You probably all know that the brain is made up of billions of brain cells called neurons. But how many of you have heard about other cells that reside in the brain? Have you ever heard tales depicting the deeds of the astrocytes?
Sticking the brain together
Astrocytes are one of a number of other cell types in the brain that are called the ‘neuroglia’, which literally means brain glue! They provide brain support in a number of ways.
These special cells are star shaped with multiple branches protruding from each arm; the branches reach out connecting to neurons and blood vessels. All these connections allow astrocytes to ensure the correct structural layout of the brain.
Astrocytes also help neurons in their day to day life, ensuring they have the correct blood and food supply as well as fine tuning the balance of ions (this includes electrolytes such as salt) that are crucial for neuronal electrical signalling. They can be viewed as astrocytic personal assistants to neurons: organising not only the meetings but keeping on top of the gas, water and electricity supplies, rent, ordering the groceries etc. Astrocytes are the personal assistants with the “connections” to supply a neuron’s every need.
More than a backing singer
The role in brain support and the personal assistant metaphor may give a “behind the scenes” impression of how astrocytes function. However, astrocytes are also intimately involved in the “front of house” key responsibility of neurons, that of transmitting electrical signals.
Astrocytes have been found to alter their star like branches when neurons fire a signal across the junction (called the synapse) with another neuron. In response to this neuronal signalling, astrocyte branches wrap around the synapse, effectively hugging the junction and so stabilising it. This stabilisation is necessary for longevity of the synapse, which is crucial for our learning and memory. This means that an astrocytic hug is necessary for brain function!
Astrocytes are much more useful for brain function, than the mouse cartoon Pinky ever is in the plots devised by his partner in crime -Brain!