Chapter 19 Flashcards
(31 cards)
Membrane Potential
Difference in electrical charge across their plasma membranes
More negative inside & more positive outside
Resting Membrane Potential (RMP)
Membrane potential maintained by a nonconducting neutron’s plasma membrane
Inside (negative)
Outside (Positive)
(-70mV)
Depolarization
Membrane potential toward zero
More K+ diffuses out of the cell, the excess of positive ions outside the plasma membranes increase —increasing the magnitude of the membrane potential.
(-70)
Action Potential
Nerve impulse
An electrical fluctuation that travels along the surface of a neurons plasma membrane.
Threshold Potential
Magnitude of the local depolarization surpassed a limit
must reach threshold
Relative Refractory Period
Few milliseconds after the absolute refractory period— the time during which the membrane is repolarizing and restoring
Continuous Conduction
The action potential thus has moved from one point to the next continuously along the axon’s membrane
Saltatory Conduction
Thus the action potential seems to “leap” from node to node along the myelinated fibers
Impulse regeneration
Synapse
Place where signals are transmitted from one neuron (presynaptic neuron) to another neuron (postsynaptic neuron)
Synaptic Knob
Tiny bulge at the end of neutron’s axon
Synaptic Cleft
Tiny space between a synaptic knob and the plasma membrane
Short-term Memories
Lasting only a few seconds or minutes
Intermediate Long Term Memories
Last from minutes to weeks.
Long-Term Memories
Memories needed for learning anatomy & psychology
Last for months or years.
Neurotransmitters
Two major functional classification:
1) excitatory neurotransmitters
2) inhibitory neurotransmitters
Class I (Acetylcholine-ACh)
Neurotransmitters
Class of its own
Has a chemical structure unique among neurotransmitters
Class II (Amines)
Neurotransmitters are synthesized from amino acid molecules
Ex. Tyrosine, tryptophan, or histidine
Catecholamine
Subclass: dopamine, epinephrine and norepinephrine
Amino Acid Glutamate
(Glutamic acid) is responsible for up to 75% of the excitatory signals in the brain.
Convergence
Occur when more than one presynaptic axon synapses with a single postsynaptic neuron
Synapses come together
Divergence
Occurs when a single presynaptic axon synapses with many different postsynaptic neurons
Synapses spread out
Autism Spectrum Disorder (ASD)
May involve synaptic malfunctions
Group of neurological disorders characterized by various combinations and severity of difficulties in social interactions, verbal and nonverbal communication, and repetitive behaviors.
Stroke
A common example is the destruction of neurons of the motor are of the cerebrum that resulted from a cerebrovasculae accident (CVA)
A hemorrhage from/cessation of blood flow through cerebral blood vessels
Lack oxygen is prolonged, the neurons die
Transient Ischemic attack (TIA)
Mini stroke
A temporary episode of blood disruption of brain
