relatively short chains of amino acids that
serve as neurotransmitters that operate via
metabotropic receptors.
Glutamate
the neurotransmitter at the
neuromuscular junction. Is
also an amino acid.
dopamine
an amine made from tyrosine.
It affects sleep mood, attention,
and learning.
serotonin
an amine made from
tryptophan. It affects sleep,
mood, attention, and learning.
norepinephrine
an amino acid made from tyrosine.
Also is an excitatory neurotransmitter
in the autonomic nervous system.
Neuron Structure
axon
an extension that transmits
signals to other cells. Axons
are longer than dendrites.
synapse
the branched end of an axon
that transmits information to
another cell at a junction.
dendrites
numerous highly
branched extensions
attached to the cell body
neurotransmitters
chemical messengers that
pass information from the
transmitting neuron to the
receiving cell.
Neuron Communication
ligand-gated
ion channel
the receptor protein that binds and
responds to neurotransmitters.
Binding to a particular part of the
receptor opens the channel & allows
specific ions to diffuse across the
membrane.
excitatory
postsynaptic
potential (EPSP)
when the ligand-gated ion channel
opens (and its permeable to both
sodium and potassium), the membrane
potential depolarizes. This brings the
membrane potential to a threshold.
temporal summation
when 2 EPSPs occur at a single
synapse in rapid succession that the
neuron's membrane potential has
not returned to resting potential
before the arrival of the second EPSP.
spatial summation
EPSPs produced nearly
simultaneously by different
synapses on the same postsynaptic
neuron can cause this.
Ion pumps
membrane potential
the charge difference, or
voltage of energy in a cell
ion channels
pores formed by clusters
of specialized proteins that
span the membrane
sodium-potassium
pump
pump uses ATP hydrolysis
to actively transport
sodium out of the cell and
potassium into the cell