Puberty is a time marked by many changes. During this time a young girl's body changes into a woman's body and a young boy's body changes into man's body. And going from childhood to adulthood without a road map can be pretty scary.
Take a walk down the hallways of a K-8 school and it is easy to tell the difference between a 1
grader and a 6
grader. The first thing many students would point out is the difference in height. Childhood is a huge period of growth and development, but it is during puberty that a child grows at a faster rate than they have ever grown before. Many children who have entered this growth spurt complain to their parents that the brand new sneakers they got just last month are already too small or the hip new jeans they got a few months ago are now "high-waters." This puberty growth spurt is just that, a period of extremely fast growth.
The puberty growth spurt can be broken up in several parts including the height spurt, weight spurt, and changes in shape of the face and body. Because so many aspects of the body are growing and developing during puberty it is extremely important to eat healthy and exercise. Nutrients and exercise are essential for the development of strong bones that will carry a child into adulthood. Lack of bone mass can lead to serious health problems later in life.
The height spurt begins at different ages depending on the child, but females typically hit this growth spurt earlier than their male peers. It is for this reason that middle school girls are often taller than middle school boys. However, males tend to have a longer growth spurt than females explaining why men are often taller than women. This puberty growth spurt lasts for a few years after which growth slows down again and then stops.
Girls grow on average two and a half inches per year, prior to puberty. During puberty a girl's growth can double to up to four inches per year. This growth spurt typically lasts about three years adding on average nine inches to a girl's height.
The first menstrual period often marks the sign that growth has slowed down to one or two inches each year. A girl will usually reach her full adult height one to three years after her first period.
As mentioned above, boys tend to start their height spurt later than girls. For girls a noticeable change in height is one of the first changes, and for boys it is one of the last, occurring two years after girls. Boys also grow about two and a half inches per year prior to puberty. Once puberty begins a boy can grow up to four inches per year. Boys typically add nine to eleven inches during their puberty growth spurt, which last three to four years. Boys continue to grow until they are about nineteen years old, but not as fast as before.
The basis for the height spurt is that bones in the lower part of the body, especially the legs grow longer. Some of the first bones to grow are in the feet. It's no surprise that the feet reach their adult size long before a person has reached their adult height. In middle school a child's feet often look too big for the rest of their body, but rest assured everything will eventually proportion out and the awkward phase of tripping over one's feet will pass.
Puberty is marked by a period of growth lengthwise and widthwise. The body tends to get heavier as it gets taller. This is in part due to the growth of internal organs, muscles, and bones. Boys increase their weight more during puberty than any other stage in their lives. A boy can gain twenty pounds or more in a single year during this time. The average total weight gain during this time is forty-five to fifty-five pounds. Much of this weight gain comes from muscles. Boys also go through a strength spurt during puberty as their muscles grow bigger and more of the hormone testosterone is produced.
Girls also tend to put additional weight on due to fat tissue that builds up in their hips. This weight spurt lasts about three years and then slows down. A girl typically gains forty-five pounds over the course of the puberty weight spurt.
There is nothing wrong with gaining weight during puberty and it's important that teens continue to get the proper vitamins, minerals, and proteins so the body can continue to grow. Many teens worry that they are putting on too much weight and try dieting, which can be extremely dangerous for their health. Bones need minerals like calcium and zinc to support growth. Vitamin D is also important because it brings calcium to the bones. Without these essential ingredients in the diet, bones can be weakened and growth may be stunted. In addition to a healthy diet exercise is important for a healthy body. Lack of exercise is one of the leading causes of obesity. Physical activity also helps to strengthen a growing heart and lungs. These two organs allow oxygen to be sent to all the cells in the body and increase energy levels.
Changing Body Type
There is a marked difference between the body of a baby and adult. During the growth spurt the proportions of the of body change. For example, the head of a baby is one-fourth of the height, while an adult head makes up one-eighth of the total height. Additionally, a baby's legs make up a small part of the height, while an adult's legs account for about half of the height. The face also undergoes some reconstruction as it lengthens and narrows.
