Reproductive System

Function

The female reproductive system has two functions: The first is to produce egg cells, and the second is to protect and nourish the offspring until birth. The male reproductive system has one function, and it is to produce and deposit sperm.

Spermatogenesis

Spermatogenesis is the process by which the male gametes, called sperm, are created. The male testes have tiny tubules containing diploid cells called spermatogonium that mature to become sperm. The basic function of spermatogenesis is to turn each one of the diploid spermatogonium into four haploid sperm cells. This quadrupling is accomplished through the meiotic cell division detailed in the last section. During interphase before meiosis I, the spermatogonium’s 46 single chromosomes are replicated to form 46 pairs of sister chromatids, which then exchange genetic material through synapsis before the first meiotic division. In meiosis II, the two daughter cells go through a second division to yield four cells containing a unique set of 23 single chromosomes that ultimately mature into four sperm cells. Starting at puberty, a male will produce literally millions of sperm every single day for the rest of his life.

Oogenesis

Just like spermatogenesis, oogenesis involves the formation of haploid cells from an original diploid cell, called a primary oocyte, through meiosis. The female ovaries contain the primary oocytes. There are two major differences between the male and female production of gametes. First of all, oogenesis only leads to the production of one final ovum, or egg cell, from each primary oocyte (in contrast to the four sperm that are generated from every spermatogonium). Of the four daughter cells that are produced when the primary oocyte divides meiotically, three come out much smaller than the fourth. (Egg cells must contain enough supplies to synthesize all the products needed by the developing embryo until the embryo implants into the uterine wall. Implantation does not occur until 7-10 days after fertilization. Thus, the unequal division of the cytoplasm ensures the egg has enough supplies for this time period.) These smaller cells, called polar bodies, eventually disintegrate, leaving only the larger ovum as the final product of oogenesis. The production of one egg cell via oogenesis normally occurs only once a month, from puberty to menopause.

Premenstrual Syndrome

PMS is a group of symptoms that occur in women, typically between ovulation and a period


Symptoms:


  • Tenderness or generalized lumpiness of the breasts.
  • A feeling of bloating caused by the retention of fluid.
  • Mood changes, including feeling tense, irritability, depression, and anxiety.
  • Tiredness.
  • Difficulty concentrating and making everyday decisions.
  • Headaches, including migraine.
  • Backache and muscle stiffness.
  • Disruption of normal sleep patterns.
  • Unusual food cravings.


Prevalence:


As many as 1 in 3 women experiences symptoms of premenstrual syndrome (PMS) as her period approaches. In up to 1 in 20 women, these symptoms may be severe enough to disrupt activities.


Treatment:


Certain nonsteroidal anti-inflammatory drugs, such as ibuprofen, can help to relieve headaches, backache, and muscle stiffness. Diuretic drugsmay help to relieve fluid retention, thereby relieving bloating and breast tenderness. Your doctor may also suggest hormone treatment, such as treatment with the combined oral contraceptive pill. If you have persistent psychological symptoms, such as depression, antidepressant drugs may be helpful. No treatment is consistently successful, but the symptoms can usually be relieved.

Cryptorchidism

Cryptorchidism is a condition in which one or both of the testes fail to descend from the abdomen into the scrotum.


Symptoms:


Not seeing or feeling a testicle where you would expect it to be in the scrotum is the main sign of an undescended testicle.


Prevalence:


Of 6935 neonates assessed at birth, 255 (3.7%) were found to be cryptorchid at birth. The rates were significantly elevated for low birth weight, preterm, small-for-gestational age, and twin neonates. The overall rate had declined to 1.0% by the 3-month assessment and 1.1% at the 1-year assessment. Although the rates at the 1-year assessment tended to be higher for low birth weight and preterm infants, no significant group differences were observed.


Treatment:


  • Surgery
  • Hormone Treatment
  • Saline Testicular Prostheses