Flashcards in Chap 14 Deck (42):
all nervous tissue in the body
central nervous system
brain and spinal cord
peripheral nervous system
cranial nerves, spinal nerves, and ganglia
sensory and motor nervous systems
sensory nervous system
conveys sensory information to the CNS
motor nervous system
conducts motor commands to the muscles and glands
transmit nerve impulses
completley surround and support neurons
generally neurons have:
a cell body, dendrites and an axon
classified structurally as
unipolar, bipolar, or multipolar depending on the number of attachments to the cell body.
classified functionally as
sensory, motor or interneurons
CNS glial cells:
astrocytes, ependymal cells, microglial cells, and oligodendrocytes
help form the blood brain barrier and regulate tissue fluid composition
line CNS cavities and produce cerebrospinal fluid
act as phagocytes in nervous tissue
mylinate CNS axons
PNS glial cells
satellite cells and nerolemmocytes
support neurons cell bodies in ganglia
mylinate PNS axons
a rapid movement of a charge along a neurons plasma membrane
oligodendrocytes (CNS) and nerolemmocytes (PNS) form a discontinuous mylin sheath along the axon, with small gaps (neurofibril nodes)
small gaps between mylin sheath help conduct impulses faster
associated with a neurolemmocyte but not ensheathed by it.
regeneration of damaged neurons
*limited to PNS axons that are able to regrow under certain conditions*
surrounds individual fasicles
surrounds individual axons
a specialized junction between two excitable cells where a nerve impulse is transmitted
swellings of axons at their end branches
space between the presynaptic and postsynaptic cells
classification of synapses
axodendritic, axosomatic or axoaxonic
most common: presynaptic knobs synapse with postsynaptic dendrites (standard delivery)
between synaptic knobs and the cell body of postsynaptic neuron (express delivery)
least common: presynaptic knob with postsynaptic knob (first class delivery)
*usually overides brains orders
a flow of ions pass from presynaptic cell to postsynaptic cell through gap junctions
nerve impulse causes a release of a chemical neurotransmitter from presynaptic cell that induces response in the postsynaptic cell.
what increases rate of conduction?
presence of a myelin sheath, larger the axon diameter.
groups of interneurons- cordinate and integrate nervous activity.
neurons synapse at a single postsynaptic neuron
spreads information to several neurons
neurons continue to restimulate presynaptic neurons in the circuit.