Ovaries

Today, I tackle a body part upon which I consider myself to be somewhat of an expert. Had my left ovary behaved years ago, I would not be typing this today–and I would still have both ovaries. Speaking with other women, it becomes obvious very quickly that we tend to know very little about our ovaries.  Hopefully, I will shed some light on this for you today!

Where are the ovaries?  It’s safe to say we know they’re in our pelvis, but where exactly?  A good estimate is to make a triangle with with your index fingers and thumbs and place that over your pelvis with the index fingers pointing downward.  In the upper corners is about where your ovaries are.  (They tend to be a bit lower and more centralized than most assume they are.)  The ovaries are held in place by a network of ligaments which also attach to the uterus and Fallopian tubes.  The ovaries are not connected directly to the Fallopian tubes.  Many diagrams shows the fimbriae (the leafy looking parts on the far left and right below) of the Fallopian tubes as been directly adjacent to the ovaries, which leads many to believe that the ovaries are directly attached to them.  They are not.  (Read more about the relationship between the ovaries and the Fallopian tubes in the section about Fallopian tubes.)


The ovaries are, ironically, shaped like eggs but are smaller than the chicken eggs that one typically purchases at the grocery.  The ovaries are about the size of a walnut, are slightly pearl colored, and have bumpy, soft surfaces.  The ovaries are responsible for producing a variety of sex hormones.  At birth, the ovaries of a healthy baby girl contain between one and two million eggs.  By the time puberty begins, most of these have wasted away leaving about 300,000 eggs–plenty for the reproductive lifespan.  Thus, a woman has a finite number of eggs, but men have a different mechanism that continually makes sperm.  This is why women have “childbearing” years, but men can father children throughout their adult lives.

The eggs have a complicated lifespan before they are even released for potential fertilization.  The term “egg” is generic and refers to a single cell’s journey through maturation.  Before maturation, the egg is referred to as an oocyte.  Once it finishes maturing (see diagram below), it becomes an ovum and three polar bodies.  The polar bodies are actually inside of the ovum and serve to “fuel” the egg once it is fertilized continuing cell division and replication before it implants in the uterine lining (where it forms a network of blood vessels that forms the placenta and umbilical cord).

Each month, the ovaries usually release one mature egg (not one from each).  The ovaries are covered in cells called follicles and within each follicle is a single egg.  Once an egg is matured, the process of ovulation can begin.  During this time, the follicle that houses the mature egg expands and eventually ruptures forcing the egg outward.  This rupturing is completely normal–it would be abnormal for ovarian follicles to never rupture, and in fact some women can actually feel a quick pain when the rupture occurs.  The diagram below is an illustration of the ovulation process, beginning in the upper-left hand corner and going clockwise.


Following a woman’s “childbearing” years, the ovaries continue to play an important role.  For years, many doctors prescribed a surgery called a hysterectomy to remove the ovaries (as well as the uterus and Fallopian tubes) once a woman was finished having children.  This was performed to prevent cancer from developing.  However, we now know that ovarian cancer can actually develop anyway after the ovaries have been removed.  This is because the ovaries share tissue with the internal cavity that remains following a hysterectomy.  Leaving the ovaries intact provides a number of hormonal benefits throughout menopause that are difficult to replace.  Thus, the benefits of leaving the ovaries intact often outweigh the drawbacks.  (This is something that should be discussed with a physician, because each individual has a different medical history that will affect any such decision.)

There is a lot more that could be said about ovaries, but let’s save that for another day.  Hopefully this gives you a better understanding of how the ovaries work!

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Herpes and Hepatitis B

Herpes and Hepatitis B are two sexually transmitted diseases that are often confused with one another because of their similar names.   The similarities end there.  What are the differences between the two?  And what are the symptoms, the causes, and the treatments?

