Page 798 - Atlas of Histology with Functional Correlations

FIGURE 20.4 | Peripheral Section of Testis

(Sectional View)

Each testis is enclosed in a thick, connective tissue capsule called tunica
albuginea (1), internal to which is a vascular layer of loose connective tissue

called tunica vasculosa (2, 8). The connective tissue from the tunica vasculosa
(2, 8) extends into the testis and forms the interstitial connective tissue (3, 12)
that surrounds, binds, and supports the seminiferous tubules (4, 6, 9). Extending

from the mediastinum testis (see Fig. 20.10) toward the tunica albuginea (1) are
thin fibrous septa (7, 10) (singular, septum) that divide the testis into
compartments called lobules containing one to four seminiferous tubules (4, 6,
9). The septa (7, 10) are not solid, allowing intercommunication between
lobules.

Within the interstitial connective tissue (3, 12) are blood vessels (13), loose
connective tissue cells, and clusters of endocrine interstitial cells (of Leydig) (5,
11) that secrete the male sex hormone testosterone.

The seminiferous tubules (4, 6, 9) are long, convoluted tubules that are

normally observed cut in transverse (4), longitudinal (6), or tangential (9) planes
of section. These tubules (4, 6, 9) are lined with a stratified epithelium called the
germinal epithelium (14) that contains two major cell types: the spermatogenic
cells that produce sperm and the supportive Sertoli cells that nourish them. The
germinal epithelium (14) rests on the basement membrane of the seminiferous

tubules (4, 6, 9) with its cells illustrated in greater detail in Figures 20.5 to 20.8.

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