1st sem: Nerve and Synapse Flashcards
Distribution of Na+ channels in a neuron are greatest at the
nodes of Ranvier
Contains channels formed by hemichannels called, “connexons” and morphological correlate of electrical synapses?
Gap junction
it is a local hyperpolarization of the post synaptic membrane that can bring the neuron to its THRESHOLD POTENTIAL?
Excitatory post synaptic potential
Can occur when the same synapse is activated multiple times in rapid succession because axons can fire action potentials at rates over 100Hz?
Temporal summation
functional zone of a neuron that mainly involves AP generation?
ZONE II
distinguishes excitatory chemical synapses in the brain
Temporal summation and spatial summation onto the post synaptic cell increase the likelihood that a post synaptic action potential will be evoked
It controls pain and pleasure by blocking the neurotransmitter SUBSTANCE P which transmits pain impulses to the brain
ENDORPHIN
membrane conductance at resting state is greater with
K (POTASSIUM)
True about relative refractory period
The cell is able to fire a second AP but a stronger than normal stimulus intensity is required
The minimum intensity of a stimulus capable of immediate generation AP is
Threshold stimulus intensity
True regarding SALTATORY conduction
occurs in myelinated fibers
has slower velocity in COLD than in WARM
faster than non-saltatory conduction in nerve fibers with diameters around 10 micro meter
It is directly proportional to conduction velocity of an impulse
nerve diameter
sodium conductance
myelination
unmyelinated axons differ from myelinated axons in that they are
refractory for a longer period after excitation
The RMP of a nerve axon is essential for signal generation. Instantaneous elimination of the _____ would most RAPIDLY bring RMP close to O mV?
high membrane permeability of K+
Ion influx involved in neurotransmitter release in the pre-synaptic membrane
CALCIUM
The nicotinic receptor at the motor end plate for acetylcholine is an example of an ion channel that is ______
ligand-gated channel
TRUE of local potential
The amplitude of the response is proportional to the stimulus intensity
Neuron C responds to stimulation of Neuron A with a propagated AP only when Neuron B (which terminates only on Neuron C) is also simultaneously stimulated. What is the likely situation?
Neuron B releases an excitatory NT
Membrane depolarization in post synaptic terminal is due to
Sodium influx
NOT true when volley of impulses travelling in a pre-synaptic neuron?
The generation of at least 1 AP in the post-synaptic neuron
usual site where action potentials are generated because of its high concentration of necessary channels?
Axon hillock
TRUE when a nerve cell membrane is depolarized by 5 mV
Its permeability to Na+ increases
Na+ ions move into the cell to causes further depolarization
Chloride ions move inwards down their electrochemical gradient
Nerve fiber that is highly susceptible to conduction block by anesthesia
TYPE C
It is coupled to a G protein that initiates second messenger cascades that can affect ion channels
METABOTROPIC RECEPTORS
