paolaroncaglia
commented
3 years ago @dosumis @emquardokus yes to making thymus lobule part_of some thymus lobe, based on:
- PMID:17067941 describes anatomy across rodents (mouse, rat, guinea pig): "Normal Anatomy The mammalian thymus is located (...). The thymus consists of two distinct lobes connected by a connective tissue isthmus. A thin connective tissue capsule surrounds each lobe and, in most species, gives rise to septae, that partially subdivide the thymus into interconnecting lobules of variable size and orientation (Figure 8A, B). There is no sublobulation in the mouse." => lobes may or may not be subdivided into lobules, but when lobules exist, they're always part of lobes
- A Google search for images of rat thymus (when lobules are visible, they're part of lobes) (rat, because that's the species where lobules but not lobes are mentioned in the taxon note)
- Semantics. "Lobule" means "small lobe" in Latin. If we accepted that lobules could exist without being part of lobes, how should lobules be defined? By size? By number? I.e. if lobulation is observed and the substructures are small enough/numerous enough, then we'd call them lobules even in absence of lobes?
- All lobules in Uberon are anatomically, if not semantically, part of lobes (lung, liver...), but 'lobule' itself is undefined, which doesn't help. In fact it has an editor note "todo - provide definition. Clearly distinguish between lobules, lobes and acinar parts of glands (see for example lobule of mammary gland)".
For thymus, I'll add the part_of on Monday unless anyone screams.
This is certainly true for humans. More research needed to ascertain whether this is safe more generally:
thymus lobule has taxon_notes "in the mouse, the lobes of the thymus are not subdivided into lobules but only in the central medulla and a peripheral cortex (i.e. there is no distinct sublobulation). In humans, the two thymus lobes are composed of many lobules of various sizes which contain follicles, each comprising a medulla and a cortex. in the rat, the thymus is partially subdivided into lobules separated by thin bands of connective tissue which are continuous with the thin connective tissue capsule.