What are those enumerations after the breadcrumb's :: called?

Hi folks,

If I look at urls like http://schema.org/Patient and
http://schema.org/PlasticSurgery, I see they have a '::' in their page's
breadcrumb.

Now I get the impression these are enumerations but why do the types before
the '::' have properties and the ones after the '::' don't?

Do they have any special name (like, Instance) and purpose, and is there
any documentation which explains these?

Lastly, how can I find all of them on schema.org, after all, they don't
show up on http://schema.org/docs/full.html, so is there another way to
find these?