EXICITABLE TISSUE- NEURAL COMMUNICATION Flashcards
dendrites and cell body
Input zone:
Receives incoming signals from
other neurons (graded potentials)
axon hillock
Triggering zone:
Initiates action potentials
axon
conducting zone
conducts action potential
axon terminal
Output zone:
Releases neurotransmitter that
influences other cells
neurons generate two types of signal
- graded potential and action potential
graded potential
- short distance signal• Local changes in membrane potential
• Dependent on the strength and duration of
triggering event
– Stronger the stimulus → larger the
the magnitude of the graded potential.
– Longer the stimulus→ longer the graded
potential lasts.
• Propagate to adjacent areas (← or → direction)
– Local currents depolarise adjacent membrane areas,
spreading the wave of depolarisation
• Die out over a short distance
– Serve as short-distance signals
graded potential occurs where and what do they cause and how do they spread
- occurs in dendrites and cell body
- causes gated ion to open mainly the Na gate
- spreads by passive current flow
if a graded potential is large enough it can trigger
an action potential
where does an action potential occur
in the axon
what is the action potential
the rapid change in electrical potential that parts of a nerve cell undergo when a nerve impulse is generated
threshold
critical potential the membrane must depolarise for an action potential to
occur
at -50Mv
action potential
Serve as long-distance signals
• If a graded potential is large enough to reach
threshold an action potential is initiated
depolarisation
the membrane becomes more positive than at a resting potential
repolarization
the membrane returns to resting potential after having been depolarized
