WorksheetsNervous Tissue Part 4
Total questions: 21
Worksheet time: 14mins
Modification of the signal
Neuromodulators modify synaptic transmission
–Hormones or other messengers
–raise or lower number of receptors
–alter neurotransmitter release, synthesis or breakdown
xx
NEURAL Integration
The more synapses a neuron has
•the greater its information-processing capability
•the less its information-processing capability
Look over the chart
Summation refers to
–Adding up all postsynaptic potentials
–Responding to their effect
–Occurs in the trigger zone
Excitatory Post Synaptic Potentials are
shifts in membrane voltage that is closer to threshold and makes the cell more likely to fire
shifts in membrane voltage that is father away from threshold and makes the cell less likely to fire
Inhibitory Post Synaptic Potentials are
shifts in membrane voltage that is closer to threshold and makes the cell more likely to fire
shifts in membrane voltage that is father away from threshold and makes the cell less likely to fire
EPSP's are usually the result of
Na+ flowing into the cell and neutralizing some of the negative charge on the inside of the membrane
K+ flowing into the cell and neutralizing some of the negative charge on the inside of the membrane
In some cases, a neurotransmitter hyperpolarizes the post synaptic cell and makes it more negative than its resting membrane potential. This makes the cell
More likely to fire (EPSP)
Less likely to fire (IPSP)
Some IPSP's are produced by a neurotransmitter opening ligand-gated
Chloride channels, causing Cl- to flow into the cell and make the cytosol more negative.
Another, but less common way is to open selective K+ channels, increasing DIffusion of K+ out of the cell making it more negative
Another, but less common way is to open selective K+ channels, increasing influx of K+ into of the cell making it more negative
Sodium channels, causing Cl- to flow into the cell and make the cytosol more negative.
TRue or False:
EPSP and IPSP don't determine whether a neuron fires or not, but only change the rate of firing by stimulating or inhibiting the production of more action potentials.
TRUE
FALSE
Glutamate and Aspartate are
excitatory brain neurotransmitters that produce EPSPs
inhibitory brain neurotransmitters that produce EPSPs
excitatory brain neurotransmitters that produce IPSPs
GLycine and GABA produce
IPSPs and are therefore inhibitory neurotransmitters
EPSPs and are therefore inhibitory neurotransmitters
TRUE/FALSE:
Acetylcholine and Norepinephrine are excitatory in some cells and inhibitory in other cell. For instance Ach excites skeletal but inhibits cardiac muscle.
TRUE
FALSE
A neuron's response is based on whether the net input is excitatory or inhibitory. If EPSPs override the IPSPs,
threshold may be reached and set off an action potential
then they inhibit the neuron from firing
A neuron's response is based on whether the net input is excitatory or inhibitory. If IPSPs prevail over EPSPs,
threshold may be reached and set off an action potential
then they inhibit the neuron from firing
Summation is
the process of adding up postsynaptic potentials and responding to their net effect, this occurs at the trigger zone
the process of adding up presynaptic potentials and responding to their net effect, this occurs at the axon zone
What are the two types of summation?
Temporal Summation
Spatial Summation
Occipital Summation
Frontal Summation
When does temporal summation occur?
occurs when a single synapse generates EPSPs so quick that each is generated before the previous one fades, allowing them to add up over time to a threshold voltage that triggers an action potential
occurs when EPSPs from several synapses add up to threshold at the axon hillock. Any one synapse may generate only a weak signal but several synapses acting together can bring the hillock to threshold. Presynaptic neurons collaborate to induce the postsynaptic neuron to fire
When does spatial summation occur?
occurs when a single synapse generates EPSPs so quick that each is generated before the previous one fades, allowing them to add up over time to a threshold voltage that triggers an action potential
occurs when EPSPs from several synapses add up to threshold at the axon hillock. Any one synapse may generate only a weak signal but several synapses acting together can bring the hillock to threshold. Presynaptic neurons collaborate to induce the postsynaptic neuron to fire
The charge difference across the plasma membrane is called the
Resting Membrane Potential
Fast Track membrane potential
The Resting Membrane Potential (RMP) results from 3 factors:
the diffusion of ions down their concentration gradient through the membrane
selective permeability of the membrane, allowing some ions to pass more easily than others,
the electrical attraction of cations and anions to each other
