Chapter 3 Flashcards
(39 cards)
Neuron
nerve cell specialized for
communication
Function of a neuron
The functioning of our brain depends on continual cross-talk among neurons—nerve
cells specialized for communication with each other. Neurons receive chemical messages from other neurons by way of synaptic contacts with dendrites. Next, neurons send action potentials
down along their axons, some of which are coated with myelin to make the electrical signal travel faster.
Dendrites
Like the receivers on our cell phones, these numerous dendrites spread
out to “listen in” on conversations from neighboring neurons and pass them on to the cell
body
Axons and Axon Terminals
“cell phone transmitters” They’re specialized for sending messages to other neurons. These
long tail-like extensions are usually very thin near the cell body
Neurotransmitters
chemical messenger specialized
for communication from neuron to
neuron
Synaptic Vesicle
spherical sac containing
neurotransmitters. Think of this like a gel capsule. Once swallowed and inside your stomach, the outside dissolves and the medicine inside it moves down our digestive tracts
Synapse
Once released from the synaptic vesicle, neurotransmitters enter the synapse,
a tiny fluid-filled space between neurons through which neurotransmitters travel
Synaptic Cleft
a gap into which neurotransmitters are released from the
axon terminal. This gap is surrounded by small patches of membrane on each side, one on
the sending axon of the first neuron and the other on the receiving dendrite of the second
neuron
Glial (glue) Cells
cell in the nervous system that plays a role in the formation of myelin and the blood–brain barrier, responds to injury, removes debris, and enhances learning and memory
Myelin Sheath
glial cells wrapped around axons
that act as insulators of the neuron’s
signal. Contains numerous gaps all
the way along the axon called nodes, which help the neuron conduct electricity more efficiently
Resting Potential
electrical charge difference (–60
millivolts) across the neuronal
membrane when the neuron is not
being stimulated or inhibited
Threshold
membrane potential necessary to
trigger an action potential
Action Potential
electrical impulse that travels down
the axon triggering the release of
neurotransmitters. How neurons communicate.
Absolute Refractory Period
time during which another action
potential is impossible; limits
the maximal firing rate
Receptor Site
location that uniquely recognizes a
neurotransmitter. Much as a lock works for only one key, different receptor sites recognize different
types of neurotransmitters
Reuptake
A continually occurring process by which the synaptic vesicle reabsorbs the
neurotransmitter. We can think of release and reuptake of the neurotransmitter as analogous
to letting some liquid drip out of the bottom of a straw (release) and then sucking it back up
Agonists
Opiates, such as codeine
and morphine increase receptor site activity
Antagonists
decrease
receptor site activity. Most medications used to treat the severe mental disorder of schizophrenia block dopamine receptors by binding to them. Botox has the same effect.
Glutamate and GABA
Most common neurotransmitter. The release of glutamate is associated with enhanced learning and memory. When
abnormally elevated, though, glutamate may contribute to schizophrenia and other mental disorders
because in high doses it can be toxic
Acetylcholine
Neurotransmitter that plays roles in arousal, selective attention, memory, and sleep
Monoamines
Norepinephrine, dopamine, and serotonin are the monoamine neurotransmitters. They contain only one amino acid, the building block of proteins.
Anandamide
plays roles in eating, motivation, memory, and sleep. Binds to the same receptors as THC.
Neuropeptides
So human-made opioids, like morphine,
exert their effects by “hijacking” the endorphin system, binding to endorphin receptors and mimicking their effects.
Endorphin
chemical in the brain that plays a
specialized role in pain reduction