Hair and Sweat
Hair begins to grow under the arms and in the pubic region during puberty. Boys also start to grow hair on their faces in the form of mustache, sideburns, whiskers, and beards.
Underarm hair tends to appear a year after pubic hair. Hair also darkens on the arms and legs. Many boys are excited and proud of their first hairs, marking their manliness.
Girls on the other hand feel pressure to remove this unwanted hair, shaving being one of the most popular methods.
There is no right or wrong answer as to what to do with the hair. It is best for students to have a conversation with their parent or guardian about their decision.
Sweat and oil glands also undergo some changes during puberty causing the body to develop body odor and trapped oil on the face is likely to result in pimples. Sweat glands are the body's natural air conditioning system. The skin is covered with millions of sweat glands; by releasing sweat, which is made up of 99% water, the glands prevent us from overheating. Once the water is on the skin it evaporates causing the body to cool down. It is during puberty that the amount of sweat released by these glands increase and in addition, sweat glands located on the underarms and public region become activated.
The activation of sweat glands in these new areas also causes a change in the smell of the body itself. Sweat alone does not cause an unpleasant smell. Bacteria that live on the skin break down the sweat that causes the odor. Skin bacteria particularly like dark, moist places like underarms and pubic regions. Although there is nothing wrong with sweating and the body odor that comes with it, there are several ways to keep your body feeling clean and fresh. Teenagers should wash daily, wear clean clothes, and perhaps choose a deodorant or antiperspirant.
Spots and Dots
Acne is the most commonly used term for common skin problems during puberty, including zits, pimples, whiteheads, and blackheads. These skin conditions are caused by oil glands, which become overly active during puberty. This excess oil becomes trapped under the skin and clogs pores. Acne is most commonly found on the face, chest, back and neck. Although these spots and dots are neither fun nor attractive there is light at the end of the tunnel. The best way to get rid of acne is by using over the counter products containing benzoyl peroxide and/or salicylic acid. Benzoyl peroxide fights the bacteria that cause acne and salicylic acid removes whiteheads and blackheads.
Sex Organ Changes
While the bones are busy growing during the puberty growth spurt so are the reproductive organs. A boy's testicles are held within a sac of skin known as the scrotum. During puberty the testicles become larger in size and the skin of scrotum gets longer and thinner allowing the testicles to hang lower. Doctors measure the size of the testicles using a tool called an orchidometer.
This instrument contains a series of egg-shaped ovals strung together. Each oval has a number, which tells its size based on its volume (measured in milliliters). The skin of the scrotum also becomes redder and darker in color. The penis also grows longer and wider during puberty. It is difficult to determine the size of the average soft penis because the size changes often. Fear, cold, or nerves can reduce blood inside the penis making it smaller in size by up to two inches. Relaxation or warmth can increase the size of the penis. It is thought though when erect the variations among sizes tend to disappear, as smaller penises grow more during an erection and larger penises grow less. It is estimated that most men's penises are between 5 ¼ and 6 ¾ inches when erect. And the angle at which the penis sticks out from the body can also vary.
A woman's vagina doubles in size to become three to five inches in length. The ovaries become the size and shape of an almond and the Fallopian tubes are three to four inches in length and the thickness of a spaghetti noodle. The shape and the position of the uterus change as well to prepare for childbirth. In childhood the uterus is shaped like a tube, but in adult it takes on the shape of an upside down pear. The uterus of a young girl is upright, while a woman's uterus is tilted forward.
This growth spurt of the reproductive organs is caused by the release of hormones, or chemical messengers, from the pituitary gland, located at the base of the brain. In fact, hormones are responsible for many of the changes that occur during puberty including pubic hair, acne, body odors, and the growth spurt.
In males, the pituitary gland releases a hormone that travels through the blood stream to the testicles. This hormone causes the testicles to produce another hormone called testosterone. Testosterone is responsible for growth of the penis, facial hair, pubic hair, body hair, and muscle tissue growth.
