This is the organ where the two schemes in this atlas diverge most completely, and the divergence is a translation artefact rather than a disagreement. The Chinese term is pi, and what the tradition describes under it is the governing of transformation and transportation: the extraction of usable qi from food and drink and its distribution to the rest of the body, together with the holding of blood inside the vessels and the support of the flesh and the four limbs. An anatomist's spleen does none of that.
The pairing of pi with the English word spleen was made by nineteenth and twentieth century translators mapping the eleven organs onto the nearest available western names, and it has been criticised ever since. Some writers now capitalise the term, or leave it untranslated, so that a reader does not import the wrong anatomy.
Within its own system the Spleen is one of the five zang, rules the Earth phase with the Stomach as its fu partner, and takes late summer, worry or overthinking among the emotions, the mouth as its orifice, the flesh as its tissue, and the centre as its direction. With the Stomach it is called the root of the postnatal, the source of everything the body makes for itself after birth.
The western scheme gives the spleen to Saturn and to the melancholic humour, recorded separately. Neither account is a physiological claim and neither is guidance.