neuron and neural firing

Neurons

Cells that receive, process, and transmit information to other cells; the building blocks of the nervous system.

Glial cells

Cells in the nervous system that support, nourish, and protect other neurons.

Reflexes

Automatic responses to stimuli, composed of a single sensory and motor neuron connected through the spine with an interneuron.

Sensory neurons

Afferent neurons that carry messages from sensory organs to the brain and spinal cord.

Motor neurons

Efferent neurons that transport messages away from the brain to muscles or organs.

Neural transmission

The process where chemicals in the body work as agonists (excite) or antagonists (inhibit) by amplifying or blocking the absorption of neurotransmitters.

Resting potential

The state of a neuron when it has a small negative charge, gaining energy from charged chemicals (ions).

Reuptake

The process by which neurotransmitters not absorbed by the dendrite are reabsorbed by the sending neuron.

Multiple Sclerosis

A condition characterized by the depletion of myelin in the nervous system.

Excitatory neurotransmitters

Chemicals that excite the next cell into firing.

Inhibitory neurotransmitters

Chemicals that retract cells from firing.

Interneurons

Neurons that relay messages between sensory neurons and motor neurons without direct contact.

Action potential

Information traveling down the axon in the form of an electrical charge that causes neurotransmitters to be released.

All-or-nothing principle

The principle stating that once action potential is released, it cannot be reversed.

Depolarization

The movement of action potential as it passes through the axon, changing from resting potential.

Refractory period

A brief recharging period after each action potential during which the neuron can prepare for another potential.

Threshold

The level of stimulation required to trigger a neural impulse.

Myasthenia gravis

A condition caused by antibodies that block receptors resulting in muscles not being able to contract.

Dopamine

A neurotransmitter that affects mood, emotion, and arousal; associated with schizophrenia and Parkinson's disease.

Serotonin

A neurotransmitter that affects mood, hunger, sleep, and arousal; associated with hallucinations and depression.

Norepinephrine

A neurotransmitter involved in arousal and alertness; associated with anxiety and depression.

GABA

A neurotransmitter that regulates sleep-wake cycles; associated with sleep disorders and Huntington's disease.

Endorphins

Neurotransmitters involved in pain control and stress reduction; associated with addiction and artificial highs.

Acetylcholine (ACh)

A neurotransmitter involved in learning and memory; associated with muscle spasms and Alzheimer's disease.

Agonists

Drugs that increase the action of a neurotransmitter.

Antagonists

Drugs that block the effect of a neurotransmitter.