Nervous System Cells- The Biology of Behavior

Lecture 3

Nervous system

complicit communicator network made of neurons

Neuron

specialized cells that transmit neural messages other than other neurons, glands and muscles

Dendrite

receives neural messages from other neurons

Cell body (soma)

houses DNA

Axon

thin tube that transmits messages

Glial cells (glia)

provides structure for neurons

Myelin sheath

specialized cells that are wrapped around the axon to help transmit messages

Action potential

electrical impulse that travels from the cell body to the end of the axe (neural firing)

Threshold

level of electrical charge needed to stimulate action potential

All or none response

the electric charge of the neuron reaches a certain threshold & it fires an action potential

• there are either more neurons or more frequent action potentials; no stronger/intensity of action potentials

Synapse

the junction between 2 neurons

• messages re transmitted across synapse via neurtransmitters

• when we think/learn something repeatedly it uses the same neurons

Neurotransmitters

chemical messengers that travel across synapse from sending neuron to receptors on recieving neuron

Reuptake

the sending neuron reabsorbs excess neurotransmitters

Excitatory signals

increase likelihood that neurons will fire

• brings the cell closer to firing threshold

Inhibitory signals

decrease likelihood that neurons will fire

• prevents overfilling (overstimulation & seizures)