(2.31)
Now that we've followed the course of spermataozoa and seminal fluid from the testis to the ejaculatory duct, we'll move on to look at the penis. There's more to the penis than meets the eye. The part of the penis that's seen externally is only about half of its overall length. The rest of it is hidden within the root of the scrotum, and back here in the perineum.
Along most of its length, the penis, seen here in cross-section, consists of three somewhat cylindrical masses of highly expandable tissue. On each side are the corpora cavernosa, the singular of which is corpus cavernosum.
The corpora cavernosa are the main erectile bodies of the penis. They're contained within a strong layer of fibrous tissue, the tunica albuginea. Within this there's a continuous space, intersected by an open network of fibromuscular tissue. The space is filled with blood: a little when the penis is flaccid, much more when it's erect.
The two corpora cavernosa are separated by an incomplete septum. Running along the underside of the penis is the corpus spongiosum which is continuous proximally with the bulb of the penis, and distally with the glans, as we'll see.
The urethra is contained within the corpus spongiosum. Like the corpora cavernosa, the corpus spongiosum consists mainly of expandable vascular tissue, but it remains soft during erection, while the corpora cavernosa become hard.
In the intact penis, the glans is covered by a retractable fold of skin, the prepuce or foreskin, which is often surgically removed in infancy. Here, the prepuce has been divided. The skin that lines the prepuce is continuous with the skin of the glans here, in the coronal sulcus. We can see the glans more clearly in this penis that's been circumcised. This is the glans.
To ...
(2.31)
Now that we've followed the course of spermataozoa and seminal fluid from the testis to the ejaculatory duct, we'll move on to look at the penis. There's more to the penis than meets the eye. The part of the penis that's seen externally is only about half of its overall length. The rest of it is hidden within the root of the scrotum, and back here in the perineum.
Along most of its length, the penis, seen here in cross-section, consists of three somewhat cylindrical masses of highly expandable tissue. On each side are the corpora cavernosa, the singular of which is corpus cavernosum.
The corpora cavernosa are the main erectile bodies of the penis. They're contained within a strong layer of fibrous tissue, the tunica albuginea. Within this there's a continuous space, intersected by an open network of fibromuscular tissue. The space is filled with blood: a little when the penis is flaccid, much more when it's erect.
The two corpora cavernosa are separated by an incomplete septum. Running along the underside of the penis is the corpus spongiosum which is continuous proximally with the bulb of the penis, and distally with the glans, as we'll see.
The urethra is contained within the corpus spongiosum. Like the corpora cavernosa, the corpus spongiosum consists mainly of expandable vascular tissue, but it remains soft during erection, while the corpora cavernosa become hard.
In the intact penis, the glans is covered by a retractable fold of skin, the prepuce or foreskin, which is often surgically removed in infancy. Here, the prepuce has been divided. The skin that lines the prepuce is continuous with the skin of the glans here, in the coronal sulcus. We can see the glans more clearly in this penis that's been circumcised. This is the glans.
To see its continuity with the corpus spongiosum we'll remove the skin and subcutaneous tissue. Here's the right corpus cavernosum. Here's the corpus spongiosum. The corpus spongiosum becomes continuous with the glans here. The two corpora cavernosa end bluntly, just behind the glans.