Puberty and hormones!

Thanks for putting up with my hiatus last week. The move went well, even with an unexpected new kitty to bring along.  Just a reminder that I'm not going to be posting next Friday either, as it's my BFF's wedding.

So, now, onto today's post topic: puberty and the hormones that cause it.

Hormones are, at their most basic level, chemical signals from one part of your body that tell another part of your body to do something. Organs, glands, and even individual cells can produce hormones, and these hormones can have any effect from changing your metabolism to signalling fight-or-flight response to causing mood swings.  They're the little buggers responsible for PMS (and the menstrual cycle in general), growth spurts, and of course puberty.

Puberty is a progression of physical changes in which a child's body matures into an adult body, capable of reproduction.  Most girls hit puberty between ages 10 and 12, and finish it between 15 and 17.  Within this window, a girl will start menstruating and develop breasts and pubic hair, as well as experience growth spurts and the hardening of the long bones (like the femur in your thigh).

The onset of puberty is signaled by an increased production of a hormone called gonadotropin-releasing hormone (GnRH), which is responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland.

Basically, a part of your brain called the hypothalamus releases a hormone (GnRH) that tells your pituitary gland to make other hormones (FSH and LH).  These two hormones zip straight to your ovaries and tell them to get started producing estrogen and progesterone.  A specific form of estrogen called estradiol is the dominant hormone in female puberty, and it promotes the growth of the breasts and utuerus.  FSH also tells your ovaries to kick it into gear, causing the maturation of the little follicles inside that will eventually release ovum during ovulation.

The first sign that puberty has started is breast development, which starts around 10.5 years old on average. A hard, tender lump will develop right under the areola and over the next 1.5-2 years will slowly approach their mature size and shape; that starter lump will generally fade back into the rest of the breast tissue at the end of this development.  The areola will also grow in size and darken in color, and the nipple - which is typically an "innie" in children - will change to an "outie."

Another early sign of puberty is the development of pubic hair, which occurs right around the same time, or sometimes even slightly before, the breasts start to grow.  The first pubic hairs usually grow on the labia and then spread up and over the mons pubis, eventually forming the "pubic triangle," and often grows on the top of the inner thighs and close to the abdomen as well.

Next, your lady bits start changing.  The walls of your vagina will go from a bright red to a duller pink, and will also thicken a bit.  Vaginal secretions will change in order to maintain the pH balance - which keeps all the naturally occurring microbes there happy and healthy and fighting infections.  The labia majora and minora will also grow and change in color; the clitoris will grow as well. Shortly after breast development begins, the uterus, ovaries, and ovary follicles increase in size as they prepare to start menstruation.  They reach full functioning size in about 2 years, which is when a girl will typically experience menarchy - that is, her first period... which is fun.

What, wasn't everyone's like this? No? Okay then...

Anywhere between ages 8 and 16 is normal for a girl to start her period, and the length of the menstrual cycle will be unpredictable for the first few years.  Just because you start having your period doesn't necessarily mean you're ovulating - 80% of girls don't actually ovulate for the first year of cycles, 50% for the first three years, and 10% for the first 6 years.  The full nitty-gritty details of menstruation will be covered in the next post (June 7).

Another delightful change in puberty is the shift in body proportion and body fat distribution.  Rising levels of estrogen cause the shape of the pelvic bone to change, widening the hips (which makes a wider birth canal).  Fat tissue rises to a higher percentage than that of males (about 6% more), popping up in the breasts, thighs, hips, butt, pubic mound, and upper arms. This higher level of fat is essential for maintaining and regulating the amounts of hormones needed for the menstrual cycle, which is why girls with low body fat and low weight tend to have more irregular periods.  Those same hormones that regulate the mentsrual cycle are also necessary for bone development, which is why irregular periods correlate highly with osteoporosis (weak and brittle bones).

Self-disclosure time: I'm in recovery from anorexia nervosa.  From age 16 to about 23, I was deeply engrossed in my eating disorder and greatly underweight.  Even on birth control, I had extremely irregular periods, often going 6 months or more without one.  Because of this, I have osteoporosis and osteopenia (which is basically pre-osteoporisis) despite being only in my late 20s.  I've been in recovery for about 4 years now, at a healthy weight and with regular periods (still on birth control) and my bone health is slowly improving, but the damage I did to myself is very real.  Not just to my bones, but to my heart, reproductive system, and other vital organs, which all suffered due to prolonged malnutrition.  I guess what I'm trying to say with this is... be good to yourselves, ladies.

Okay, where was I? Right. The many wonderful changes caused by puberty.

