Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
47 Cards in this Set
- Front
- Back
|
when a nerve respond to a stimulus (smell) what flows into the cell
|
sodium
|
|
|
when enough sodium flows into the axon, what occurs?
|
action potential
|
|
|
For action potential to occur, enough sodium must flow into the axon to do what?
|
raise the charge to a certain threshold.
|
|
|
What are changes in axon charge that occur below the threshold for an action potential (can't smell anything yet) called?
|
graded potential
|
|
|
During action potential, what are sodium ions that enter the axon attracted to?
|
negative charges
|
|
|
When enough positive charge accumulates farther down the axon, and permeability to sodium increases, what begins?
|
a new action potential.
|
|
|
After the influx of sodium, how does the axon membrane return to resting charge?
|
by releasing potassium
|
|
|
What is resting membrane potential?
|
-70mv
|
|
|
What is the threshold for an action potential?
|
-55mv
|
|
|
What happens at +30mv?
|
outflow of potassium brings charge back down
|
|
|
The increase in charge from -70mv to +30mv is called what?
|
depolarization
|
|
|
The decrease in charge from +30mv to -70mv is called what?
|
re-polarization
|
|
|
During an action potential, enough potassium flows out to bring charge below resting membrane potential (-70mv) is called what?
|
hyper-polarization
|
|
|
During depolarization and some re-polarization, no new action potentials can be generated, what is this called?
|
absolute refractory period
|
|
|
During repolarizaion, when new action potentials can be generated, what is the new threshold for new action potentials?
|
higher than -55mv
|
|
|
What is the period of time called during an action potential when new action potentials can be generated by stronger stimuli?
|
Relative refractory period
|
|
|
What effects the rate of action potentials?
|
strength of a stimulus and axon diameter
|
|
|
What are the gaps between Schwann celss called?
|
Nodes of Ranvier
|
|
|
When nerve impulse appears to jump down the axon, what is the nerve impulse called?
|
Saltatory conduction
|
|
|
A single neuron receives action potentials from many other neurons through its what?
|
dendrites
|
|
|
For a new action potential to begin, action potentials mus arrive from enough dendrites and in a short enough period of time. What are these two factors called?
|
Spatial and Temporal summation
|
|
|
What are the two types of synapses or connections between neurons?
|
Electrical and chemical.
|
|
|
Where are electrical synapses found?
|
in the brain
|
|
|
Most synapses are
|
chemical synapses
|
|
|
when neurons communicate by releasing neurotransmitter across a small space between cells, what is this called?
|
Synapse.
|
|
|
The neuron before a synapse is the what?
|
sending, presynaptic neuron
|
|
|
the neuron after a synapse is what?
|
the receiving, postsynaptic neuron
|
|
|
what is the space between neurons called?
|
the synaptic cleft
|
|
|
Most synapses are
|
axodendritic (between axon of one neuron and dendrite of another)
|
|
|
When an action potential arrives at the end of an axon, what is it signal?
|
the influx of calcium
|
|
|
What is the most common neurotransmitter?
|
acetylcholine
|
|
|
What neurotransmitter is involved with pleasurable feelings?
|
Dopamine
|
|
|
In the CNS, the brain and spinal cord, what is the myelin sheath around axons?
|
white matter
|
|
|
In the CNS, what is the concentrations of cell bodies called?
|
Gray matter
|
|
|
in the CNS what are areas of gray matter in the brain called?
|
nuclei
|
|
|
In the CNS, what are areas of gray matter in the spinal cord called?
|
horns
|
|
|
In the PNS, what is gray matter called?
|
ganglia
|
|
|
What is 1/8 in think and weighs close to 1/2 the weight of the brain?
|
Cerebral cortex
|
|
|
There is no cortex of gray matter where?
|
in the spinal cord
|
|
|
Nerves that carry sensory information to the CNS are what?
|
afferent
|
|
|
Nerves that carry motor information away from the CNS are
|
efferent
|
|
|
What are the three major lobes of the brain?
|
Two cerebral hemispheres and the cerebellum
|
|
|
What are the wormlike ridges of the brain called?
|
Gyri
|
|
|
What are the grooves between the gyri called?
|
sulci
|
|
|
What is the the deeper groove between the two cerebral hemispheres called
|
longitudinal fissure
|
|
|
Chambers within the cerebral hemispheres that are filled with cerebrospinal fluid is called
|
Ventricles
|
|
|
Cerebrospinal fluid diffuses from several capillary beds on the ventricles called
|
choroid plexus
|
