Which substance is secreted by the loop of Henie?

A. Epididymis: The epididymis is where sperm mature and are stored. It is not cut during a vasectomy.

B. Tunica albuginea: This is the connective tissue surrounding the testis, not part of the sperm-carrying duct system.

C. Efferent ductules: These ducts transport sperm from the testis to the epididymis, but they are not cut during a vasectomy.

D. Ductus deferens: The ductus deferens (vas deferens) is the tube that carries sperm from the epididymis to the ejaculatory duct. It is cut and sealed during a vasectomy, preventing sperm from reaching the urethra.

A. Producing early induced proteins: While natural killer cells can produce cytokines, their primary function is not related to protein production.

B. Promoting opsonization of bacteria cells: Opsonization is primarily performed by antibodies and complement proteins, rather than natural killer cells.

C. Secreting signaling molecules: While natural killer cells do secrete signaling molecules (cytokines) to communicate with other immune cells, their main role is the direct destruction of infected cells.

D. Destroying virally infected cells: The primary function of natural killer cells is to recognize and eliminate virally infected cells and tumor cells, contributing to the innate immune response.