[1][2] Tanycytes in adult mammals are found in the ventricular system, and the median eminence, a circumventricular organ.

The long processes extend through the layer of astrocytes to cross the median eminence and form end-feet on neuropil, and blood vessels near the portal perivascular space.

[1][3] Along the process from each tanycyte are some unusual protrusions as spikes, and swellings, and at their end feet are boutons or claws.

[4] A tanycyte has a single long basal process that crosses into the hypothalamic parenchyma to make contact with blood vessels and an array of neurons.

[5] Studies suggests that tanycyte cells bridge the gap between the central nervous system (CNS) via cerebrospinal fluid (CSF) to the hypophyseal portal blood.

[8][9] Tanycytes provide a link that is both structural and functional between the CSF and the perivascular space of the hypophyseal portal vessels.