|THE MALE REPRODUCTIVE SYSTEM
WHY IS THE SCROTUM ON THE OUTSIDE OF THE MALE BODY?
Sperm are produced in the testes located in the scrotum. Normal body temperature (98.6 degrees F or 37.0 degrees C) is too hot and is lethal to sperm, so the testes are located outside of the abdominal cavity where the temperature is about 2° C (3.6° F) lower. The testes are located in a sac called the scrotum. NOTE - A woman’s body temperature is lowest around the time of ovulation to help insure sperm live longer to reach the egg.
WHAT CAN CAUSE INFERTILITY IN MEN?
If a man takes too many long, very hot baths, this can reduce his sperm count. Undescended testes (testes are supposed to descend before birth) will cause sterility because their environment is too warm for sperm viability unless the problem can be surgically corrected.
WHAT IS THE EPIDIDYMIS?
From the testes, the sperm are transferred to the epididymis, which are coiled tubules also found within the scrotum that store sperm and are the site of their final maturation process.
WHAT IS A VASECTOMY?
In ejaculation, sperm are forced up into the vas deferens (plural = vasa deferentia). From the epididymis, the vas deferens goes up, around the front of, over the top of, and behind the bladder. A vasectomy (cutting the vas deferens) is a fairly simple, outpatient operation that involves making a small slit in each scrotum, cutting the vasa deferentia near where they begin, and tying off the cut ends to prevent sperm from leaving the scrotum. Because this is a relatively non-invasive procedure (as compared to doing the same to a woman’s oviducts), this is a popular method of permanent birth control once a couple has had all the children they desire. Couples should carefully weigh their options, because this (and the corresponding female procedure) is not designed to be a reversible operation.
WHAT IS SEMEN MADE OF?
The ends of the vasa deferentia, behind and slightly under the bladder, are called the ejaculatory ducts. The seminal vesicles are also located behind the bladder. Their secretions are about 60% of the total volume of the semen (sperm and associated fluid) and contain mucus, amino acids, fructose as the main energy source for the sperm, and prostaglandins to stimulate female uterine contractions to move the semen up into the uterus. The seminal vesicles empty into the ejaculatory ducts. The ejaculatory ducts then empty into the urethra (which also empties the urinary bladder).
WHERE AND WHAT IS THE PROSTATE GLAND?
The initial segment of the urethra is surrounded by the prostate gland. The prostate is the largest of the accessory glands and puts its secretions directly into the urethra. These secretions are alkaline to buffer any residual urine, which tends to be acidic, and the acidity of the woman’s vagina. The prostate needs a lot of zinc to function properly, and insufficient dietary zinc (as well as other causes) can lead to prostate enlargement, which potentially can constrict the urethra to the point of interferring with urination. Mild cases of prostate hypertrophy (enlargement) can often be treated by adding supplemental zinc to the man’s diet, but severe cases require surgical removal of portions of the prostate. This surgery, if not done very carefully can lead to problems with urination or sexual performance.
WHERE AND WHAT IS THE COWPER'S GLAND?
The bulbourethral glands or Cowper’s glands is the third of the accessory structures. These are a small pair of glands along the urethra below the prostate. Their fluid is secreted just before emission of the semen; therefore, it is thought that this fluid may serve as a lubricant for inserting the penis into the vagina, but because the volume of these secretions is very small, researchers are not completely sure of this function.
WHAT CAUSES AN ERECTION?
The urethra goes through the penis. In humans, the penis contains three cylinders of spongy, erectile tissue. During arousal, these become filled with blood from the arteries that supply them and the pressure seals off the veins that drain these areas causing an erection, which is necessary for insertion of the penis into the woman’s vagina. In a number of other animals, the penis also has a bone, the baculum, which helps to stiffen it. The head of the penis, the glans penis, is very sensitive to stimulation. In humans, as in other mammals, the glans is covered by the foreskin or prepuce, which may have been removed by circumcision. Medically, circumcision is not a necessity, but rather a cultural “tradition.” Males who have not been circumcised need to keep the area between the glans and the prepuce clean so bacteria and/or yeasts don’t start to grow on accumulated secretions, etc. There is some evidence that uncircumcised males who do not keep the glans/prepuce area clean are slightly more prone to penile cancer.
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