Assertion: tonsil's cell | /r/CapableOf | form sheath
Facets:
value: around the capillaries
type: LOCATION
value: to form a barrier
type: PURPOSE
Source sentences:
text: Epithelial reticular cells sequester developing lymphocytes and form a sheath covering capillaries and lymphatic vessels.
text: The epithelial cells form a sheath around the capillaries, to form a barrier to the entry of antigenic material into the spaces between the epithelial cells in the reticular network.