6.1.2 Female Sexual Development

In females, the hormones responsible for sexual development and maintenance of reproductive functions are:

• Oestrogen (estrogen)
• Follicle stimulating hormone (FSH)
• Luteinizing hormone (LH)
• Progesterone

I) Estrogen

What it is: Estrogen is produced by the developing follicle in the ovaries under the influence of FSH.

Function:

- Estrogen is responsible for the development of female reproductive organs, such as the uterus, fallopian tubes, and secondary sexual characteristics during puberty.

Simple explanation: Estrogen is the main female sex hormone. It makes girls develop into women. It causes breast development, widening of hips, and growth of body hair.

II) Follicle Stimulating Hormone (FSH)

What it is: FSH (produced by anterior pituitary gland) is essential for the development of ovarian follicles.

Function:

• One of these follicles undergoes oogenesis and produces ovum or egg (female gamete).
• It also stimulates the estrogen production and prepares the body for ovulation.

Simple explanation: FSH helps the ovaries develop follicles and produce eggs. It also stimulates estrogen production.

III) Luteinizing Hormone (LH)

What it is: High concentration of estrogen inhibits the FSH secretion. This condition leads to the production of LH from anterior pituitary gland.

Function:

• LH causes the rupturing of matured follicle in which a developing ovum is present which ultimately released in the oviduct.
• This rupturing of matured follicle and the release of developing ovum is called ovulation.
• After ovulation, the LH transforms the ruptured follicle into a yellow-colored glandular mass, the corpus luteum to produce progesterone.

Simple explanation: LH causes ovulation (release of egg from the ovary). After ovulation, LH turns the ruptured follicle into the corpus luteum, which produces progesterone.

IV) Progesterone

What it is: Progesterone is produced by corpus luteum in the ovary.

Function:

• It plays an important role in preparing the body for pregnancy by thickening the uterine lining, which is essential for embryo implantation.
• High concentration of progesterone also inhibits the release of FSH.

Simple explanation: Progesterone prepares the uterus for pregnancy. It thickens the uterine lining so that a fertilized egg can implant.

Summary Table of Hormones in Sexual Development

For Your Information

FSH and LH are collectively called gonadotropins. Anterior lobe of pituitary gland releases FSH and LH under the stimulation of gonadotropin releasing hormone (GnRH) from hypothalamus.

Intermediate Level

Sexual development is controlled by hormones:

Males:

Females:

Key points:

• Testosterone and FSH are necessary for normal spermatogenesis.
• FSH and LH are collectively called gonadotropins.
• GnRH from hypothalamus stimulates FSH and LH release.
• Estrogen inhibits FSH secretion.
• LH causes ovulation.
• Progesterone prepares the uterus for pregnancy.

