Neurons Flashcards
how are neurons classed
according to structure and function
what are the functional classifications of neurons
sensory, motor, interneurons
what are the structural classifications of neurons
multipolar, bipolar and pseudounipolar
what are sensory neurons
these originate in sensory receptors and conduct messages to the CNS. involved in pain, pressure, touch etc
what are motor neurons
originate in the CNS. conduct impulses via efferent neurons from CNS -> PNS, muscle tissue or glands
what are interneurons
form connections between neurons in CNS
what is the basic neuronal structure
cell body, single axon, multiple dendrites
describe the structure of the cell body (aka perikaryon/soma)
- has nucleus and perinuclear cytoplasm
- rER and polyribosomes are also present, the combination of these two organelles = nissl bodies.
- axon hillock = where axon arises
3 filamentous structures can also be found - microtubules, neurofilaments, microfilaments
what two processes extend from the soma
a single axon and one or more dendrites
what is the function of the cell body
main nutritional and metabolic region of the neuron. receives signals from the other cells ad sends them toward the axon
describe the structure + function of dendrites
have a branched structure that results in synaptic terminals which allow neurons to receive and integrate multiple impulses. they are the major sites of information input into the neuron
receives signals from other cells and sends them towards the axon
describe the structure and function of axon
a cylindrical extension from the axon hillock.
initial segment = portion of axon from origin to the beginning of myelin sheath. terminates on other neurons/effector organs as small branches with swellings called terminal boutons which form synapses.
action potentials are conducted to other neurons/effector organs via axon
define anterograde
from soma to axon terminal
define retrograde
from axon terminal to soma
what is grey matter
cell bodies + dendrites
