NERVOUS SYSTEM Flashcards
5 main functions of the nervous system
receiving sensory input
integrating information
controlling muscles and glands
maintaining homeostasis
establishing and maintaining mental activity
major divisions of the nervous system
central NS
peripheral NS
what are the components of the central nervous system
brain
spinal cord
what are the components of the peripheral nervous system
nerves and ganglia outside the brain and spinal cord
2 divisions of the peripheral nervous system
sensory division
motor division
this division of the PNS transmits signals from sensory receptors to the CNS
sensory division
this division of the PNS transmits signals from the CNS to effector organs
motor division
3 major parts of neuron
cell body
dendrites
axon
these are short cytoplasmic extensions in the neuron cell body
dendrites
this part of the neuron conducts action potentials either toward or away from the CNS
axon
axons of motor neurons conduct action potentials ___________ the CNS
away from
axons of sensory neurons conduct action potentials ___________ the CNS
toward
this is a single long process extending from the neuron cell body
axon
types of glial cells
astrocytes
ependymal cells
microglia
oligodendrocytes
schwann cells
satellite cells
other word for glial cells
neuroglia
this type of glial cell provides support and nutrition to the neurons
satellite cells
what is the primary function of schwann cells
provide insulation via myelin sheaths
what types of glial cells provide insulation of the axon
schwann cells
oligodendrocytes
what is the primary function of ependymal cells
these line fluid-filled cavities
these serve as the major supporting cells in the CNS
astrocytes
these act as immune cells of the CNS
microglia
3 types of neurons
multipolar
bipolar
pseudo-unipolar
this type of neuron has many dendrites and one axon
multipolar neuron
how many dendrites and axons does a bipolar neuron have
one dendrite, one axon
this type of neuron appears to have only one axon
pseudo-unipolar neuron
these are cells with processes that can surround multiple neurons
oligodendrocytes
these are small, mobile cells that help fight bacteria and infection
microglia
these are epithelial-like cells
ependymal cells
these are highly branched supporting cells in the CNS
astrocytes
what do you call axons with surrounding myelin sheaths
myelinated axons
these are specialized layers that surround axons
myelin sheaths
what are nodes in ranvier
gaps in myelin sheaths that permit myelin ion movement
these are axons that lack myelin sheaths
unmyelinated axons
junction where the axon of one neuron interacts with another neuron or with cells of an effector organ
synapse
3 major components of synapse
presynaptic terminal (end of axon),
postsynaptic membrane (of another neuron/effector organ),
synaptic cleft (space between the two)
name some neurotransmitters
acetylcholine
dopamine
endorphins
serotonin
GABA
glycine
how many pairs of nerves are there in the PNS
12 pairs of cranial nerves
31 pairs of spinal nerves