and   secretion   of   the   male   sex   hormone testosterone. Lying close to the superior pole of each testis is  the  EPIDIDYMIS,  a  ductal  system  that  collects and transmits sperm from the testes. SPERMATIC  CORDS The   two   spermatic   cords,   each   of   which suspends and supplies a testis, are formed by the ductus deferens, arteries, veins, lymphatics, and nerves,  bound  together DUCTUS DEFERENS The ductus deferens by  connective  tissue. (VAS DEFERENS) is a small tube that con- nects  the  epididymis  and  ejaculatory  duct.  It ascends as part of the spermatic cord through the inguinal canal into the pelvic cavity and transmits the  sperm  to  the  ejaculatory  duct. SEMINAL  VESICLES The seminal vesicles are two pouches that lie between  the  bladder  and  the  rectum.  They  secrete and store a fluid to be added to the secretion of the  testes  at  the  time  of  ejaculation. EJACULATORY  DUCT The  ductus  deferens  and  the  ducts  from  the seminal  vesicles  converge  to  form  the  short ejaculatory  duct  that  leads  into  the  prostatic urethra.   Its   function   is   the   transportation   of secretions. PENIS The  penis  is  composed  of  three  cylindrical bodies  of  spongy  cavernous  tissue,  bound  together by connective tissue and loosely covered by a layer of skin. Two of the bodies, the corpora cavernosa, lie  superiorly  side  by  side;  the  third  body,  the  cor- pus  spongiosum,  is  median,  lying  in  the  groove between the other two. The dilated distal end of the  corpus  spongiosum  is  known  as  the  glans penis.   The   cavernous   tissue   becomes   greatly distended  with  blood  during  sexual  excitement, causing  erection  of  the  penis.  The  loose  skin  of the  penis  folds  back  on  itself  at  the  distal  end, forming the prepuce, or foreskin, and covers the glans.  Frequently,  the  prepuce  is  surgically removed (circumcision) to prevent irritation and to facilitate cleanliness. 3-48 PROSTATE  GLAND The prostate gland is made of smooth muscle and  glandular  tissue  that  surrounds  the  first  part of the urethra. It resembles a chestnut in shape and size. It secretes an alkaline fluid to keep the sperm mobile and protect it from the acid secre- tions  of  the  female  vagina.  This  substance  is discharged   into   the   urethra   as   part   of   the ejaculate,  or  semen,  during  the  sexual  act. BULBOURETHRAL  GLANDS (COWPER’S  GLANDS) Cowper’s  glands  are  two  pea-sized  bodies,  one on either side of the membranous portion of the urethra,  the  excretory  ducts  of  which  open  into the urethra. They secrete a mucouslike alkaline fluid during the sexual act to provide lubrication. SEMEN Semen  is  composed  of  sperm  and  secretions from the seminal vesicles, prostate, and Cowper’s glands. It is discharged as the ejaculate during sex- ual intercourse. There are millions of sperm cells in the semen of each ejaculation, but only one is needed to fertilize the ovum. It is generally con- sidered  that  fertilization  of  the  ovum  occurs  while it is still in the uterine tube. Therefore, it is ap- parent that sperm cells can move actively in the seminal  fluid  deposited  in  the  vagina  and  through the layers of the secretion lining the uterus and the uterine tube. Although the prostate, seminal vesicles, and bulbourethral  glands  secrete  most  actively  during sexual  intercourse,  a  certain  amount  is  being formed  continuously.  During  periods  of  pro- longed   sexual   abstinence,   discharge   of   this accumulation  may  occur  during  sleep  as  a  noc- turnal  emission  or  “wet  dream.”  This  is  an  en- tirely  normal  condition  and  does  not  constitute a  harmful  or  disease  state;  on  the  other  hand, retention  of  these  secretions  in  no  way  impairs health or the mental state. At times, what appears to be semen may drip from the penis on straining to move bowels. This is the secretion of the prostate and seminal vesicles being  forced  out  by  the  increased  pressure  within the  abdominal  cavity  and  forceful  passage  of  feces through the rectum, which lies close to these struc- tures. This occurrence does not indicate disease or infection if urethral discharge is present only during  such  acts  of  straining.  Any  continuing discharge  should  be  examined  for  evidence  of infection.