The technical name for herpes is herpes simplex and it is caused by one of two viruses:  herpes simplex virus 1 (HSV-1) or herpes simplex virus 2 (HSV-2).  (Pretty obvious names, right?)  HSV-1 causes oral sores commonly called cold sores (pictured below).  HSV-2 causes genital herpes, the dreaded sexually transmitted disease that about 1 in 7 adults in the United States currently have.  Herpes goes through cycles of being active and inactive (when sores are present or not present).  Genital herpes can be spread during both the active and inactive cycles, even when being treated.  Herpes has no cure and will last a lifetime if contracted.


Herpes is not a fatal disease (though it can be if passed between a mother and baby during childbirth) but it can be quite annoying and embarrassing.  There are treatments to help moderate the disease, but it is important to remember that herpes can always be spread even when it is in an inactive stage.  The treatments for herpes are anti-viral and the best choice for you can be determined by your physician.  There is currently no vaccination to prevent herpes, but there may be in the future.

Herpes is a disease that is quite easy to detect visually, unlike that other H-disease hepatitis B.  Hepatitis B (often shortened to hep-b) is also caused by a virus, called hepatitis B virus (HBV; pictured below).  Hep-b is a disease that affects a staggering number of people.  Over 2 billion people are believed to have the disease.  It is spread by the transmission of bodily fluids (notably through blood transfusions and sexual acts, as well as other ways).

Hepatitis B affects the liver by causing acute (short-term) and chronic (long-term) inflammation.  This can result in jaundice, cirrhosis, and sometimes liver cancer.  The earliest symptoms, preceding these maladies, can include nausea, vomiting, body aches, mild fever, and darker than usual urine.  These can be mistaken for other illnesses if testing is not carried out.  These early symptoms often go away on their own but the disease may still be present allowing for more damage to the liver and for it to be spread to others.

So, it is crucial to visit a physician in order to have a test (usually a blood test) performed to determine the exact nature of your illness.  Hep-b very often clears on its own in those who suffer from the acute version.  However, the acute version may develop into a longer course of chronic hep-b.  If this occurs, it can cause serious damage to the liver and may even result in death.  Young adults, children, and infants are much more likely to develop chronic hepatitis B from the acute disease.  Though a virus cannot be totally cured through medication, it can be slowed and inhibited from causing more damage.

Hep-b is a disease that can be protected against.  The best means of protection is by receiving the vaccination against it.  This offers long-term protection.  As in any sexual situation, it is always best to be as careful as possible and in this case a condom will greatly lower the risk of spreading the disease.

So, to sum up, herpes is associated with genital sores, is generally not fatal, and can never be cured.  Hepatitis B has few outward symptoms, can be fatal if not monitored, and can only be cured by the body’s natural virus-fighting processes.  So, if you’re worried at all about either of these diseases, please visit a doctor who can make sure that your issues are carefully dealt with.  Your and your sexual partner’s health rely on it.

Müllerian Ducts and Sex Differentiation

Something that has always stuck with me since Intro to Biology years ago was something my professor said: females are the prototypical human sex. In other words, we all start out as females in a sense. It is not until around the 8 week benchmark in fetal development that a fetus starts to develop distinct sex characteristics. Generally speaking, from the moment of fertilization the embryo has an innate genetic sex (XX in a female; XY in a male). However, if you were to see a fetus before the 8 week mark, you would see that the genitalia is undifferentiated between XX and XY. That means that a female fetus and a male fetus look the same between the legs, so to speak.

So, why is that?  Why do female and male genitalia not differentiate from the moment of fertilization?  And what causes the differentiation when it happens?  And what did that professor mean by saying that females are the prototypical humans?  Well, it all has to do with the Müllerian ducts and hormonal reactions during pregnancy.