Although testosterone is called the male hormone, females also have it too, but only in small amounts.
In females, the pituitary gland releases a hormone that travel through the blood stream to the ovaries. This hormone causes the ovaries to make another hormone called estrogen. Estrogen, the female hormone, travels to different parts of the female body and causes breast development and fat tissue to deposit around the hips. While estrogen plays a large role in the changes that take place during puberty, estrogen is also responsible for the menstrual cycle. As more estrogen is made in the ovaries a developing ovum is released. The level of estrogen also rises in the bloodstream and in turn cause the uterus to develop new blood vessels it is this lining. Should a male sperm fertilize the woman's ovum, it is this lining will serve nutrients for the growing baby. If fertilization does not occur then the lining will be shed during menstruation. Another hormone, progesterone, is produced in the ovaries and it is this hormone which causes the uterus lining to remain thick, to nourish the growing baby, or breakdown and leave as menstrual flow. The drop in progesterone levels triggers the pituitary gland to start the cycle over again. Although a typical cycle lasts 28 days some cycles are longer or shorter.
Boys begin puberty at different ages. Some begin around the age of nine, while others don't begin until they are fourteen or fifteen. Much of this has to do with family backgrounds, as boys tend to take after their fathers and other men on their dad's side of the family. Although there is no exact time that a boy should begin puberty it is a good idea for boys who start puberty before they are nine to see a doctor. Similarly, boys who haven't started puberty by the age of fifteen should visit a physician. It is better to catch problems sooner, rather than later and doctors can help boys continue on the track to healthy development.
The most noticeable signs of puberty are the growth and development of a boys testicles and scrotum. These organs go through their own growth spurt during puberty, as mentioned above. Boys also begin to develop pubic hair during puberty. The first hairs are usually light in color and begin growing in the area where the penis joins the body. Over time they become darker and curly and grow above the penis, on the lower abdomen, and toward the thighs.
Figure 1. The five stages of genital development and the five stages of pubic hair growth. Illustration by: Michal Komorniczak (Poland)
Doctors divide the growth and development of the male sex organs into five main stages (See Figure 1).
Stage I: Childhood - The childhood stage occurs before puberty begins. Because the male sex organs are located outside the body they do grow a little bit with the rest of the body during childhood. Though his growth takes place over many years and most testicles remain less than 3 ml in size.
Stage II: Testicles and Scrotum Enlarge - Boys reach this stage at the start of puberty when the testicles and scrotum increase in size. These organs have their own growth spurt during puberty and they grow at a faster rate than ever before. Testicles are typically 4 ml or larger in size at this point. The penis however remains around the same size as it was during childhood. As the testicles grow the skin of the scrotum grows longer and thinner allowing the testicles to hang lower from the body. As the scrotum loosens it begins to look baggy and wrinkled and also appears red or dark in color. Most boys reach this stage between the ages of ten and twelve and remain in this stage for a year.
Stage III: The Penis Grows Longer - During this stage the penis increases in length. The testicles and scrotum also continue to grow. Most boys are between the ages of ten and fourteen when they reach this stage which can last anywhere from a few months to a year and a half.
Stage IV: The Penis Grows Wider - In the last stage the penis grew in length and it is this stage that the penis also grows in width. The tip of the penis, known as the glans, also becomes more developed. In addition, the testicles continue to grow and the scrotum hangs lower. Most boys begin this stage at either thirteen or fourteen years old and remain in it for six months to two years.
Stage V: Adult Stage - When a male reaches this stage he is no longer a boy, but instead, a sexually mature adult. At this point the testicles are fully grown and between 14 and 27 ml in size (about 1 ¾ inches long). The scrotum and penis are fully developed and deep in color. Most males reach this sexual adulthood when they are fourteen to sixteen years old.
Doctors also divide the growth of pubic hair into five stages. However, these stages do not always align with male genital growth (See Figure 1).
