Simple reflex arc- the circuit from
sensory neuron to muscle response.
Doesn't need input from the brain
(bypases the CNS). Slower than
conduction along an axon and never
faster than 15m per second. When one
set of muscles become excited,
another becomes relaxed.
Temporal summation-
repeated stimuli within
a brief time have a
cummalative effect.
Spatial summation-
synapses have the
property of summation
of space. Synaptic
inputs from separate
locations combine
their effects on a
neuron.
ensures that a
sensory stimulus
stimulates neurons
enough to activate
them
Excitary postsynaptic potentials
(EPSP)- a graded depolarization and it
results from a flow of sodium ions into
the neuron.
If an EPSP doesn't
cause the cell to
reach it's threshold,
the depolarization
decays quickly.
If the ESPS occurs
twice, the second
will add to it
producing temporal
summation
(increased action
potential)
Inhibitory postsynaptic potentials
(IPSP)- occurs when synpatic input
selectively opens gates for potassium
ions to leave the cell for chloride ions to
enter the cell.
Produces a temporty
hyperpolarization of a
membrane (decreased
action potential)