314 CHORD ATE ANATOMY 



passes medially to the ureter to enter the prostate gland where it becomes 

 the ductus ejaculatorius. As it approaches the prostate, it enlarges into 

 an ampulla and is joined by the duct of the seminal vesicle. Each 

 seminal vesicle is about two inches in length and three quarters of an 

 inch in diameter, formed by an elongated tube four to five inches long 

 coiled within a connective-tissue capsule. It secretes continuously an 

 alkaline mucous fluid. (Fig. 278) 



Prostate and Bulbo-urethral Glands. At the point where the ductus 

 ejaculatorius opens into the urethra, this passage is surrounded by a 

 conical mass of glandular and muscular tissue, the prostate gland. The 

 glandular portion of the prostate is formed by fifteen to thirty branched 

 tubular glands embedded in connective tissue containing compact masses 

 of smooth muscle fibers. The development of the prostate shows that 

 it is a modified portion of the wall of the urethra. Its alkaline mucous 

 secretion, produced at times of sexual excitement, has a stimulating effect 

 upon the movement of spermatozoa. Characteristic albuminoid concre- 

 tions are formed in the alveoli of the gland. In later years of life these 

 concretions increase in size and number and become calcified, so that the 

 lumen of the urethra tends to become occluded by the pressure of the 

 prostate. Embedded in the prostate is a median pouch, the prostatic 

 utriculus or uterus masculinus, which opens by a median aperture near 

 the openings of the ejaculatory ducts. The utriculus is a rudiment of the 

 embryonic Mlillerian ducts which in the female become the uterus. 



The bulbo-urethral glands or Cowper's glands are tubulo-alveolar 

 glands less than half an inch in diameter, embedded in the connective 

 tissue of the urogenital diaphragm near the bulbus urethrae. Their 

 ducts open into the cavernous portion of the urethra. At times of sexual 

 excitement they secrete an alkaline mucous liquid. 



The Penis. The male urethra extends into the intromittent organ, 

 the penis. Thus in the male the urethra serves both as an excretory and 

 as a reproductive outlet. Three portions of the urethra are recognized, 

 prostatic, membranous, and cavernous portions. (Fig. 278) 



The body of the penis consists of three masses of erectile tissue, 

 paired corpora cavernosa penis and the unpaired corpus cavemosimi 

 urethrae. The latter enlarges at the root of the penis into a bulbus 

 urethrae and terminates at the extremity of the penis as a swollen mass 

 of erectile tissue, the glans penis. In its flaccid condition the glans is 

 covered by the foreskin or prepuce. The paired corpora cavernosa are 

 prolonged into the peritoneal region as far as the tuberosity of the ischium. 

 In this way they form the fixed portion of the penis, the crura penis. 

 To each criis is attached an erector muscle, the ischio-cavemosus. 



The nerves of the penis are several. Branches of the second, third 

 and fourth sacral (spinal) nerves are known as erector nerves since their 



