Parts of a Neuron Flashcards
Neuron
o Specialized cell of the nervous system that is used to detect information, transmit information, and affect muscles and glands
Cell Body of Neuron
Soma
Parts of the Neuron
dendrites, nucleus, axon, myelin sheath, and terminal buttons
Dendrites
: receive messages from neighboring neurons
• Coated with receptors, so if chemical message nearby, dendrites will receive
Axon
conducts nerve impulse from the cell body to distance location
Myelin Sheath
increase speed and efficiency of nerve impulse
• Can misfire
• Experience with tall people growing very quickly(body adjusting)
Terminal Buttons
release chemical messages(neurotransmitters) onto neighboring dendrites
• Melatonin
• Serotonin
• Dopamine
• Glutenin
The Neural Impulse
o Electrochemical Transmission: communication from nerve cell to nerve cell
Electrical impulses
chemical messages
How does a neuron generate electricity?
Charged Particles called Ions
• Ions are atoms
• Sodium= Na+
• Potassium= K+
• Chloride- Cl-
Resting Membrane Potential
- negative 70mv
-difference in charge(voltage) of the cell membrane
-Na+ ions more attracted to negative charge inside - Na+ channels in axon membrane are closed
Action Potential
brief wave of positive electrical charge that sweeps down the axon
- threshold: minimum stimulation needed to open Na+ channels
- 3 Steps: Na+ rushes in, K+ repelled by postively charges Na+ ions, and K+ rushes out
Refractory period
o When so much potassium leaves, it cannot reproduce another action potential
After a neuron fires there is a period of time when it cannot fire again
All or None Law
if threshold is reached, a full action potential occurs; if threshold is not attained then no action potential will occur
Synaptic Transmission ;What happens when the action potential reaches the terminal buttons at the end of the neuron?
o Terminal buttons eject chemical called neurotransmitters into the synaptic gap
Synaptic Gap/Synapse
neuron passing through chemical or electrical signal to another neuron/target cell
Steps of Synaptic Transmission
- Action Potentia lreaches terminal buttons
- terminal buttons release neurotransmitters into the synapse
- neurotransmitters bind to dendrites(receptors on neighboring cells)
- dendrites(recieve message) to cell body to axon(conducts message) to terminal buttons(releases chemical message) to neurotransmitter release, then repreats
Synaptic vesicles
store neurotransmitters
Neuotransmitters
chemical messages
receptors
recieve neurotransmitters
Excitatory Synapse vs. Inhibitory Synapse
o Excitatory synapse: neuron is more likely to produce an action potential
o Inhibitory synapse: neuron is less likely to produce an action potential
o Need balance of both
How do we eliminate the neurotransmitter form the synphase after it has done its job?
o Two ways:
Enzymatic degradation: whole job is to destroy neurotransmitters
• Example: enzymes to destroy dopamine
Reuptake: releases neurotransmitters, then sucks it back up, recycled to be used later
