Neuro Review Flashcards
Neuro Review
What is a Nervous System
Because we are not a plant, we are animals. We use the nervous system to process information about the environment and then respond with behavior. We do it with electricity.
Neuron
Brain cells are specialized to send electric signals.
Cell Body
Contains the nucleus and cellular organelles.
Dendrite
Branches from the cell body that receive signals.
Axon
Extension of the cell body to transmit signals to others.
Glial Cells
Most brain cells are not neurons but are glial cells. Glial cells help support neurons.
Where do neurons receive signals from?
Received at the dendrites and if enough signals are received, the neuron will send signals to other neurons.
Where are the signals sent down?
They are sent down the axon. Axons can be very long.
What are bundles of axons?
Nerves.
How do Neurons Communicate?
They communicate through the synapses, which are small gaps. They communicate by sending chemical messages called neurotransmitters.
What do neurotransmitters bind to?
They bind to receptors on the receiving neuron which is called the post-synaptic neuron.
Neurotransmitters can be …?
Excitatory- increase the rate of fire
Inhibitory- decrease the rate of fire
How do chemical messages turn into electric signals?
The action potential
How is an action potential triggered?
It is triggered by neurotransmitters in the synapse.
Action Potential
It is a temporary change in polarity. The neuron goes from being negatively charged to being positively charged.
Action potentials are “All or Nothing”- it either fires or doesn’t. The strength of the action potential is always the same.
What is the firs step of Action Potential?
Resting Potential. Maintaining equilibrium of positive and negative ions inside the outside of the cell. At rest, the inside has negative charge.
What is the second step of Action Potential?
Depolarization. Ion channels are active. Positive ions enter. Net charge becomes positive.
What is the third step of Action Potential?
Repolarization. Positive ions get kicked out and return to being negatively charged.
What is the 4th step of Action Potential?
Hyperpolarization. Temporarily too much negative charge. Unable to fire again until returning to resting potential.
Ion Channels
Each ion has specific ion channels to move in or out of the cell.
Positive ions
Sodium(Na+)
Potassium(K+)
Calcium(Ca+)
Negative Ions
Chlorine(Cl-)