Stage I: Childhood - Prior to puberty there is no pubic hair. Any hair that is in the genital region is short, fine, and soft, a sharp contrast to pubic hair, which is curly, thick, and coarse.
Stage II: First Pubic Hairs Appear - The first pubic hair appears during this stage and they are usually straight and lack color. They are however longer than childhood hairs and grow around the area where the penis attaches to the body.
Stage III: Growth Continues - Pubic hair is curly, course, and dark in color during this phase. The hair also covers a larger area and may extend to the scrotum.
Stage IV: Almost Adult - The pubic hair now looks like adult hair and there is much more hair than the previous stage. The hair takes on a triangular shape, but it remains around the genitals.
Stage V: Adult - At the adult stage the pubic hair is coarse and curly. The hair also extends to the edge of the thighs and up towards the lower abdomen.
During puberty a boy's voice becomes lower and deeper. This change occurs because the vocal cords, held inside the larynx, grow thicker and longer, which changes the tone of the voice. Most boys experience this change around fourteen or fifteen year of age. As the larynx grows some boys experience high pitch cracks and squeaks.
Sexual stimulation causes the male penis to become erect. This stimulation can be physical or mental. Although erections are usually thought of in a sexual nature, during puberty erections can occur when a male isn't doing or thinking about anything sexual. Many men have erections while they sleep. During puberty the male body makes testosterone, which causes the penis to be particularly sensitive. The penis is filled with spongy erectile tissue, which resembles a mesh of tiny chambers. Normally, these chambers are empty and flat. However, during an erection, blood flows to the penis and fills these tiny chambers causing the spongy tissue to swell. This swollen tissue causes the penis to become hard, rise up, and stick out from the body. An erection usually goes away on it's own or after a man has ejaculated. Once blood flow returns to normal the excess blood trapped in the chambers can drain away and the penis can return to its soft state.
Girls' bodies go through many changes during puberty including the development of breasts, growth of pubic and underarm hair, increased height, and a curvier shape. Doctors have identified many explanations for why some girls begin the process of changing into a woman before others. Where one lives, what one eats, how much one weighs, and when one's mother started are some common explanations. For example, girls who live at higher altitudes tend to start puberty later. Also, young girls who are malnourished develop later than their peers. On the other hand, obese girls tend to begin puberty earlier than girls of average weight. Genetics plays an important role in puberty, as girls tend to follow in the footsteps of their female relatives.
There is also growing evidence that girls are beginning puberty at an earlier age. Ten and even twenty years ago girls began breast and pubic hair development around the age of eleven or twelve. Today, Caucasian girls are beginning at the age of ten and African-American girls are starting at ages eight and nine.
Doctors however, are not sure as to why the differences between racial groups exist. Most argue that these two groups of girls tend to start within a few months of each other, explaining the year difference. Although there isn't a "normal" time to begin puberty, girls who show signs before the age of six or seven and girls who do not show signs by their thirteenth or fourteenth birthday should consult a doctor. There could be nothing wrong with this early or late start, but it is always better to catch a medical issue sooner rather than later.
Breasts and Curves
During puberty a girl's body changes its shape. The breasts begin to swell and grow out from the chest and the hips and thighs widen out. With these new additions to the figure a child's body takes on the rounder, curvier shape of woman. The size of the pelvic bones increase and fat cells are deposited to give the hips cushion. These new additions will allow for a woman to bear a child later in life.
Each breast is made up of a nipple and an areola. Only the nipple is raised prior to breast development. But during puberty the breasts blossom and get ready for a time when they may need to produce milk after childbirth.
There are five main stages of breast development (See Figure 2):
Figure 2. The five stages of breast development and the five stages of pubic hair growth. Illustration by: Michal Komorniczak (Poland)
Stage I: Childhood - This stage classifies girls who have not yet entered puberty. The breasts are flat in this stage and only the nipples are raised above the body.
