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Biological Psychology: Cells of the Nervous System

Anatomy of Neurons

  • External Features of Neuron

    • Cell Membrane: the semipermeable membrane that encloses the neuron

    • Cell Body: the metabolic center of the neuron; aka soma

    • Dendrites: the short processes emanating from the cell body, which receive most of the synaptic contacts from other neurons

    • Axon Hillock: the cone-shaped region at the junction between the axon and cell body

      • always singular

    • Axon: the long, narrow process that projects from the cell body

      • an axon always starts at the axon hillock

    • Myelin: the fatty insulation around many axons

      • insulation, protection; speeds up transmission or transfer of impulses (most important feature)

    • Nodes of Ranvier: gaps between sections of myelin

    • Terminal Buttons or Buttons: the buttonlike endings of the axon branches, which release chemicals into synapses

    • Synapses or Synaptic Gap or Cleft: the gaps between adjacent neurons across which chemical signals are transmitted

  • Internal Features of a Neuron

    • Mitochondria: sites of aerobic (oxygen-consuming) energy release; powerhouse

    • Nucleus: the spherical DNA-containing structure of the cell body

    • Endoplasmic Reticulum: a system of folded membranes in the cell body; rough portions (those with ribosomes) play a role in the synthesis of proteins; smooth portions (those without ribosomes) playa a role in the synthesis of fats

    • Cytoplasm: the clear internal fluid of the cell

    • Ribosomes: internal cellular structures on which proteins are synthesized; they are located on the endoplasmic reticulum

    • Golgi Complex: a connected system of membranes that packages molecules in vesicles

      • Endoplasmic Reticulum vs Golgi Complex:

        • Endoplasmic Reticulum: synthesize protein

        • Golgi Complex: smooth; packaging

    • Microtubules: tubules responsible for the rapid transport of material throughout neurons

      • transport of substances and nutrients happen

      • Synaptic Vesicles: spherical membrane packages that store neurotransmitter molecules ready for release near synapses

      • Neurotransmitters: molecules that are released from active neurons and influence the activity of other cells

  • Cell Membrane

    • The cell membrane is a lipid bilayer with signal proteins and channel proteins embedded in it

    • Lipid Bilayer: 2 layers of fat molecules

      • embedded are numerous protein molecules that are the basis of many of the cell membranes functional properties

    • Channel Proteins: through which certain molecules can pass

    • Signal Proteins: transfer a signal to the inside of the neuron when particular molecules bind to them on the outside of the membrane

  • Classes of Neurons

    • Unipolar Neuron: a neuron with one process extending from its cell body

      • cell body is smooth

    • Bipolar Neuron: a neuron with 2 processes extending from its cell body

    • Multipolar Neuron: a neuron with more than 2 processes extending from its cell body

      • one axon multiple dendrites; can receive or send out efferent axon away; away from axon (going out the neuron); motor or afferent to the neuron; sensory = accept; sensory

    • Multipolar Interneuron: neurons with a short axon or no axon at all

      • function is to integrate neural activity within a single brain structure, not to conduct signals from one structure to another

      • in between 2 other neurons; serves to conduct impulses through another neuron without the use of axon

    • Neurons and Neuroanatomical Structure

      • Nuclei (singular = nucleus): clusters of cell bodies in the central nervous system

      • Ganglia (singular = ganglion): clusters of cell bodies in the peripheral nervous system

      • Tracts: bundles of axons in the central nervous system

      • Nerves: bundles of axons in the peripheral nervous system

Glia: The Forgotten Cells

  • Glia: most common type of cells in the nervous system

  • Major Types of Glia

    • Oligodendrocytes: glial cells with extensions that around the axons of some neurons of the central nervous system

      • extensions are rich in myelin, a fatty insulating substance, and the myelin sheaths they form increase the speed and efficiency of axonal conduction

      • “cake roll”

    • Schwann Cells: similar function as oligodendrocytes in the peripheral nervous system

      • only Schwann cells can guide axonal regeneration (regrowth) after damage

      • “sandwich”

  • Major Types of Glia

    • Microglia: smaller than other glial cells

      • respond to injury or disease by multiplying, engulfing cellular debris or even entire cells, and triggering inflammatory responses

      • have immune system-like responsibilities in the brain, and they play a role in the regulating of cell death, synapse formation, and synapse elimination

      • rehabs the cell until cells are fully functional

    • Astroglia: largest of the glial cells; support and provide nourishment for neurons and form part of the blood-brain barrier