The Müllerian ducts are a set canals in the urogenital region of an embryo (that is, where the urinary and genital structures develop).  Depending on which way sex differentiation goes, the Müllerian ducts develop into the Fallopian tubes, uterus, and upper part of the vagina or they will begin to disappear leaving only small vestigial remains.  (The male reproductive organs develop out of the adjacent Wolffian duct.  These ducts begin to disappear during sex differentiation in females.)  Here is a diagram:

For reference, here is a list of homologous human reproductive structures (for instance, before sex differentiation, the scrotum and the labia majora are one and the same).

It is around this 8 week period that hormones are released from within a male fetus from the testes (from cells called Sertoli cells).  This is called the anti-Müllerian hormone.  The chromosomes of a male fetus receive this hormone and react by impeding the development of the Müllerian ducts.  In a female fetus, the chromosomes do not exist so the Müllerian ducts continue to develop.  From time to time, the necessary chromosome to inhibit the development of the Müllerian ducts in the male are missing.  (Remember that human chromosomes are incredibly complex, so when DNA is being “written” sometimes it can make a “typo.”)  When this happens, the fetus continues to develop the Müllerian ducts.  So, the genetically male fetus begins to grow a uterus and sometimes other female reproductive structures.  Usually, the testicles do not descend but a penis will still be present because it does not develop from the Müllerian ducts.  This is one of the many complications of determining sex at birth.  It may not be immediately clear what the child’s sex is.  This is called Persistent Müllerian duct syndrome (PMDS) and can also result as a failure of the testes to ever secrete the hormone.

So, going back to the words of my professor, all humans begin as embryos with the same “feminine” appearing genitalia.  This is why he says, with glee, that females are the prototypical humans.  Keep in mind all that the ancient Greek philosophers argued (and Freud, for that matter) that men were the essential human form and that women are defective versions of males.  Turns out, that all men start out as women in a manner.  There is a lot more to be said on this topic, but I will stop here for now.  Use the information you have learned here to impress your friends and put any obnoxious men in their place.  Please feel free to leave comments and questions.

Diet and Gender Determination

I have been hearing and reading for some time now about the belief by some that a mother’s diet can help determine the gender of a fetus.  Generally, this possibility is rejected by scientists and physicians alike.  I too reject this notion–in general.  A British study performed in 2008 argues that “you are what your mother eats.”  In a nutshell, the study argues that women who eat more calorie-dense foods such as cereal are more likely to give birth to a boy.

In a recent string of articles, skeptics and supporters alike have issued responses to this new study.  A recent piece by NPR presented both sides of the issue, but tended to give enough of a shadow of doubt so that the British study remains credible.  However, an article on WebMD is more dismissive of this study.  One researcher interviewed for this article said that trying to influence the sex of an unborn baby has been “of enormous interest forever [and] if something as simple as eating cereal would have made any difference, we probably would have figured it out by now.”  A fertility specialist interviewed for the article added,”What we’ve learned about sex selection in the recent past is that it’s ultimately determined by the father,” although he adds that there may be some factors in the mother’s reproductive tract that may make it more likely for “girl” or “boy” sperm to meet the egg.

It should be pointed out that the impetus for the study was the research done in mammalian biology that indicates that the females of other species of mammals do bear more male offspring when resources are plentiful and/or the mother is high-ranking within the group.  Within the laboratory setting, there has been some evidence that nutrition does directly influence gender-based changes in rats.  However, within humans, there is still no hard evidence that indicates that diet, or anything other than the chance of sperm, influences the determination of gender.

Going back what the fertility specialist commenting in the WebMD article argued, it is probably of most interest and use to study what, if anything, affects the uterine-vaginal-fallopian environment that may prohibit or inhibit the promotion of sperm based their chromosomal contents.  On the surface, it appears unlikely that there is any way that vaginal conditions can differentiate between X-sperm and Y-sperm as there is no real structural or outward difference between X- and Y-sperm.  (Remember the blog entry on sperm.)

So, yet another purported way of predicting or influencing the gender of a baby that has cropped up but is being shot down by scientists.  (Another such proposed way of influencing the gender of the baby is the timing and positioning of sexual intercouse.)  Do you have any theories about this subject?  I would like to hear from you.  Other comments or questions?  My ears are open.

