The Nervous System Flashcards
neurons
specialized cells capable of transmitting electrical impulses, and then translating those electrical impulses to chemical signals
shape matches its function, dictated by the other cells with which it interacts
cell body (soma)
where nucleus of neuron is located
location of the endoplasmic reticulum and ribosomes
dendrites
appendages of neuron emanating directly from the soma
receive incoming messages from other cells
axon hillock
integrates incoming signals
plays an important role in action potentials
sums signals in order to determine whether excitatory enough to initiate an action potential
action potentials
transmission of electrical impulses down the axon
signals can be either excitatory or inhibitory–if excitatory enough, will initiate these
relay electrical impulses down the axon to the synaptic bouton
all-or-nothing messages
cause the release of neurotransmitters into the synaptic cleft
axon
long appendage of neuron that terminates in close proximity to a target structure (a muscle, glad, or other neuron)
myelin
insulates most mammalian nerve fibers to prevent signal loss or crossing of signals
increases the speed of conduction in the axon
produced by oligodendrocytes (CNS) or Schwann cells (PNS)
myelin sheath
maintains the electric signal within one neuron
oligodendrocytes
produce myelin in CNS
Schwann cells
produce myelin in PNS
nodes of Ranvier
at certain intervals along the axon, there are small breaks in the myelin sheath with exposed areas of axon membrane
critical for rapid signal conduction
nerve terminal/ synaptic bouton (knob)
at the end of the axon
enlarged and flattened to maximize neurotransmission to the next neuron and ensure proper release of neurotransmitters
neurotransmitters
chemicals that transmit information between neurons
synaptic cleft
small space between neurons into which the terminal portion of the axon releases neurotransmitters which bind to the dendrites of the postsynaptic neuron
synapse
collectively, the nerve terminal, synaptic cleft, and postsynaptic membrane
nerve
multiple neurons bundled together in the PNS
may be sensory, motor, or mixed
tracts
axons bundled together in CNS
nuclei
how cell bodies of neurons in the same tract are grouped (CNS)
glial cells/ neuroglia
play both structural and supportive roles
- astrocytes
- ependymal cells
- microglia
- oligodendrocytes (CNS) & Schwann cells (PNS)
astrocytes
nourish neurons and form the blood-brain barrier, which controls the transmission of solutes from the bloodstream into nervous tissue
ependymal cells
line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber