THE SPERM TRACT AND THE PRODUCTION OF SEMEN

From its site of production in the testes, the sperm must travel through the sperm tract to reach the outside of the body. As it does so, the various components that make up the seminal fluid are added to the sperm. The sperm tract, illustrated in figure 3.7, consists of a number of ducts including the epididymis, the vas deferens, the ejaculatory duct, and the urethra. In addition, a number of glands that secrete various fluids join the sperm tract through a series of small ducts.

After being produced in the seminiferous tubules, the sperm are stored in the epididymis, which is a highly coiled, interconnected network of seminiferous tubules lying in the upper part of the testes. As the sperm mature in the epididymis, they become capable of movement as the neck of each sperm becomes flexible.

The vas deferens carries the sperm from the epididymis to the ejacu-latory duct. At this point, the ducts of the seminal vesicles join the sperm tract and provide a viscous, alkaline secretion containing fructose and prostaglandins. The fructose, a sugar, is a source of energy for the sperm; the prostaglandins stimulate uterine contractions and help the sperm move to the female's fallopian tubes where fertilization takes place. The prostate gland surrounds the ejaculatory duct at the place where it becomes the urethra. It secretes a milky fluid that aids in sperm motility. The fluid contains, among other things, a large concentration of bicarbonate ions that gives the semen its alkaline pH. The alkaline nature of the seminal vesicle fluid and the prostate gland fluid reduces the acidity present in the urinary system, which is joined to the sperm tract at the urethra. This is particularly important since sperm motility is adversely affected by an acidic environment. Finally, the bulbourethral glands (Cowper's glands) secrete a mucuslike substance that provides lubrication for the urethra.

The secretions just described are called seminal fluid, and the combination of sperm and seminal fluid is called semen. Since there frequently is confusion as to the distinction between sperm and semen, it is worthwhile to point out that while sperm are under the careful hormonal control previously described, the seminal fluid is produced by the body as needed and is not affected by hormonal levels. Also important is the fact that the semen contains an antibiotic substance called seminalplasmin. Were it not for seminalplasmin, seminal bacteria would almost always infect women's vaginas, making sexual intercourse a routine health hazard.

*30\205\8*

  improving wifi signal os x
Portuguese Italian Spanish English French German

 

QUICK CHECKLIST FOR EMERGENCY BIRTH


Sometimes labor progresses too rapidly for you to get to a hospital or birth center in time or for your caregiver to arrive for a home birth. In such an emergency, the following guidelines will help you achieve the best possible outcome. Review them now and keep a copy with you, just in case. Do these tasks yourself if you're alone. If you have a partner or helper with you, that person should assist you.

  1. Get help if possible. Call your partner, your caregiver, your hospital or birth center, and/or 911.
  2. Gather clean sheets, towels, paper towels, tissues, and extra clothing to be used during the birth and for your baby.
  3. Wash your hands if possible.
  4. Remove all clothing from your buttocks and vaginal area.
  5. Lie down on your side or sit leaning back. Make sure you're in a clean place with enough room for your baby to land.
  6. Put a sheet, towel, or some clothing under your buttocks.
  7. Try not to hold your breath if your body is pushing. Pant through each contraction until your baby is born.
  8. Wipe away mucus from your baby's nose and mouth.
  9. Dry your baby's head and body.
  10. Place your baby on your bare abdomen or chest.
  11. Cover your baby using cloths, towels, or clothing.
  12. Do not cut the cord.
  13. Breastfeed your baby if possible.
  14. If you're at home, await the birth of the placenta. (Place the placenta, still attached to the cord and your baby, nearby in a bowl, newspaper, or cloth.) If you're in a car, have someone else drive you and your baby to a hospital.
  15. Place towels or a pad between your legs to absorb the blood flow.
  16. Get medical help as soon as possible to check both you and your baby.

*30/292/5*