LO2 What Are Neurons and Glial Cells

Neuron

A type of cell in the nervous system responsible for conveying information through electrical and chemical signals.

Glial Cell

Supportive cells in the nervous system that provide support, nutrition, protection, and other functions for neurons.

Resting Potential

The small negative charge of approximately -70 mV maintained by a neuron when it is not transmitting a signal.

Action Potential

A brief wave of positive electrical charge that travels down the axon when a neuron is sufficiently stimulated.

Synapse

The junction between the axon terminal of one neuron and the dendrite or cell body of another, through which neurotransmitters are released.

Dendrites

Branch-like structures extending from a neuron that receive signals from other neurons.

Axon

A long, cylindrical projection from the cell body of a neuron that transmits information away from the neuron.

Myelin Sheath

A fatty insulating layer that surrounds the axon, facilitating faster electrical signal transmission.

Neurotransmitter

Chemical messengers released by neurons that transmit signals across the synapse to other neurons or target cells.

Glutamate

The most prevalent neurotransmitter in the brain, involved in excitatory signaling and learning.

GABA (Gamma Aminobutyric Acid)

A neurotransmitter that inhibits neuronal firing, acting like the brain’s brake pedal.

Acetylcholine (ACh)

A neurotransmitter involved in muscle contraction, learning, memory, and attention.

Dendritic spine

Tiny protuberances on dendrites that increase surface area for synaptic contact and contribute to learning and memory.

Norepinephrine (Noradrenaline)

A neurotransmitter that is released during stress, affecting alertness and various physiological responses.

Dopamine

A neurotransmitter associated with voluntary movement, mood, attention, and reward processes.

Serotonin

A neurotransmitter involved in mood regulation, sleep, and learning, with low levels associated with depression.

Neuropeptides

Long chains of amino acids that function as neuromodulators, producing slower, longer-lasting effects than neurotransmitters.

Refractory Period

A brief period after an action potential during which a neuron cannot fire again.

Sodium-Potassium Pump

A mechanism in cell membranes that actively transports sodium out of the cell and potassium into the cell, crucial for maintaining resting potential.

Selective Permeability

A property of the cell membrane that allows certain ions and molecules to pass while restricting others.

Optogenetics

A technique that uses light to control neurons that have been genetically modified to express light-sensitive ion channels.