Unit 1 Neurons

Neurons

a nerve cell: the basic building block of the nervous system

can form and disappear

cell body (soma)

The part of the neuron that contains the nucleus. The cell life-support center

Dendrite

a neuron bushy, branching extensions that receive and integrate messages, conducting impulses towards the cell body

axon

the segmented neuron extension that passes messages through its branches to other neurons or to muscles or glands

myelin sheath

a fatty tissue layer that insulates them and speeds their impulse. Helps with neural efficiency

glial cells

cells in the nervous system that support and protect neurons

Role: provide nutrients, insulate myelin sheath, guide neural connections, clean up waste after neurons send messages to one another

Synapse

the junction between terminal axon tip of sending neuron

synaptic gap

where the neurotransmitters are sent through

Neural transmission

The process by which neurons communicate with each other through chemical or electrical signals

electrical

happens inside the neuron itself

Chemical

take places between the neurons

Threshold

the level of stimulation required to trigger an action potential

Action Potential

brief electrical impulse sent across the axon

All-or -nothing principle

states that when a neuron reaches it threshold the action potential will fire at full strength

Depolarization

when the inside of the neuron becomes less negative compared to the outside

Change in electrical charge triggers action potential

Refractory period

A brief period in which the neuron can not fire another action potential

Resting potential

when the neuron goes back to its neutral state (ready to reach next threshold)

Name the steps in neurotransmission

1) stimulate

2) threshold

3) Depolarization

4) action potenial

5) repolarization

6) refractory period

7) resting potenial

Reuptake

excess neurotransmitters are reabsorbed by the sending neuron

Agonist

molecule that increases neurotransmission action

Antagonist

molecule that inhibits or blocks neurotransmission action

Neural Signals can be

Excitatory or inhibitory

The excitatory impulses need to outnumber inhibitory impulses

in order to produce action potential