Nerve Cells & Nerve Impulses The Cells of the Nervous System
Anatomy of Neurons & Glia <ul><li>Two Types of Cells in the Nervous System </li></ul><ul><li>Neurons </li></ul><ul><li>Rec...
Glial Cells <ul><li>Astrocytes </li></ul><ul><li>Absorbs chemicals released by axons </li></ul><ul><li>Involved in reuptak...
Glial Cells <ul><li>Oligodendrocytes </li></ul><ul><li>Builds myelin sheaths around certain neurons in the brain & spinal ...
Glial Cells <ul><li>Radial Glia </li></ul><ul><li>A type of astrocyte that guides the migration of neurons & growth of axo...
Basic Structure of the Neuron <ul><li>Cellular Membrane </li></ul><ul><li>2 layers of fat molecules which allow some small...
Basic Structure of the Neuron <ul><li>Mitochondria </li></ul><ul><li>Provides the cell with energy </li></ul><ul><li>Requi...
Basic Structure of the Neuron <ul><li>Dendrites –  Receives input & sends it to other neurons </li></ul><ul><li>Cell Body ...
Dendritic Spines <ul><li>Short outgrowths found on some dendritic branches </li></ul><ul><li>Changes in dendritic spine de...
Other Neurons <ul><li>Afferent Neurons </li></ul><ul><li>Brings information into a structure </li></ul><ul><li>Efferent Ne...
The Blood-Brain Barrier <ul><li>Keeps Most Chemicals Out of the Brain </li></ul><ul><li>Brain doesn’t have an immune syste...
The Neural Impulse <ul><li>Important Terms </li></ul><ul><li>Electrical Gradient –  the difference in the electrical charg...
The Action Potential <ul><li>Axon Hillock </li></ul><ul><li>Where the Action Potential begins </li></ul><ul><li>Action Pot...
The Myelin Sheath <ul><li>Myelin Sheath </li></ul><ul><li>Myelinated Axons:  axons covered with a myelin sheath </li></ul>...
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Chapter 02: Genetics & Behavior

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Beginning with Mendelian Genetics we look at heritability, evolution and Sociobiology (Evolutionary Psychology).

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Chapter 02: Genetics & Behavior