Important Points

• - Unlike other organ systems, the reproductive system is unique because it becomes functional at a certain age after birth, called puberty.
• - Sexual development that leads to puberty in both males and females is controlled by hormones.
• - The hormones are chemical messengers that are produced and released by endocrine glands in blood.
• - The hormones interact with their target cells due to the presence of specific receptors on the target cells.
• - In males, the hormones responsible for sexual development and maintenance of reproductive functions are testosterone and follicle stimulating hormone (FSH).
• - Testosterone is mainly produced by the specific cells of testes under the influence of pituitary gland hormone.
• - Testosterone is very important for the development of male reproductive organs during puberty.
• - It controls maturation of sperm and the maintenance of the male reproductive system.
• - It stimulates the development of spermatocytes into spermatids and eventually into mature sperm.
• - Testosterone also promotes the development of secondary sexual characteristics, such as the growth of facial hair, deepening of the voice, and increased muscle mass.
• - Follicle stimulating hormone (FSH) is produced by the anterior pituitary gland.
• - It stimulates these cells to support the development of sperm cells and regulate the early stages of spermatogenesis.
• - Both testosterone and FSH are necessary for normal spermatogenesis, but they act at different points in the process.
• - Testosterone promotes the final maturation of sperm and maintenance of the reproductive environment, while FSH initiates and regulates the early stages of sperm production.
• - In females, the hormones responsible for sexual development and maintenance of reproductive functions are oestrogen, follicle stimulating hormone (FSH), luteinizing hormone (LH), and progesterone.
• - Estrogen is produced by the developing follicle in the ovaries under the influence of FSH.
• - Estrogen is responsible for the development of female reproductive organs, such as the uterus, fallopian tubes, and secondary sexual characteristics during puberty.
• - FSH (produced by anterior pituitary gland) is essential for the development of ovarian follicles.
• - One of these follicles undergoes oogenesis and produces ovum or egg (female gamete).
• - It also stimulates the estrogen production and prepares the body for ovulation.
• - High concentration of estrogen inhibits the FSH secretion.
• - This condition leads to the production of LH from anterior pituitary gland.
• - LH causes the rupturing of matured follicle in which a developing ovum is present which ultimately released in the oviduct.
• - This rupturing of matured follicle and the release of developing ovum is called ovulation.
• - After ovulation, the LH transforms the ruptured follicle into a yellow-colored glandular mass, the corpus luteum to produce progesterone.
• - Progesterone is produced by corpus luteum in the ovary.
• - It plays an important role in preparing the body for pregnancy by thickening the uterine lining, which is essential for embryo implantation.
• - High concentration of progesterone also inhibits the release of FSH.
• - FSH and LH are collectively called gonadotropins.
• - Anterior lobe of pituitary gland releases FSH and LH under the stimulation of gonadotropin releasing hormone (GnRH) from hypothalamus.

Remember

• - Puberty = reproductive system becomes functional
• - Hormones = chemical messengers
• - Male hormones = testosterone and FSH
• - Testosterone = male reproductive organs, sperm maturation, secondary sexual characteristics
• - FSH = early stages of spermatogenesis
• - Female hormones = estrogen, FSH, LH, progesterone
• - Estrogen = female reproductive organs, secondary sexual characteristics
• - FSH = follicle development, oogenesis, estrogen production
• - LH = ovulation, corpus luteum formation, progesterone production
• - Progesterone = prepares body for pregnancy
• - FSH and LH = gonadotropins
• - GnRH = stimulates FSH and LH release

Common Mistakes

• 1. Confusing testosterone and estrogen.
• - Testosterone = male sex hormone.
• - Estrogen = female sex hormone.
• 2. Mixing up FSH and LH.
• - FSH = follicle development, spermatogenesis.
• - LH = ovulation, testosterone production.
• 3. Forgetting the role of progesterone.
• - Progesterone prepares the uterus for pregnancy.
• 4. Thinking only one hormone controls sexual development.
• - Multiple hormones work together.
• 5. Believing FSH and LH are only in females.
• - FSH and LH are present in both males and females.
• 6. Confusing the sources of hormones.
• - Testosterone = testes.
• - Estrogen and progesterone = ovaries.
• - FSH and LH = anterior pituitary.
• 7. Thinking puberty is controlled by a single hormone.
• - Puberty is controlled by a complex interplay of hormones (GnRH, FSH, LH, testosterone, estrogen, progesterone).

Quick Revision

60-Second Revision

• Puberty = reproductive system becomes functional
• Hormones = chemical messengers
• Male hormones = testosterone and FSH
• Testosterone = male reproductive organs, sperm maturation, secondary sexual characteristics
• FSH = early stages of spermatogenesis
• Female hormones = estrogen, FSH, LH, progesterone
• Estrogen = female reproductive organs, secondary sexual characteristics
• FSH = follicle development, oogenesis, estrogen production
• LH = ovulation, corpus luteum formation, progesterone production
• Progesterone = prepares body for pregnancy
• **FSH and LH** = gonadotropins
• GnRH = stimulates FSH and LH release
• Warning: Do not confuse testosterone (male) with estrogen (female). FSH and LH are present in both males and females.