Hormonal Differences

If you are anything like me and read the medical headlines every day you have probably noticed in the past few weeks a spate of articles about how hormones can affect a person’s social behavior.  The first such article was a timely piece, considering the state of the economy, that argues that the length of a person’s ring finger in relation to his or her index finger is indicative of his or her responsiveness to testosterone in the womb, and thus this measure correlates with how well the person is suited to financial trading. (Oddly, the Washington Post categorizes this article under “Women’s Health.”)

Specifically, these researchers say, the longer one’s ring finger in relation to the index finger the more likely it is that this person will be successful at financial trading.  Scientists are hailing this as “completely new and novel in terms of showing how sex hormones impact the brain.”  (Though there have been other studies that argue that sex hormones in the womb influence sexual orientation and anorexia.)  The trials performed in this study only examined men.  While it is possible that this effect also influences such behavior in women, it is unlikely to affect women as often as men since women naturally have less testosterone than men.

However, another article came out on the heels of this study arguing that higher amounts of estrogen (as an effect from the womb) cause women to not only feel more attractive and be perceived as more attractive but also to cheat on their partners more often.  The study showed that women with high levels of estradiol, a type of estrogen, were more likely to “dress more provocatively and show more thrill-seeking behavior.”  Interestingly, the likelihood of cheating on a partner was shown to take the form of monogamous affairs rather than one-night stands.  These women with higher estradiol are generally more fertile and therefore are hypothesized to biologically be programmed to continually look for other, better mates.  One of the researchers said, “Our results are consistent with the possibility that highly fertile women are not easily satisfied by their long-term partners and are especially motivated to become acquainted with other, presumably more desirable, men.”

Prenatal hormones and their effects have been known for years to play a great role in sexual differentiation.  Levels of testosterone and other factors in the womb can contribute to an XY-karyotype (or genetic boy) being born as a phenotypical female (with the appearance of female genitalia).  Research is constantly discovering more along these lines, such as the perceived psychological differences between males and females (i. e., men are from Mars, women are from Venus), including cognitive performance.  In light of these discoveries, many people cling to the notion that many of these naturally occurring situations are, rather, a result of nurture (e. g., a woman who cheats on her partner does so because of the way she was reared).

So, what do you think about all of this?  I would love to hear any or all questions or comments.  Thanks!

Sperm

Sperm may seem an odd choice of subject for a “young woman’s guide to gynecology and obstetrics.”  But it is this last word, obstetrics, that makes sperm a good choice for an entry subject.  Arguably, without sperm, obstetrics would not exist.   This may not always be the case, but for the time being, each human pregnancy makes use of sperm somewhere in the process.  So, let’s talk about sperm, baby!

Sperm is the male counterpart to the female gamete, the ovum (or egg).  Technically, what we commonly refer to as a sperm should be considered more of a sperm cell called a spermatozoon (spermatozoa, plural).  Since virtually everyone refers to the spermatozoon as a sperm, I will continue to use the word sperm in its place.  The human sperm consists of, ostensibly, a head an a tail.  This simple-looking structure belies its key importance in creating life.  Stored within the sperm is a complex DNA code that will (usually)[1] determine the sex of the resultant child and influence its phenotypical appearance–short or tall, dark or light, thin or stout–and many other genetic factors.

Each sperm is about three micrometers at its widest and about fifty micrometers long.  The tail of the sperm powers it forward, almost like a propeller, at about 1 to 3 millimeters per minute.  The semen, the fluid in which sperm are expelled from the male, has a chemical balance that keeps the sperm mostly inert until it is neutralized by the acidic environment of a vagina.  The sperm, when entering the vagina, journey upward in search of an egg to fertilize.  If the sperm do find an egg they will attempt to penetrate the membrane.  A single  sperm will succeed in penetrating the egg and the fusion of the two begins the process of meiosis in which the DNA of the mother and the father are spliced together to form a new set of DNA.

