport

  Glucose, amino acids, purines, choline, certain vitamins, and iron
• Santiago Ramón y Cajal was responsible for the discovery that the nervous system is composed of separate cells
• Mitochondria


  Have their own genes, separate from those of the nucleus
• Neurons


  Their shape is most distinctive compared to other cells
• Dendritic spines


  Increase the surface area available for synapses
• Efferent axon


  Carries output from a structure
• Astrocytes


  Synchronize activity for a group of neurons
• Microglia


  Remove dead cells and weak synapses
• Fat-soluble molecules


  Can easily cross the blood-brain barrier
• Glucose and amino acids

  Cross the blood-brain barrier by active transport
• The brain's main source of fuel is glucose, and it also needs thiamine to use this fuel
• Resting membrane


  Sodium ions are more concentrated outside the cell, and potassium is more concentrated inside
• Resting membrane


  The concentration gradient tends to drive potassium ions out of the cell, and the electrical gradient draws them into the cell. The sodium-potassium pump also draws them into the cell.
• Hyperpolarization


  An exaggeration of the usual negative charge within a cell, to a more negative level than usual
• Depolarization


  A decrease in the amount of negative charge within the cell
• All-or-none law


  The size and shape of the action potential are independent of the intensity of the stimulus that initiated it. Every depolarization beyond the threshold of excitation produces an action potential of about the same amplitude and velocity for a given axon.
• The all-or-none law does not apply to dendrites, because they do not have action potentials
• Action potential


  During the rise, sodium ions move into the cell because the voltage-dependent sodium gates have opened and sodium is attracted to the inside by both an electrical and a concentration gradient
• Action potential


  After the peak, potassium ions exit the cell, driving the membrane back to the resting potential
• Myelinated axon


  If the nodes were closer, the action potential would travel more slowly. If they were much farther apart, the action potential would travel faster if it could successfully jump from one node to the next, but if the distance becomes too great, the current cannot diffuse from one node to the next and still remain above threshold, so the action potentials would stop.
• Refractory period


  Axon A must have a shorter absolute refractory period, about 1 ms, whereas Axon B has a longer absolute refractory period, about 10 ms