Astrocytes – Tutorial
Please read Unit 5 – Introduction to Nervous System Tissues prior to completing the activities in this chapter.
Introduction to Astrocytes
Astrocytes (star cells) are the largest and most abundant type of neuroglial cell found in the central nervous system. As their name suggests, astrocytes have multiple long cellular extensions radiating out from a central cell body giving them a star-like or spider-like appearance. Most of the cellular extensions have widened tips known as “feet” that partially wrap around neurons or capillaries in the central nervous system.
One of the most important functions of astrocytes is they help form the blood brain barrier around capillaries in the central nervous system by partially wrapping their widened tips known as perivascular feet around capillaries. Collectively, the perivascular feet of many astrocytes completely surround a CNS capillary, creating an envelope that helps isolate circulating blood from the interstitial fluid of the CNS. The interwoven cellular extensions of astrocytes also create a vast mesh-like framework that provides physical support for neurons and other neuroglia in the CNS. Astrocytes also help stabilize damaged CNS tissue after injury and help guide the growth of neurons during embryonic development.
