Nervous System 6.1

​Function of the Nervous System

• Sensory ​Input

  • ​sensory perception from afferent pathways and specialized sensory cells

• ​Integration

  • ​Pathways to the specific areas of the brain and spinal cord

• ​Motor Output

  • ​convert the signal into some form of response

​Sympathetic and Parasympathetic

• Sympathetic

  • "​fight or flight"

    • ​prepares body for perceived danger

      • ​overrides logical thought

• ​Parasympathetic

  • ​"rest, relax, repair"

    • ​maintain long-term health and a healthy balance across all of the body’s function

​Afferent and Efferent

• ​Afferent

  • ​Arrives to the CNS via PNS

• ​Efferent

  • ​Exits CNS via PNS

    • ​somatic response

    • ​autonomic response

​Nevous System Cells

• ​Neurons

  • ​impulse-conducting cell that is the functional unit of the nervous system

• ​Neuroglial Cells

  • ​form a supporting and/or insulating structure for the neurons

​Astrocytes (CNS)

• ​Star shaped

• ​most abundant glial cell

• ​Functions

  • ​forms blood brain barrier

  • ​supportive framework

  • ​regulates blood flow to neurons

  • ​absorbs NTs from synaptic tissue fluid

  • ​Astrocytosis/scerosis

    • ​scar tissue around damaged neurons

  • ​Converts Glucose to lactate for nourishment

​Microglia (CNS)

• ​WBC (white blood cell) macrophages

• ​Functions

  • Homeostatic

    • ​Monitor the environment

  • Activated

    • instigate the inflammatory response

      • ​cytokines

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​Oligodendrocytes CNS)

• ​Adaptive myelinating cells of the CNS

• ​function

  • ​to insulate neurons increasing the speed of impulses along the axon

​Ependymal Cells of the CNS

• ​Ciliated cuboidal to columnar cells that line the brain and spinal cord

• ​Function

  • ​create cerebral spinal fluid

  • ​circulates the CSF

Neuroglial cells of PNS

• ​Satellite Cells

  • ​Forms an envelope around neuronal cell bodies

• ​Schwann cell

  • ​myelinating cells of the PNS

    • ​same function of oligodendrocytes

​Neurogenesis and Misconceptions

• ​Neurons are Mature cells that Do Not divide

• ​Neural stems located in the brain (hypothalamus and deep cerebrum) divide into neuroblast and migrate to different areas of the brain even in adults

• ​Most Brain Tumors are a result of mitotic neuroglial cells

​Neurocircuitry

• ​the dynamic functional network of overlapping and spatially significant interactions that dictate neurological function