perisarc

The white pulp comprise the periaterial lymphatic sheath (PALS) and periellipsoidal lymphatic sheath (PELS), the latter being dominent and its lymphocytes being denser.

脾脏被膜较薄，小梁少而细，实质由白髓和红髓相间排列组成，前者包括精球周围淋巴鞘（ＰＥＬＳ）和动脉周围淋巴鞘（ＰＡＬＳ），未见淋巴小结。