At this point, the sperm has reached its goal and blends into the developing human.  However, the sperm has many variations and not all sperm conform to the usual model we have in mind.  Abnormal sperm are actually quite common and come in many varieties.  For example, there are sperm with two heads, two tails, both, neither, and various other extra and missing parts.  Most abnormally structured sperm do not pose a genetic complication or threat to a potential pregnancy.  Because of structural deficiencies these abnormal sperm are not likely to reach an egg in the first place.

In all, sperm are an interesting and integral part to creating life and without them, there would be little basis for obstetrics.  So, any time you are thinking about obstetrics keep in mind the “little swimmers” that help make it possible.  Comments, questions, otherwise?  Please bring them forward!

[1] I am careful to say that the sperm usually determines the sex of a child because certain genetic problems can preclude a child with XY sex chromosomes from developing male characteristics, including genitalia, thus the Y-sperm from the father in this case does not determine the sex of the child.

Vaginal Rejuvenation

While there are a myriad of possible gynecological surgeries, which ones do women elect to have performed?  In the past tubal ligation and varying degrees of hysterectomy have been the most popular elective gynecological surgeries.  In the 1990s, though, elective c-sections began to boom.  Recently, however, a growing movement has developed in backlash to the increased number of unnecessary c-sections in the United States–both voluntary and involuntary.  Now, there is a new trend towards cosmetic gynecological surgeries such as “vaginal rejuvenation” procedures.

What are currently the most popular “vaginal rejuvenation” surgeries?  Labiaplasties are rising in popularity.  A labiaplasty is a plastic surgery that involves tightening of loose labial folds or removal of extra tissue of the vulva.  After childbirth, with age, because of disease, or because of genetics women may have labia that they feel is large or perhaps too loose.  Surgeons can perform reductions of this tissue to make it smaller and/or tighter feeling.  These surgeries can now be done with the assistance of laser, which are meant to help the healing process.  The American College of Obstetricians and Gynecologists (ACOG) issued a statement in 2007 stating that there is no documentation of the efficacy and safety of such a procedure.  The risks include those inherent with any surgical procedure (clots, bad reaction to anesthesia, etc), botched outcome leading to further complications or surgeries, and the ring of scar tissue created causing issues with childbirth.  A woman with such scar tissue would be less likely to be able to deliver vaginally, and would face enormous complications if she did.  Young women have labiaplasties more often than older women, thus the concern for childbirth.

Other “vaginal rejuvenation” surgeries include hymenorrhaphy and vaginoplasty.  Hymenorrhaphy is rarer than labiaplasty and bears fewer risks.  It is a simpler surgery in which an already ruptured hymen is recreated in order for the woman to prove (or feign) virginity.  Vaginoplasties are much more invasive and dangerous.  A vaginoplasty is performed in order to tighten or reconstruct vaginal muscles.  Reasons for vaginoplasty can include disease, childbirth, or other trauma to the vagina.  However, many women now seek vaginoplasties because they feel it will increase their pleasure and sensitivity during sex.  As the ACOG points out, though, there is no evidence to support this assumption.  Vaginoplasties are also very common among males seeking gender reassignment surgeries, as a vagina can be created out of penile or scrotal tissue.  Most associations and societies of plastic and cosmetic surgeons do not yet count or keep track of the abovementioned plastic surgeries, or have only recently begun tracking them.  So it is difficult to say how many such surgeries are performed every year.  However, it is clear even from the basic figures that the numbers of these elective surgeries are increasing exponentially every year.  (One figure shows that about 600 were performed in 2005, 1,000 in 2006, and over 4,000 in 2007.)  It is a whole other topic to discuss the socio-psychological reasons why women choose such surgeries, but what do you think?  Would you ever be willing to go under the knife for such a procedure?  Other comments or questions?  Shoot!