      • have the ability to contract or relax blood vessels throughout the brain

      • establish and maintain connections between neurons

Biological Psychology: Cells of the Nervous System

Anatomy of Neurons

  • External Features of Neuron

    • Cell Membrane: the semipermeable membrane that encloses the neuron

    • Cell Body: the metabolic center of the neuron; aka soma

    • Dendrites: the short processes emanating from the cell body, which receive most of the synaptic contacts from other neurons

    • Axon Hillock: the cone-shaped region at the junction between the axon and cell body

      • always singular

    • Axon: the long, narrow process that projects from the cell body

      • an axon always starts at the axon hillock

    • Myelin: the fatty insulation around many axons

      • insulation, protection; speeds up transmission or transfer of impulses (most important feature)

    • Nodes of Ranvier: gaps between sections of myelin

    • Terminal Buttons or Buttons: the buttonlike endings of the axon branches, which release chemicals into synapses

    • Synapses or Synaptic Gap or Cleft: the gaps between adjacent neurons across which chemical signals are transmitted

  • Internal Features of a Neuron

    • Mitochondria: sites of aerobic (oxygen-consuming) energy release; powerhouse

    • Nucleus: the spherical DNA-containing structure of the cell body

    • Endoplasmic Reticulum: a system of folded membranes in the cell body; rough portions (those with ribosomes) play a role in the synthesis of proteins; smooth portions (those without ribosomes) playa a role in the synthesis of fats

    • Cytoplasm: the clear internal fluid of the cell

    • Ribosomes: internal cellular structures on which proteins are synthesized; they are located on the endoplasmic reticulum

    • Golgi Complex: a connected system of membranes that packages molecules in vesicles

      • Endoplasmic Reticulum vs Golgi Complex:

        • Endoplasmic Reticulum: synthesize protein

        • Golgi Complex: smooth; packaging

    • Microtubules: tubules responsible for the rapid transport of material throughout neurons

      • transport of substances and nutrients happen

      • Synaptic Vesicles: spherical membrane packages that store neurotransmitter molecules ready for release near synapses

      • Neurotransmitters: molecules that are released from active neurons and influence the activity of other cells

  • Cell Membrane

    • The cell membrane is a lipid bilayer with signal proteins and channel proteins embedded in it

    • Lipid Bilayer: 2 layers of fat molecules

      • embedded are numerous protein molecules that are the basis of many of the cell membranes functional properties

    • Channel Proteins: through which certain molecules can pass

    • Signal Proteins: transfer a signal to the inside of the neuron when particular molecules bind to them on the outside of the membrane

  • Classes of Neurons

    • Unipolar Neuron: a neuron with one process extending from its cell body

      • cell body is smooth

    • Bipolar Neuron: a neuron with 2 processes extending from its cell body

    • Multipolar Neuron: a neuron with more than 2 processes extending from its cell body

      • one axon multiple dendrites; can receive or send out efferent axon away; away from axon (going out the neuron); motor or afferent to the neuron; sensory = accept; sensory

    • Multipolar Interneuron: neurons with a short axon or no axon at all

      • function is to integrate neural activity within a single brain structure, not to conduct signals from one structure to another

      • in between 2 other neurons; serves to conduct impulses through another neuron without the use of axon

    • Neurons and Neuroanatomical Structure

      • Nuclei (singular = nucleus): clusters of cell bodies in the central nervous system

      • Ganglia (singular = ganglion): clusters of cell bodies in the peripheral nervous system

      • Tracts: bundles of axons in the central nervous system

      • Nerves: bundles of axons in the peripheral nervous system

Glia: The Forgotten Cells

  • Glia: most common type of cells in the nervous system

  • Major Types of Glia

    • Oligodendrocytes: glial cells with extensions that around the axons of some neurons of the central nervous system

      • extensions are rich in myelin, a fatty insulating substance, and the myelin sheaths they form increase the speed and efficiency of axonal conduction

      • “cake roll”

    • Schwann Cells: similar function as oligodendrocytes in the peripheral nervous system

      • only Schwann cells can guide axonal regeneration (regrowth) after damage

      • “sandwich”

  • Major Types of Glia

    • Microglia: smaller than other glial cells

      • respond to injury or disease by multiplying, engulfing cellular debris or even entire cells, and triggering inflammatory responses

      • have immune system-like responsibilities in the brain, and they play a role in the regulating of cell death, synapse formation, and synapse elimination

      • rehabs the cell until cells are fully functional

    • Astroglia: largest of the glial cells; support and provide nourishment for neurons and form part of the blood-brain barrier

      • have the ability to contract or relax blood vessels throughout the brain

      • establish and maintain connections between neurons