AP Psych Unit 1 (1.3) Part One: Neuron and Neural Firing

Neuron “Nerve Cell”

Specialized cell in the nervous system that receives and sends messages with electrochemical signals.

Neurotransmitters

Chemicals in the brain that carry messages from one person to another.

Glial Cells

Cells that provide physical support for the neurons to grow on and around (glue).

Dendrites “Antenna”

Part of neuron, branch-like extensions that receives electrical messages from other cells.

Receptor Sites

Receive signals, receptors sites are the lock that the neurotransmitter molecule fits into.

Soma “Life Support”

The cell body of the neuron that is responsible for maintaining the cell and keep the neuron functional (nucleus included).

Axon “Talker”

Fiber that extends from the cell body to the terminal endings, its job is to carry messages out to other cells.

Myelin Sheath

Layer of fatty substance produced by certain glial cells, wraps around the axon to protect the nerve fiber from damage, insulating sheath, speeds up the neural message.

Axon Terminals

Tips at the end of the axon, send signal to other neurons.

Terminal Buttons/Synaptic Knobs

End of the neuron.

Synapse “Contact Point”

Meeting point between neurons, at the end of the terminal button is a gap known as the synapse.

Synaptic Vesicles

Store various neurotransmitters (chemicals) that are released at the synapse.

Synaptic Cleft or Gap

Less than a millionth of an inch wide.

Neural Transmission

Process by which chemical signal information travels through a neuron.

Electrochemical

Neurons send message electrochemically, meaning that chemicals cause an electrical signal inside the neurons.

Electrical Part

Happens inside the neuron itself.

Chemical Part

Takes place between the neurons (synapse).

Resting Potential

The imbalance between the inside and outside electrical charges of a neuron.

Step 1 of Neural Firing

The Selectively Permeable Membrane may allow certain positive ions to pass through.

Step 2 of Neural Firing

Receiving a message, the receptor site will trigger the axon to let in positively charged ions if it reaches threshold.

Threshold

Must reach a certain level of stimulation.

Step 3 of Neural Firing

Neuron sends information down axon, away from the cell body (Explosion of electrical activity).

Action Potential “Firing”

An electrical charge is created once stimulated enough by the +/- reaction, stopping resting potential (this is called depolarization).

All-or-None Principle

A neuron always fires at full strength, or not at all. The strength and speed of its action potential is always the same.

Step 4 of Neural Firing

The charge hits the axon terminals and tells them to release the chemical (neurotransmitters).

Step 5 of Neural Firing

The chemicals will cross the synaptic gap and stimulate the next neuron’s dendrites, and the signal continues.

Step 6 of Neural Firing - Reuptake

After the neurotransmitters stimulate the receptors on the receiving neuron, the chemicals are taken back up into the sending neuron to be used again.

Step 7 of Neural Firing - Refractory Period

A period of inactivity after a neuron has fired where positive ions used for electrical charge are flushed away.