During childhood, spermatogonia divide only to increase their number. After puberty, each division produces one replacement cell called a(n) _____ and one _____, which is destined to change with each division, ultimately forming mature sperm.

3000+ review questions on anatomy and physiology. 

Anatomy refers to the internal and external structures of the body and their physical relationships, whereas physiology refers to the study of the functions of those structures.