Sertoli cells, a type of sustentacular cell in the seminiferous tubules, form which protective structure?

1. Sertoli cells surround developing sperm cells at all stages within the seminiferous tubules. 2. Tight junctions link adjacent Sertoli cells together. 3. This creates a barrier that keeps bloodborne substances away from developing germ cells, and prevents germ cell antigens from leaking into the blood. 4. This structure is called the blood-testis barrier. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 27 "The Reproductive System", p.1283 §Sertoli Cells_