This is a specimen of the penis of a monkey. The highly folded skin consists of a thin epidermis showing relatively little keratinization and a dermis . Immediately beneath the lamina on the dorsal surface locate the large dorsal artery and vein. The artery has an even muscularis, while the vein lacks a continuous muscularis and appears as a large irregular opening.

Locate the paired corpora cavernosa partially separated by the pectiniform septum. On the ventral side of the organ, locate the single corpus spongiosum containing the penile urethra. What type of epithelium lines the urethral lumen?

Note the presence of any intraepithelial glands or glands of Littre in the corpus spongiosum near the luminal epithelium of the urethra. These glands secrete a lubricating mucus into the urethral lumen.

Note the sheath of dense connective tissue (tunica albuginea) surrounding the three corpora and compare their thicknesses. Examine the structure of the erectile tissue within the corpora cavernosa. When the helicine arteries dilate, they increase blood flow into the venous channels that are surrounded by dense connective tissue septa containing some smooth muscle fill with blood. Observe the deep arteries lying close to the pectiniform septa and their branches, the helicine arteries. Review the role played by the dorsal vessels, the tunica albuginea, and the helicine arteries in the erection of the penis.

REFERENCES: Gartner, pp. 374- 375Ross, p. 665 DiFiore, p. 290 - 291 Wheater, p. 333 - 334