Inside Our Beautiful Brain: Neurons and Neurotransmission

Vocabulary flashcards covering the anatomy of neurons, neural communication, brain growth, damage-related conditions, and specific neurotransmitters and neurohormones.

Neuron

The fundamental building block of the brain and nervous system, a cell responsible for relaying information throughout the body in the form of electrochemical signals.

Dendrites

Branch-like extensions at the front end of a neuron that receive neurotransmitters from other neurons via receptor sites.

Neurotransmitters

Chemical messengers released by the axon that travel across the synapse to the dendrites of neighbouring neurons.

Excitatory neurotransmitter

A type of neurotransmitter that increases the overall activity of a neuron, making it more likely to fire.

Inhibitory neurotransmitter

A type of neurotransmitter that decreases the overall activity of the neuron, making it less likely to fire.

Soma

The cell body and control centre of a neuron, containing its nucleus and DNA.

DNA

A molecule present in nearly all living things that carries the genetic information responsible for cell development and function.

Axon

A cable-like extension from the cell body of a neuron that sends messages to other neurons.

Myelin sheath

Fatty, white insulating tissue that surrounds the axons of neurons to increase the speed of message transmission.

Neural impulses

The electrochemical messages that travel along a neuron, typically at speeds of $70\text{ to }120\text{ metres per second}$.

Axon terminals

Branch-like extensions at the end of a neuron that release neurotransmitters across the synapse to be received by other neurons.

Synapse

The small gap between neurons across which messages must travel.

Neurological disease

Any disorder that affects the brain as well as the nerves found throughout the human body.

Multiple sclerosis (MS)

A neurological disease where the immune system mistakenly attacks the myelin sheath, producing scarring of the axon (sclerosis) and causing communication issues.

Idiopathic

Refers to any disease that is of uncertain or unknown origin.

Acquired brain injury

Damage to the brain resulting from an accident or blow to the head.

Brain plasticity

The brain’s ability to recover from damage, such as when a wounded neuron's axon seeks out new connections with other neurons.

Sprouting

The growth of additional dendrites during learning, which allows a neuron to make more connections.

Pruning

The death of synapses due to disuse of neurons, following the principle of 'use it or lose it'.

Grey matter

Part of the brain consisting of the cell bodies (soma) of neurons where major processes like thinking occur.

Cortex

The outer layer of the brain made up of grey matter.

White matter

Part of the brain containing the axons of neurons insulated by the fatty, white myelin sheath.

Glutamate

The most common excitatory neurotransmitter in the central nervous system, playing a large role in memory and learning.

Central nervous system

A subdivision of the human nervous system that contains the brain and spinal cord.

Aspartate

The second most common form of excitatory neurotransmitter, important for focus, concentration, and metabolism.

Acetylcholine

An excitatory neurotransmitter that causes muscles to contract and is essential for attention, memory, and clear thinking.

Motor neuron

A special type of neuron that carries messages for voluntary and involuntary motor movement from the brain through the body.

Gamma-aminobutyric acid (GABA)

The main inhibitory neurotransmitter in the nervous system that calms or quiets neural activity.

Neurohormone

A chemical substance able to act as both a neurotransmitter in the synapse and a hormone in the bloodstream.

Hormones

Chemical substances produced by glands that travel through the bloodstream to target areas.

Synaptic cleft

Another term for the synapse; the gap between neurons usually measuring less than $1\text{ micrometre}$.

Serotonin

A 'feel good' neurohormone produced in the brain and intestines that regulates mood, wellbeing, sleep, and the digestive system.

Melatonin

A special sleep hormone released at night to help feel sleepy and dropped in the morning to increase alertness.

Endorphin

A neurohormone that acts as a natural painkiller during times of pain or stress, such as after strenuous exercise.

Enkephalin

A specific type of endorphin that serves as a powerful natural opiate, thought to be stronger than morphine.

Dopamine

A neurohormone often called the 'reward' hormone, essential for memory, learning, motivation, and smooth motor movements.

Substantia nigra

An area in the centre of the brain containing specialised neurons that produce dopamine.