Lecture 16: Nervous System Flashcards
Graded potentials
Travel short distances
Action potentials
Long and short distances. Much faster.
Membrane potential
Difference in charge across membrane
Resting membrane potential
Difference between in and outside of cell. -70 mV
Current
Flow of charged particles
Action potentials
Voltage from threshold to +30 mV
Threshold potential
-55 mV
All or none principle
Nerve impulse travels over entire axon or doesn’t happen at all
De polarizing phase
Gets more positive. At threshold the voltage gated Na+ channel is open. Na+ moves in and voltage rises to +30 mV.
Re polarizing phase
Na+ channels close. K+ channels open. K+ moves out and brings membrane potential back to resting.
Continuous conduction
Un Myelinated fibers. Wave of depolarizations travels down length of axon.
Saltatory conduction
Myelinated fibers. Impulse jumps between nodes of ranvier.
Post synaptic potential
Change in membrane potential of postsynaptic terminal of a chemical synapse.
Amino acids
Aspartate: hydrogen acceptor for ATP
Glutamate: excitatory
GABA: inhibitory
Glycine: spinal cord, limb reflexes
Biogenic amines
Norepinephrine: stress hormone
Epinephrine: adrenaline
Dopamine: cognitive alertness
Serotonin: well being