Testis Start with slide 51. The outer border of the testis is demarcated by a thick band of dense collagenous connective tissue, the tunica albuginea . The tunica albuginea has a good many blood vessels running through it, including some rather large arteries. This is to be expected, since the inner portions of the testis require good circulation, and the blood supply has to come through the outer tunic. From the tunica albuginea, small septa subdivide the cavity of the testis into smaller compartments.
Septation is usually incomplete in domestic animals.
To see the tunica albuginea, click here. The bulk of the testicular tissue is the seminiferous tubules . The outer wall of each seminiferous tubule is a single layer of boundary tissue cells similar in some ways to smooth muscle. The contractions appear to be spontaneous, and not to involve any nervous stimulation. For a closeup view of the architecture of the tubules, click here.