Stage II: Breast Buds Develop - A tiny, flat breast bud begins to form under each nipple. This breast bud contains tissues, fat, and milk glands. The areola also increases in width during Stage 2, which can begin as early as seven or as late as fourteen.
Stage III: Development Continues - The breast itself, as well as the nipples and areolas grow larger. The breasts take on the shape of adult breasts, but they are much smaller in size.
Stage IV: Nipple and Areola Form Mound - The areola and nipple form a separate mound on the breast during this stage. Breasts in this stage are pointy or cone-like. Most girls reach this stage between the ages of twelve and fourteen.
Stage V: Adult - The nipple and areola are no longer separated. At this point this point the breasts are fully developed, although some woman's breasts may continue to fluctuate in size. During pregnancy the breasts become enlarged, as milk glands get ready to produce milk to feed the baby.
Breasts come in all shapes and sizes. And women also vary greatly in their timing and rate of development. Girls' bodies develop at the right time for them. There isn't one "right age" for the body's development. And when a girl starts to develop has nothing to do with how big her breasts will become. It is common for breasts to be itchy, tender, sore, or painful at times during development. Sometimes breast feel lumpy and this is also completely normal. One breast may develop faster than the other causing breasts to look uneven. And finally, one or both of the nipples may point inward, called an inverted nipple.
Many girls experience their first sign of puberty when they see little hairs developing "down there." During puberty pubic hair begins to covers a woman's pelvic bone and takes on a triangular shape. Hair often becomes darker and color, coarser, and curlier over time. However, much of this depends on genetics. This hair is completely normal and there is no need to pluck the hair, as this is painful and it will just grow back. The hair also comes in a variety of colors and some women have more or less than others.
Just like breast development, pubic hair growth generally occurs in five stages (See Figure 2). It should be noted that although public hair growth is divided up into five stages it does not mean that a woman will be at the same stage of breast development and public hair growth. These stages do not always align.
Stage I: Childhood - In this stage there is a lack of pubic hair.
Stage II: First Pubic Hairs Appear - The first public hairs that appear are usually straight and fairly light in color. It is often found on the edges of the outer lips of the vulva. Most girls enter this stage between the ages of eight and eleven.
Stage III: Growth Extends to Mons - Pubic hair continues to grow on the outer lips, but it also begins to grow on the mons, a pad of fatty tissue on top the pubic bone. The hair also begins to darken and get curlier during this stage.
Stage IV: Growth Continues - Pubic hair continues to cover more space in the pelvic region. A triangular shape begins to take shape and the hair is now dark, curly, and coarse.
Stage V: Adult - At the adult stage the pubic hair touches the edges of the inner thigh and forms a noticeable triangle. The hair might also grow up towards the stomach or onto the thighs.
In addition to noticeable changes taking place on the outside there are also some special things going on inside the body. The sex organs inside the body, called the reproductive organs. Two of the biggest changes that take place during puberty are the first ovulation and the first menstrual period. The first period called menarche tends to occur for most girls when they are in Stage 3 or 4 of breast development and/or in Stage 3 or 4 of pubic hair growth. Menstruation generally occurs two weeks after ovulation and this cycle is referred to as the menstrual cycle. Young girls often menstruate without ovulating, as it takes several months for the cycle to become regular. Once regular, this cycle occurs once a month and continues into late adulthood. The only time a woman doesn't ovulate is when she is pregnant.
Note: This unit is designed to supplement the New Haven 7
Grade Science Curriculum. The current curriculum covers the roles of the female reproductive organs (including the ovaries, Fallopian tubes, uterus, uterine lining, cervix, cervical canal, and vagina) and the male reproductive organs (including the testicles, scrotum, testicles, epididymis, sperm ducts, seminal vesicles, ejaculatory ducts, prostate, Cowper's glands, penis, urethra, and urinary opening). As a result, background material on these topics has been omitted from this unit. Background material on how people reproduce (including, fertilization, pregnancy, and birth) has also been omitted because it is covered in the reproductive portion of the New Haven curriculum.