What is the difference between grey and white matter in the brain?

Grey matter is greyish in colour because of the grey nuclei of cells and fills 40% of the brain, but consumes 94% of the oxygen.

White matter is whitish in colour because of myelin and fills 60% of the brain.

White matter is made up of long extending nerve fibers (axons) and connects various grey matter areas.

Grey matter is made up of neurons, dendrites, glial cells, synapses, and capillaries which are involved in muscle control, sensory perception, memory, emotions, speech, and self-control.

Grey matter contols how brain processing and cognition.

White matter controls how the brain functions and also controls temperature, blood pressure, heart rate.

Smokers loose grey matter at a greater rate than non-smokers.

The elderly with more grey matter have better cognitive function.

A US study has shown that there is an association in children between poverty and lower volume of grey matter.

Damage to white matter may be a sign of Alzheimers, even though Alzheimers is a grey matter disease.

Alcohol use may decrease white matter volume.

What is a synapse?

A synapse is a very small gap between two nerve cells (neuron). An electrical or chemical impulse triggers neurotransmitters to carry information across the synapse.

The word synapse is from two Greek words, "syn" and "haptein" meaning "together" and "to clasp" respectively.

When the connection between two neurons is strengthened, this results in the storage of information, which becomes memory.

What is the Blood-Brain Barrier (BBB)?

The BBB is a semi-permeable membrane (of glial cells) which protects the Central Nervous System (brain & spinal cord) from toxins and changes in blood composition.

The BBB can be broken down by high blood pressure, microwaves, hyperosmolitity, radiation, infection, trauma, inflammation, schema, and pressure.

BBB dysfunction can lead to neural damage. Diseases such as MS, encephalitis, stroke, or tumours can also damage the BBB.

The brain is metabolically one of the most active of all organs in the body. The brain does not store energy so it therefore needs a continuous supply of glucose and oxygen to meet it's energy requirements.