  1. 1. Nerve Cells & Nerve Impulses The Cells of the Nervous System
  2. 2. Anatomy of Neurons & Glia <ul><li>Two Types of Cells in the Nervous System </li></ul><ul><li>Neurons </li></ul><ul><li>Receive & transmit information to other cells </li></ul><ul><li>Around 100 billion to 1 trillion </li></ul><ul><li>Glia </li></ul><ul><li>Different functions but don’t transmit information like neurons </li></ul><ul><li>Around 9x more than neurons </li></ul>
  3. 3. Glial Cells <ul><li>Astrocytes </li></ul><ul><li>Absorbs chemicals released by axons </li></ul><ul><li>Involved in reuptake </li></ul><ul><li>Removes waste products, especially that created after neurons die </li></ul>
  4. 4. Glial Cells <ul><li>Oligodendrocytes </li></ul><ul><li>Builds myelin sheaths around certain neurons in the brain & spinal cord </li></ul><ul><li>Schwann Cells </li></ul><ul><li>Builds myelin sheaths around certain neurons in the periphery of the body </li></ul>
  5. 5. Glial Cells <ul><li>Radial Glia </li></ul><ul><li>A type of astrocyte that guides the migration of neurons & growth of axons & dendrites during embryonic development </li></ul>
  6. 6. Basic Structure of the Neuron <ul><li>Cellular Membrane </li></ul><ul><li>2 layers of fat molecules which allow some small uncharged particles to flow in & out of the cell </li></ul><ul><li>Protein channels allow a few charged ions to cross the membrane but most chemicals are kept out </li></ul><ul><li>Nucleus </li></ul><ul><li>Structure containing chromosomes </li></ul>
  7. 7. Basic Structure of the Neuron <ul><li>Mitochondria </li></ul><ul><li>Provides the cell with energy </li></ul><ul><li>Requires fuel & oxygen to function </li></ul><ul><li>Ribosomes </li></ul><ul><li>Site of protein synthesis </li></ul><ul><li>Endoplasmic Reticulum </li></ul><ul><li>Thin tubes that transport newly synthesized proteins to locations around the cell </li></ul><ul><li>Proteins may have ribosomes attached </li></ul>
  8. 8. Basic Structure of the Neuron <ul><li>Dendrites – Receives input & sends it to other neurons </li></ul><ul><li>Cell Body – Process input & contains cellular organelles </li></ul><ul><li>Axon – Sends input down & out of the neuron </li></ul><ul><li>Myelin Sheath – Insulates & speeds Neural Impulse </li></ul><ul><li>Presynaptic Terminals – Releases communication chemicals </li></ul>Dendrites Cell Body Axon Myelin Sheath Presynaptic Terminals
  9. 9. Dendritic Spines <ul><li>Short outgrowths found on some dendritic branches </li></ul><ul><li>Changes in dendritic spine density underlie many brain functions, including motivation, learning, and memory. </li></ul><ul><li>Long-term memory is mediated in part by the growth of new dendritic spines </li></ul>
  10. 10. Other Neurons <ul><li>Afferent Neurons </li></ul><ul><li>Brings information into a structure </li></ul><ul><li>Efferent Neurons </li></ul><ul><li>Sends information away from a structure </li></ul><ul><li>Interneurons </li></ul><ul><li>Located entirely within a single structure of the nervous system </li></ul>
  11. 11. The Blood-Brain Barrier <ul><li>Keeps Most Chemicals Out of the Brain </li></ul><ul><li>Brain doesn’t have an immune system </li></ul><ul><li>Endothelial Cells </li></ul><ul><li>Line the walls of the capillaries in a tight formation in the brain </li></ul><ul><li>Active Transport System </li></ul><ul><li>Pumps the necessary chemicals (e.g. glucose) through the barrier </li></ul>
  12. 12. The Neural Impulse <ul><li>Important Terms </li></ul><ul><li>Electrical Gradient – the difference in the electrical charge inside & outside of the cell </li></ul><ul><li>Polarization – difference between an electrical charge between 2 locations </li></ul><ul><li>Resting Potential – when the electrical voltage is negatively higher inside relative to the outside </li></ul><ul><li>Selective Permeability – a cellular membrane that allows some, not all, molecules to pass freely </li></ul><ul><li>Sodium-Potassium Pump – a protein complex on the neural membrane that transports 3 sodium ions outside of the cell while drawing 2 potassium ions into the cell in active transport </li></ul><ul><li>Concentration Gradient – the difference in the distribution of ions between the inside & outside of the membrane </li></ul><ul><li>Hyperpolarization – when the negative charge inside of the axon increases </li></ul><ul><li>Depolarization – when the negative charge inside of the axon decreases </li></ul><ul><li>Threshold of Excitation – the level that a depolarization must reach for an action potential to occur </li></ul><ul><li>Action Potential – when depolarization meets or goes beyond the threshold of excitation </li></ul><ul><li>All-or-none Law – a neuron must have enough stimulation of a certain type to fire or it will not fire </li></ul><ul><li>Refractory Period – period immediately after an action potential when the neuron will resist another action potential </li></ul>
  13. 13. The Action Potential <ul><li>Axon Hillock </li></ul><ul><li>Where the Action Potential begins </li></ul><ul><li>Action Potential </li></ul><ul><li>Regenerated due to Sodium Ions moving down the Axon, Depolarizing adjacent areas of the Membrane </li></ul><ul><li>Moves down the axon by regenerating itself as successive points on the axon </li></ul><ul><li>Refractory Period </li></ul><ul><li>Prevent Action Potentials from moving in the opposite direction </li></ul>
  14. 14. The Myelin Sheath <ul><li>Myelin Sheath </li></ul><ul><li>Myelinated Axons: axons covered with a myelin sheath </li></ul><ul><li>Nodes of Ranvier: short unmyelinated sections an a myelinated axon </li></ul><ul><li>Saltatory Conduction </li></ul><ul><li>The “jumping” of the action potential from node to node </li></ul><ul><li>Multiple Sclerosis: disease where the axon loses myelin </li></ul><ul><li>Local Neurons </li></ul><ul><li>Small Neurons with Short Dendrites & Short or non-existent axons </li></ul>

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