Astrocytes Astrocyte means "star cell," a name that refers to the shape of these cells. Astrocytes provide physical support to neurons and clean up debris within the brain. They produce some of the chemicals that neurons need to fulfill their functions. They help to control the chemical composition of the fluid surrounding neurons by actively taking up or releasing substances whose concentrations must be kept within critical levels. The somatic and dEmdritic membranes of neurons are largely surrounded by asltrocytes, and astrocytes are involved in providing nourishment to neurons. In addition, astrocytes function as "neuron glute" and help hold neurons in place. These cells also surround .and isolate synapses, limiting the dispersion of neurotransmitters that are released by the terminal buttons.