Puberty and girls
Puberty is a time when a girl's body changes so she can reproduce — that is, so she can have a baby. Menstruation, ovulation and the development of breasts are important changes for girls during puberty.
Menstruation
Menstruation is also known as a girl's period. Girls start to menstruate (or get their periods) during puberty. It usually happens around 12 months after the first physical signs of puberty but because puberty starts at a different time for each of us, the age at which a girl gets her period will vary. It normally begins at 10–14 years of age.
The menstrual cycle
A menstrual cycle is about 28 days in length, although the length of a cycle is different for each girl. It is controlled by the release of different hormones that regulate what happens in the cycle. The first day of a girl's period signals the start of her menstrual cycle. A ‘period’ is the shedding of the uterus lining, which is called the endometrium. The lining comes out as fluid through the vagina. This fluid is comprised of the lining of the uterus wall, blood and the unfertilised egg. Once the period is finished — that is, the bleeding stops — hormones direct the body to start building up the endometrium again. The endometrium builds up or thickens to house the egg if it is fertilised by a male's sperm.
A period usually lasts three to seven days. The length and heaviness of a period are different for each girl. Periods are irregular for most girls in the first year, but then settle into a fairly regular cycle. Some girls may experience abdominal pain and/or backache when they get their period or in the few days before, while others may experience only minor discomfort.
Hormones and the menstrual cycle
The menstrual cycle is controlled by the release of different types of hormones. Each hormone has a specific role to play. The menstrual cycle has four phases.
During the menstrual phase, the thickened lining of the uterus (endometrium), blood and the unfertilised egg flow from the uterus and out through the vagina. This phase is commonly referred to as a period
The follicular phase is the time between the first day of menstruation (period) and when ovulation occurs. During this phase, the pituitary gland releases follicle-stimulating hormone (FSH). This hormone stimulates the ovary to produce a number of follicles (approximately 5–20). In most cases, only one of these follicles will mature into an egg. Also at this time, the lining of the uterus begins to thicken again in preparation for possible fertilisation of an ovum and the resulting pregnancy. There is also a rise in levels of the female sex hormone oestrogen.
The ovulation phase occurs when the mature egg is released from the follicle on the surface of the ovary. Ovulation usually occurs in the middle of the menstrual cycle — that is, about day 14 of a 28-day menstrual cycle. As oestrogen levels rise during the follicular phase, the brain triggers the release of gonadotropin-releasing hormones (GnRH). This hormone prompts the pituitary gland to produce higher levels of luteinising hormone (LH) and FSH. Ovulation is triggered by high levels of LH. The egg moves from the follicle on the surface of the ovary down through the fallopian tube to the uterus. The life span of the egg is around 24 hours and unless it meets a sperm during this time, it will die.
The luteal phase is approximately two weeks in length. During this time, the ruptured follicle on the surface of the ovary changes into a structure called the corpus luteum. The corpus luteum starts to release the sex hormone progesterone and small amounts of oestrogen. These two hormones maintain the thickened lining of the uterus. If the ovum is not fertilised by sperm to create a pregnancy, the corpus luteum will die. This occurs around day 22 of a 28-day cycle. This causes the levels of progesterone and oestrogen to fall and the lining of the uterus to come away and flow with blood from the uterus through the vagina as a menstrual period.
Puberty and boys
Just as girls' bodies get ready to reproduce, boys experience physical changes that enable them to reproduce. The most obvious of these physical changes are an increase in size of the testes, scrotum and penis. It is during puberty that the male starts to produce sperm which, when mature, are capable of fertilising the female's ovum for conception.
Ejaculation
During puberty, boys experience their first ejaculation, which is a release of semen from the penis. Ejaculation usually occurs when a boy masturbates or when he has a nocturnal emission (wet dream). The epididymis is located at the back of the testes. It collects immature sperm from the testes. When the sperm mature, they are released into a tube called the vas deferens. The sperm travel up the vas deferens, where they mix with semen released by glands lining the vas deferens. They then travel through another tube called the urethra, which runs through the penis.
Puberty is a time when a girl's body changes so she can reproduce — that is, so she can have a baby. Menstruation, ovulation and the development of breasts are important changes for girls during puberty.
Menstruation
Menstruation is also known as a girl's period. Girls start to menstruate (or get their periods) during puberty. It usually happens around 12 months after the first physical signs of puberty but because puberty starts at a different time for each of us, the age at which a girl gets her period will vary. It normally begins at 10–14 years of age.
