neuro system Flashcards
The differences in sodium and potassium ion concentrations across the cell membrane are maintained by the _____?
Na+ K+ pump
The potential difference across a membrane at rest is called the ___?
resting membrane potential
f the resting membrane potential becomes more negative, the change is called ________?
hyperpolerization -acitalcholine hyperpolarizes the SA node
If the resting membrane becomes less negative, the change is called ___?
depolerization
A depolarization that is confined to a small area is called a(n) ___?
local/graded potential
A large depolarization that spreads or is propagated along the entire membrane surface without changing the magnitude of the depolarization is called a(n) ______?
action potential
Specialized structures called ________ are the sites where action potentials from one cell are able to produce action potentials in an adjacent cell.
synapse
Some synapses are electrical synapses in which adjacent cell membranes joined at specialized areas called ________ allow depolarization in one cell to spread to the adjacent cell.
gap jxns
A stimulus just strong enough to cause an action potential is called a(n) ________ stimulus.
threshold
Gap junctions and connexons are characteristic of ________ synapses.
electrical
Conduction of impulse in myelinated fibers is referred to as ______ conduction.
salutatory
A synapse where the axon of one neuron synapses with the axon of another neuron is called a(n) ________ synapse.
axo-axon
The process of combining local potentials to reach threshold is know as?
summation
The basic functional unit of the nervous system is the ________.
neuron
The nervous system can be divided on a functional basis into the ________ and the ________ nervous system.
centeral ; periferial
A neurotransmitter such as acetylcholine results in the opening of ________ gated channels.
lygan
When a neuron starts to depolarize _______ ions move into the cell.
Na+
The ________ is a modified sympathetic ganglion that does not give rise to postganglionic fibers but instead secretes hormones similar or identical to sympathetic postganglionic neurotransmitters in the blood
adrenal madula
The unidirectional propagation of action potentials away from the original site of activation is ensured by the ______?
refractory
The ______ is the site of action potential initiation in neurons?
initial segment
Summing of EPSPs occurring very close together in time as a result of repetitive firing of a single presynaptic input is known as __________
temperal
Summing of EPSPs occurring simultaneously from several different presynaptic inputs is known as _________
spacail submation
graded potential or action potential
Behaves in all-or-none fashion?
action potential
graded potential or action potential
decremental spread away from the original site
graded potential
