Question

About the Female Reproductive System and development. answer the following questions:

1. Briefly describe the development of an egg, oogenesis, in the female reproductive system including the various hormones involved in the process. This may take 5-6 sentences to properly cover the main parts.
2. What is the role of estrogen and progesterone in the development and ovulation of a secondary oocyte?
3. On average, a woman's cycle occurs every 28 days. Describe and differentiate what is happening during the proliferative phase and the secretory phase of the endometrium.
4. Describe the process of puberty in both males and females and how it prepares the body for reproduction.

Answer 1

Oogenesis is the process of formation of mature female gamete Or ova. Ogenesis starts at the embryonic stage , when a couple of millions gamete mother cell (oogonia) are formed in the ovaries of fetus. After birth no more oogonia are formed. These cell enter into meiosis and remain arrested in prophase I stage untill puberty is reached. This arrested cella are known as primary oocyte. Primary oocyte is surrounded by a layer of granulosa cell and is called primary follicle. These follicles degenrate itself from birth untill puberty such that, only 60,000-80000 of follicles are left in each ovary at puberty.The primary follicles get surrounded by more layers of granulosa cells and a new theca and are called secondary follicles.The secondary follicle soon transforms into a tertiary follicle which is characterised by a fluid filled cavity called antrum. it is at this stage that the primary
oocyte within the tertiary follicle grows in size and completes its first meiotic division due to release of anterior pituitary hormone. The first meiotic division is regulated by hormones such as follicle stimulating hormone (FSH), estrogen, luteinizing hormone (LH), and progesterone. It is an unequal division resulting in the formation of a large haploid secondary oocyte and a tiny first polar body. Tertiary follicle further changes into the mature follicle or Graafian follicle which ruptures to release the secondary oocyte
(ovum) from the ovary by the process called ovulation.

Role of estrogen and progesterone-

Progesterone is awall steroid hormone which prepare the endometrium for implantation to occur. It thickens the endometrium wall. If an fertiliser egg gets implanted, corpeus luteum secrets progesterone needed for maintaining.

Estrogen is responsible for the growth and regulation of the female reproductive system and secondary sexual characteristics. Estrogen is produced by the granulosa cells of the developing follicle and exerts negative feedback on LH production in the early part of the menstrual cycle. However, once estrogen levels reach a critical level as oocytes mature within the ovary in preparation for ovulation, estrogen begins to exert positive feedback on LH production, leading to the LH surge.

Proliferative phase and secretary phase

Proliferative phase also known as follicular phase is the first phase after your mensus stop. During this phase, ovary grow to become fully mature graffian follicles and simultaneously regenerates the lining of endometrium. The release of gonadotrophins (leutinizing hormone and follicle stimulating hormone) increases and stimulate the follicular development and secretion of estrogen by growing follicles. Both LH and FSH attain a peak levelovum in the middle of cycle (about 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle called LH surge induces rupture of Graafian follicle and thereby the release of ovum (ovulation). The marks the secretary (luteal ) phase during which the remaining parts of the Graafian follicle transform as the corpus luteum. The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium (thickens the endometrium) required for implantation followed by pregnancy. The combination of estrogen and progesterone suppresses GnRH, which prevents any more follicles from maturing.

once LH secretion falls below a certain level, the corpus luteum degenerates, levels of estrogen and progesterone fall, the uterine lining is shed, and the next cycle begins.

Puberty in males and females -

Puberty is when a child's body start physical changes to attain a sexual maturity.

First sign of puberty in girls follow -

• breast development
• tenderness of breast bud
• Growth of pubic hair

Later sign include-

• Continued growth of breast
• Curlier and thick public hair
• More sweat
• Begining of mensuration (menarch)
• Underarm hair growth
• Acne
• White vaginal discharge
• Fat deposition in thigh, upperarm upperback
• Fully developed genital
• Stop growing taller

First sign of puberty in boys -

• testicles get bigger and the scrot-um begins to thin and redden
• pubic hair also starts to appear at the base of the pen-is

Later sign of puberty in boys -

• the pen-is and testicles grow and the scro-tum gradually becomes darker
• Voice become deep and cracken
• More sweat
• Facial hair growth
• Genetial hair growth
• More muscular
• Acne
• Become more taller