BHSC 3214 Mod.1

  1. How does the nervous system know what is going on?
    Sensory receptors provide sensory input
  2. Where does the sensory input come from?
    -Outside and inside the body

    -Environmental and visceral changes
  3. Name 5 sensory receptors
    Free nerve endings (pain and temperature receptors)

    Meissner’s corpuscle (touch receptors)

    Lamellar corpuscle (deep pressure receptor)

    Golgi tendon organ (proprioceptor)

    Muscle spindle (proprioceptor)
  4. What happens to the sensory input?
    Information travels to the integration centre to determine the appropriate response
  5. What happens as a result of the sensory input and integration of the information?
    • An appropriate response occurs
    • (Eg. A muscle contracts or a gland secretes its product)
  6. Major divisions of the nervous system and their components
    1.Central Nervous System (CNS)

    • i) brain
    • ii) spinal cord

    2. Peripheral Nervous System (PNS)

    • i) cranial nerves
    • ii) peripheral nerves
  7. Structural Classification and functions of the Central nervous system (CNS)
    Structure: organs, brain, spinal cord.

    Function: integration, command center, interprets incoming sensory information, issues outgoing instructions
  8. Structural Classification and function of the Peripheral Nervous System
    Structure: nerves extending from the brain and spinal cord. spinal nerves—carry impulses to and from the spinal cord-cranial nerves—carry impulses to and from the brain

    Functions: serve as communication lines amongsensory organs, the brain and spinal cord, and glands or muscles
  9. 3 Functions of the Nervous System

    Sensory input—gathering information to monitor changes occurring inside and outside the body, changes = stimuli

    Integration-to process and interpret sensory inputand decide if action is needed.

    Motor output- a response to integrated stimuli.The response activates muscles or glands.
  10. Functional Classification of the Peripheral Nervous System
    • Sensory (afferent) division- nerve fibers that carry information to the central nervous system.
    • Motor (efferent) division- nerve fibers that carry impulses away from the central nervous system
  11. Motor (efferent) division: Two subdivisions
    • Somatic nervous system: voluntary, consciously controls skeletal muscles.
    • Autonomic nervous system: involuntary, automatically controls smooth and cardiac muscles and glands. Further divided into the sympathetic and parasympathetic nervous systems.
  12. Nervous Tissue: Support Cells
    Support cells in the CNS are grouped together as “neuroglia” or simply “glial cells”

    Glial cells are capable of replication

    General functions: support, insulate, protectneurons.
  13. Astrocytes
    Abundant, star-shaped cells.

    Functions: brace neurons, form barrier between capillaries and neurons, blood-brain barrier, control the chemical environment ofthe brain, and mop up leaked potassium.
  14. Microglia
    Spider like phagocytes

    Function: dispose of debris, bacteria, and dead brain cells.
  15. Ependymal Cells
    Functions: line cavities of the brain and spinal cord, control composition of cerebrospinal fluid, ciliated, assist with circulation of cerebrospinal fluid.
  16. Oligodendrocytes
    Wrap around axons of neurons within the central nervous system, membranous extensions of the oligodendrocyte cell membrane, produce a fatty insulating cover for the axon called the myelin sheath.
  17. Schwann Cells
    • Form the myelin sheath in the peripheral nervous system,
    • (differences between the CNS and PNS cells that produce the myelin sheath several cells are needed to form the myelin sheath of a single axon within the PNS)
  18. Satellite Cells
    Protect neuron cell bodies, found around ganglia of the peripheral nervous system.

    A ganglion is a collection of nerve cell bodies found outside the central nervous system.
  19. Neurons = nerve cells
    Cells specialized to transmit messages.

    Major regions of neurons- cell body: nucleus and metabolic center of the cell, processes:fibers that extend from the cell body.
  20. What organelle would you expect to
    see in the nerve cell body if replication were possible?
    Neurons are unable to replicate because they lack centrioles.
  21. Dendrites
    conduct impulses toward the cell body, neurons may have hundreds of dendrites.
  22. Axons
    Conduct impulses away from the cell body, neurons have only one axon arising from the cell body at the axon hillock.

    -End in axon terminals
  23. Axon Terminals
    • -contain vesicles with neurotransmitters
    • -axon terminals are separated from the next neuron by a gap
    • -synaptic cleft, gap between adjacent neurons
    • -synapse, junction between nerves, junction between a nerve and a muscle cell
  24. How is information propagated from one nerve cell to another ?

    What allows the signal to be propagated quickly?
    The signal is an electrical signal, causes changes in the polarity of the cell membrane of the neuron or muscle cell.

    The myelin sheath.
  25. Myelin Sheath
    Whitish, fatty material covering axons, schwann cells produce myelin sheaths in jelly roll-like fashion around axons (PNS), nodes of ranvier, gaps in myelin sheath along the axon.

    Oligodendrocytes produce myelin sheaths around axons ofthe CNS.
  26. Nuclei
    Clusters of cell bodies

    Basal nuclei within the white matter of the cerebrum of the central nervous system .

    Ganglia collections of nerve cell bodies outside the central nervous system.

    Dorsal root ganglia of the spinal cord sensory nerve cell bodies
  27. Definitions
    Tracts-bundles of nerve fibers in the CNS

    Nerves-bundles of nerve fibers in the PNS

    White matter-collections of myelinated fibers

    Gray matter-collections of mostly unmyelinated fibers and cell bodies
  28. Interneurons (association neurons)
    Found in neural pathways in the central nervous system, connect sensory and motor neurons
  29. Multipolar Neurons
    • -many extensions from the cell body
    • -all motor and interneurons are multipolar having many dendrites and an axon
    • -most common type of neuron
  30. Bipolar Neurons
    • -one axon and one dendrite
    • -rare
    • -located in special sense organs such as nose and eye
  31. Unipolar Neurons
    • -have a short single process leaving the cell body
    • -sensory neurons found in PNS ganglia
  32. Functional Properties of Neurons
    • -irritability
    • -ability to respond to stimuli
    • -conductivity
    • -ability to transmit an impulse
Card Set
BHSC 3214 Mod.1
BHSC 3214 Module One