nerve cells that transfer information within the body
neurons
gives the neurons nourishment
glia
allows for the sensory input/motor output
Peripheral nervous system (PNS)
allows for integration/information comes in and is interpreted
Central nervous system (CNS)
Neurons maintain a _______ ______.
membrane potential
________ ______ can be measured by inserting electrodes into cells.
action potentials
There is a ______ _____ after the depolarization during which time
the sodium channels remain inactivated.
refractory period
The axons of motor and sensory neurons are bundled together to form _____.
nerves
At some synapses, there is a direct electrical connection between the
neurons, but most are ______ synapses.
chemical
The cone snail kills prey with venom that ______ neurons.
disables
_______ are the structural and functional units of the nervous system.
neurons
What are the two types of signals neurons use to communicate?
electrical and chemical
Neurons are supported by ____.
glia
_______ collect chemical information.
dendrites
The information is transferred down the _____ _____ then down to the axon.
axon hillock
Then, it goes down the ______ ______ and there is a release of more
chemical messengers.
synaptic terminals
Higher concentration of ____ on the outside.
Na+
Higher concentration of ____ on the inside.
K+
The sodium potassium pump spends ____ energy.
ATP
______ signals are transmitted down the neuron as voltage changes
open and close gated channels in the membrane.
electrical
Why are impulses only propagated in one direction?
the refractory period
In the PNS, ______ cells wrap around the axons creating layers of
membrane lipids that are poor conductors of electricity.
Schwann
In the CNS ______ cells wrap around the axons creating layers of
membrane lipids that are poor conductors of electricity.
oligodendrocytes
The _____ _____ results in faster transmission of the electrical signal.
myelin sheath
Signals are passed between neurons at junctions called _____.
synapses
What holds neurons together at a synapse?
membrane proteins
if multiple excitatory signals come down a single axon close enough
together in time, threshold depolarization may be reached
temporal summation
if multiple excitatory signals are transmitted from several neurons
at the same time, threshold may be reached
spatial summation
if the summation of signals does not depolarize to threshold, no
______ ______ is generated.
action potential