Zusammenfassung der Ressource
Neurons, Synapses,
& Signaling
- Amino acids and amines
- neuropeptides
- 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