The pathogen was at some point able to get into the blood or tissues.

These tumors can cause problems by growing into nearby tissues.

It gets into the tissue and then it's very difficult to remove by washing.

Their energy determines how far they can penetrate into tissue.

Here cells increase in size, but are not differentiated into specific tissues.

They blend into the surrounding tissue and are fixed in position.

But if you went deep enough into the tissue, no scar ever healed completely.

They move out from the blood into tissues and organs upon infection or damage.

These cells are able to go into other tissues by growing into them.

They are often involved in teaching anatomy, and research into certain systems, organs, tissues or cells.