All those hormones running through your body will also change the composition of your sweat, which can make it smell different... which is why oh so many teenagers really can benefit from proper use of soap and deodorant.  These hormones can also cause your skin to produce more oil, leading to zits and full-on acne.  For some of us, these zits and BO will mostly go away as puberty ends, but many times some degree of body odor and break-out will continue into adulthood. Thanks, hormones. Really, you shouldn't have.

Tune in in two weeks for a roadmap of menstruation.ho

Anatomy: BREASTS!

Breasts. Boobs, titties, tatas, melons, hooters, cans, jumblies, yabbos, balloons, fun bags, dirty pillows, sweater beasts, knockers. The Girls. The Twins. Thelma and Louise.

Whatever you call them, boobs are pretty great.  They're soft yet firm, bouncy, jiggly, and under a certain set of conditions, can produce fuel for periphery micro-humans.

So, let's start off by talking about development, anatomy, and function.  Human breasts are unique in that they are the only organ not present at birth - they develop instead during puberty, in response to rising levels of estrogen which direct fat deposits to the breasts and cause the milk ducts to grow.  This is also the stage in which the nipple and areola (the dark area of skin around the nipple) enlarge. After menstruation begins, the breasts enter a second stage of development in response to progesterone, which results in maturation of the milk glands (or lobules). The breast doesn't grow as much during this second stage as in the first, but is important later to make lactation possible.

Image courtesy of dentalarticles.com

1. Chest Wall, which separates the chest cavity (containing all the important organs) from the muscle layer above it.

2. Pectoral muscle aka "pecs." This thick, fan shaped muscle makes up the bulk of the chest muscle in males and sits right under the breast in females.

3. Lobules are hollow cavities which are lined with milk-secreting cells.  Each lobule has a duct which connects to the opening in the nipple. 

4. Nipple, the opening through which breast milk is delivered.

5. Areola, the circular area of colored skin surrounding the nipple.

6. Lactiferous ducts carry milk from the lobules to the nipple.

7. Fatty tissue that develops during puberty.

8. Skin layer which keeps all this awesome machinery from showing through.

The primary function of the breasts, as you can probably figure from the diagram above, is to produce milk for infants.  Human beings are mammals, a name which derives from the mammary gland - another name for all the milk-producing lobules present in the breast tissue.

The secondary function of the breasts it to be fabulous and sexy.

Oh River, you sexy thing.

But seriously.  Research suggests that women with larger breasts were viewed as more fertile and more capable of providing enough milk to produce healthy, strong offspring.  Additionally, the large deposits of fatty tissue in the breasts were essential for helping the human fetus develop its awesomely powerful brain.  So your boobs put the FUN in FUNCTIONAL.

Now, if the only breasts you've ever seen have been in movies, porn, and textbooks, you probably think there is only one type of "normal" breast - perky, round, sits high up on the chest, with pretty pink nipples and areolas about the size of a quarter.

NOPE.

Boobs come in a variety of shapes and sizes, and nipples and areolas can be any color from pink to purple to brown to black, and areolas can be so tiny they're invisible or they can cover the majority of the breast.  One breast may be bigger than the other, or they may sit low on the chest wall or hang down.  Nipples can be large and erect or small and flat. And y'know what? THESE ARE ALL NORMAL.

You may have been told by others, or have told yourself, that your boobs are weird or ugly or unattractive.  But they're not.  They're boobs, and they vary in shape and size and coloration the same as any other body part. Breasts change in size and shape through your lifetime, varying with changes in weight, hormones levels, your menstrual cycle, and of course if you choose to get pregnant and/or breastfeed.

The following images are from a wonderful website called the Normal Breast Gallery and show just a small sample of the variations in normal, healthy, beautiful breasts out there.  If you feel self-conscious about your breasts, I strongly encourage you to browse through that gallery and pay attention the enormous variety of forms out there and read the stories of other women and their struggles with body acceptance.

I truly believe that there is no such thing as an ugly boob. Of course, if your breasts are large enough that they cause you pain or discomfort, in which case you may which to speak to your doctor about breast reduction surgery.  The self esteem of many women is intricately tied to their bodies, and breasts play a large role in this, so I feel it's very important to work on appreciating your breasts no matter their size, color, or shape.  If you find that you cannot feel sexy or confident or feminine with your current breasts, there are many options for breast augmentation (enlargement, reshaping, etc) that you can discuss with your doctor. If you have a partner or a friend that says negative things about your breasts (or any part of your body), they probably don't deserve the privilege of seeing them. There is really only one thing your or anyone else should ever say to your breasts: 

Watch this until you believe it.

Seriously.

Next week: external genital anatomy including the mons pubis, pubic hair, and labia.  The clitoris and hymen will have their own posts.