Making the membrane potential less (-) or more (-)
Making the membrane potential more (-) or less (+)
Membrane potential returning to normal after depolarization
The constant membrane potential when a nerve or muscle cell is not displaying rapid changes in potential
2 types of ionic channels
V.G. & Leak
What type of channel is always open?
What gate(s) does a V.G. Na+ channel have?
Activation & Inactivation
The ball and chain gate is called the ____ gate
what gate(s) does a V.G. K+ channel have?
The ball and chain gate is made of
(sequence of ) amino acids
4 characteristics of A.P.'s
all-or-none, threshold, non-decremental, & refractory periods (2)
What are the 2 types of refractory periods in an A.P.?
Absolute & Relative
Graded potentials move through the cell how?
Where do graded potentials occur?
cell body or dendrite
where are A.P.'s generated?
What 2 factors determine the speed of an A.P.?
myelenation & diameter (of fiber)
What kind of conduction occurs in unmyelinated fibers?
what conduction occurs in myelinated fibers?
Myelin is composed primarily of what?
How do A.P.s travel in myelinated fibers?
node to node
At the peak of an A.P. V.G. ___ channels start to close and V.G. ___ channels start to open
whose plasma membrane contains Ptn receptors for binding with chemical messengers?
cell body & dendrite
What returns the ions to their original location eventually after an A.P. alters their concentration slightly?
Why don't A.P.'s occur at the Input Zone?
it has very few Na channels
what is the name of myelin fibers in the CNS?
what is the name of myelin fibers in the PNS?
What are the nerves running btwn the CNS and various regions of the body?
The _____ a fiber, the less it resists local currents
What type of myelin fiber can regenerate axons?
schwann cells (in the PNS)
what 3 structures can a neuron terminate on?
muscle gland or neuron
When a neuron terminates on a muscle or gland, it _____ the structure
innervates (or supplies)
What is a synapse?
junction btwn 2 neurons
An A.P. opens what on the presynaptic knob?
Ca V.G. channels
What type of channels are on the subsynaptic membrane?
where are the NTs stored?
What is the name of the portion of the postsynaptic membrane directly underlying the synaptic knob?
What opens the channels on the subsynaptic membrane?
What are the 2 types of synapses?
Excitatory & Inhibitory
Excitatory Synapses open what?
nonspecific cation channels
During an EPSP, which ions move
Na & K (simultaneously)
During an EPSP what ion moves in a greater number?
excitatory post synaptic potential
inhibitory post synaptic potential
During an IPSP, which ions become more permeable
K & Cl
During an IPSP, the membrane becomes ____ to bring to threshold
During an EPSP the membrane become ____ to bring to threshold
The slight hyperpolarization of the postsynaptic cell is called
The time is takes for an electrical signal in the presynaptic neuron to convert to the electrical signal in the postsynaptic neuron is referred to as...
EPSP & IPSP are both
The composite of all ESPSs & IPSPs occuring at the same time on a post synaptic neuron from all of its presynaptic neurons
grand post synaptic potential
The A.P. caused by a rapid, repetitive, excitatory persistent input from a single neuron
The sum of all ESPSs originating simultaneously from up to 50 different presynaptic inputs
What part of a neuron has the lowest threshold?
A reduction in the amount of NTs released from a presynaptic cell due to the innervation of a separate presynaptic axon terminal binding to its terminal receptor site
An increase in the amount of NTs released from a presynaptic cell due to the innervation of a separate presynaptic axon terminal binding to its terminal receptor site
When a given neuron has many other neurons synapsing on it
the branching of axon terminals so that a single cell synapses w/ and influences many other cells