Brain function 1 Flashcards
what is a neuron ?
chemical and electrical info and communication cells
variable sizes and structure throughout the nervous system
what is the neurons cellular constituents ?
microtubules (transportation)
neurofibrils (structural support)
Nissl substances (protein synthesis )
what are the three components of the neuron ?
cell body (soma )
dendrites
axons
where is cell body located ?
The CNS
What is dendrites ?
receptive portion of the neuron
sends impulses to the cell body
what is the dendritic zone ?
receptive portion of the neuron receives stimulus and continues further conduction
what is the axon?
carry nerve impulses away from cell body
what is axon hillock ?
is a cone shaped , organelle - free area where the axon leaves the cell body
where does action potential begins ?
axon hillock
what insulates the axon ?
myelin maintained and formed by the Schwann cells
what are nodes of Ranvier ?
regular interruptions of the myelin sheath
what is the neurilemma ?
Schwann sheath
how can neurons be classified ?
basis of the number of processes extending from cell body
what are multipolar neurons ?
each with one axon and two or more dendrites
most common
what are bipolar neuron ?
with one dendrites and one axon
comprise the sensory neurons of the retina , olfactory epithelium and the inner ear
what are unipolar / pseudounipolar neuron ?
includes other sensory neurons
each have single process that bifurcates close to the perikaryon
longer branch extending to peripheral ending to CNS
What are anaxonic neurons ?
with many dendrites but no true axon
do not produce action potential
is a motor neuron multipolar ?
yes
what are sensory neurons ?
transmits impulses from peripheral sensory receptor to the CNS
Are transmitted via an afferent pathway
(Afferent = arrive )
what are associational / interneurons ?
transmits impulses neuron to neuron
what are motor neurons ?
transmits impulse from the CNS to an effector organ
transmitted via efferent pathway ( efferent = exit)
what is neuroglia ?
nerve glue
what are the four types of neuroglia ?
astrocyte
microglial cell
ependymal cell
oligodendrocyte
what are Schwann cells also called ?
neurolemmocytes