The menstrual cycle
A menstrual cycle is about 28 days in length, although the length of a cycle is different for each girl. It is controlled by the release of different hormones that regulate what happens in the cycle. The first day of a girl's period signals the start of her menstrual cycle. A ‘period’ is the shedding of the uterus lining, which is called the endometrium. The lining comes out as fluid through the vagina. This fluid is comprised of the lining of the uterus wall, blood and the unfertilised egg. Once the period is finished — that is, the bleeding stops — hormones direct the body to start building up the endometrium again. The endometrium builds up or thickens to house the egg if it is fertilised by a male's sperm.
A period usually lasts three to seven days. The length and heaviness of a period are different for each girl. Periods are irregular for most girls in the first year, but then settle into a fairly regular cycle. Some girls may experience abdominal pain and/or backache when they get their period or in the few days before, while others may experience only minor discomfort.
Hormones and the menstrual cycle
The menstrual cycle is controlled by the release of different types of hormones. Each hormone has a specific role to play. The menstrual cycle has four phases.
- The menstruation phase
- The follicular phase
- The ovulation phase
- The luteal phase
During the menstrual phase, the thickened lining of the uterus (endometrium), blood and the unfertilised egg flow from the uterus and out through the vagina. This phase is commonly referred to as a period
The follicular phase is the time between the first day of menstruation (period) and when ovulation occurs. During this phase, the pituitary gland releases follicle-stimulating hormone (FSH). This hormone stimulates the ovary to produce a number of follicles (approximately 5–20). In most cases, only one of these follicles will mature into an egg. Also at this time, the lining of the uterus begins to thicken again in preparation for possible fertilisation of an ovum and the resulting pregnancy. There is also a rise in levels of the female sex hormone oestrogen.
The ovulation phase occurs when the mature egg is released from the follicle on the surface of the ovary. Ovulation usually occurs in the middle of the menstrual cycle — that is, about day 14 of a 28-day menstrual cycle. As oestrogen levels rise during the follicular phase, the brain triggers the release of gonadotropin-releasing hormones (GnRH). This hormone prompts the pituitary gland to produce higher levels of luteinising hormone (LH) and FSH. Ovulation is triggered by high levels of LH. The egg moves from the follicle on the surface of the ovary down through the fallopian tube to the uterus. The life span of the egg is around 24 hours and unless it meets a sperm during this time, it will die.
The luteal phase is approximately two weeks in length. During this time, the ruptured follicle on the surface of the ovary changes into a structure called the corpus luteum. The corpus luteum starts to release the sex hormone progesterone and small amounts of oestrogen. These two hormones maintain the thickened lining of the uterus. If the ovum is not fertilised by sperm to create a pregnancy, the corpus luteum will die. This occurs around day 22 of a 28-day cycle. This causes the levels of progesterone and oestrogen to fall and the lining of the uterus to come away and flow with blood from the uterus through the vagina as a menstrual period.
Puberty and boys
Just as girls' bodies get ready to reproduce, boys experience physical changes that enable them to reproduce. The most obvious of these physical changes are an increase in size of the testes, scrotum and penis. It is during puberty that the male starts to produce sperm which, when mature, are capable of fertilising the female's ovum for conception.
Ejaculation
During puberty, boys experience their first ejaculation, which is a release of semen from the penis. Ejaculation usually occurs when a boy masturbates or when he has a nocturnal emission (wet dream). The epididymis is located at the back of the testes. It collects immature sperm from the testes. When the sperm mature, they are released into a tube called the vas deferens. The sperm travel up the vas deferens, where they mix with semen released by glands lining the vas deferens. They then travel through another tube called the urethra, which runs through the penis.
ACTIVITY (open a new Google document and title it 'Reproductive Health')
By now, you might know something of what to expect as you start experiencing the changes to your body and emotions caused by the onset of puberty.
Boys and girls discover this information through a variety of sources: parents or other significant adults in their lives, older siblings, teachers, peers or the media.
Use the Changes during puberty link as another source of information.
1. What advice would you give a friend struggling with the physical changes of adolescence? Provide at least four strategies to help your friend cope
WORK SHEET
By now, you might know something of what to expect as you start experiencing the changes to your body and emotions caused by the onset of puberty.
Boys and girls discover this information through a variety of sources: parents or other significant adults in their lives, older siblings, teachers, peers or the media.
Use the Changes during puberty link as another source of information.
1. What advice would you give a friend struggling with the physical changes of adolescence? Provide at least four strategies to help your friend cope
WORK SHEET