Q.1. Explain the role of pituitary gonadotropins during the follicular and ovulatory phases of the menstrual cycle. Describe the shifts in steroidal secretions.
Answer- The menstrual flow is due to the breakdown of the lining of the uterine endometrium and blood vessels which forms the liquid discharged from the vagina. The menstrual cycle is controlled through the pituitary gland by the hypothalamus. Changes in the ovary and uterus during the menstrual cycle is due to the fluctuation in the levels of ovarian and pituitary hormones. Towards the end of the menstrual phase, the pituitary FSH eventually increases which causes the development of the follicles inside the ovaries. Both the FSH and LH attain a peak level during the mid of the cycle. This speedy secretion of LH leads to LH surge which induces rupture of the Graafian follicle and hence the ovulation. During the maturation of follicles, more of estrogen is secreted causing a surge in FSH and LH from the anterior pituitary. The LH surge causes ovulation. The LH also induces luteinisation. The LH hormone causes the conversion of the empty follicle into the corpus luteum. The Corpus luteum produces steroidal hormones – progesterone and estrogen. These hormones govern the growth and maintenance of the uterine endometrium for probable implantation.
Q.2. Explain in detail the difference between the meiotic division of oogenesis and spermatogenesis.
Answer- Spermatogenesis is the production process of sperm from the male germ cell whereas oogenesis is the production process of the eggs from the oogonia in females. Meiosis is different in spermatogenesis and oogenesis in the quantity of the end product. This unequal division is necessary to maintain the essential part of the cytoplasm. One minor part is detached as the polar body where a single daughter cell called the ovum is formed which is functional. But in spermatogenesis, four spermatids are produced which are functional and that later develops into spermatozoa.
| Oogenesis | Spermatogenesis |
| Production of eggs from oogonia | Production of sperm from spermatogonia |
| Takes place inside the ovary in females | Takes place inside the testes in males |
| All except the last phase takes place inside the ovary | All phases occur inside the testis |
| Early stages observed during the fetal period. Rest stages observed between puberty and menopause | A continuous process that is initiated from puberty and lasts until death |
| Matured from germinal epithelium overlying the ovary | Developed from the germinal epithelial lining of the seminiferous tubules |
| Sertoli cells not found in germinal cell epithelium | Sertoli cells found in germinal cell epithelium |
| Few oogonia divide to produce eggs, one at a time | Spermatogonia are divided by meiosis to produce sperms |
| Lengthy growth phase in oogonia | The growth phase of spermatogonia is short |
| Generates non-motile gametes | Produces motile gametes |
| Primary oocyte divides to form a secondary oocyte and polar body during meiosis-I | During meiosis-I, primary spermatocyte divides to form two secondary spermatocytes |
Q.3. What is Reproduction? Explain How do humans reproduce their young ones?
Answer- Reproduction is a biological process of producing young ones or offspring, which are identical to their parents. There are two different modes of reproduction and are classified mainly based on the involvement of the parents.
The two different modes of reproduction are:
Asexual Reproduction: This mode of reproduction involves only one parent and the new offspring produced is genetically similar to the parent.
Sexual Reproduction: This mode of reproduction involves the formation and transfer of gametes, followed by fertilization, the formation of the zygote, and embryogenesis. It is very complex.
Humans reproduce their young ones through the sexual mode of reproduction.
Q.4. How many eggs does a woman have?
Answer- As a fetus early in development, a female produces about 6 million to 7 million eggs.
At birth, there are approximately 1 million eggs. By the time of puberty, only about 300,000 remains. Out of these, only 200 to 300 will be ovulated during a woman’s reproductive lifetime. Fertility can drop as a woman ages due to decreasing number and quality of the remaining eggs.
Q.5. What is the female reproductive system?
Answer- The female reproductive system includes both the internal and external organs. These organs are mainly involved with the reproduction process.
- Internal Reproductive Organs
The internal reproductive organs of females include the vagina, uterus (womb), cervix, fallopian tubes and ovaries.
- External Reproductive Organs
The vulva consists of all of the external parts of females reproductive organs.
Q.6.What is Menopause?
Answer- Menopause is defined as the final stage or the end of a woman’s menstrual cycle, fertility and the different types of changes a woman experiences. This is a natural process in all females and happens in all elder women’s, between the age of 40s to 50s and may also vary. The main cause for the Menopause is the female sex hormone levels, which naturally reduces along with the age and eventually ovaries stop releasing the eggs. Therefore, women’s in this phase are no longer have periods or be able to get pregnant.
Q.7.What is the menstrual cycle? Name the Hormones, which controls the menstrual menstrual cycle.
Answer- The menstrual cycle is defined as the natural process, which occurs in all females after reaching the age of their puberty. During this period, an ovary releases a mature egg, the egg travels to the uterus, if the egg is not fertilized, the uterine lining is shed and a new cycle begins. Overall a menstrual cycle lasts for 28 days. This cycles may either last for 21 days or as long as 35 days in some individuals.
The entire process of the menstrual cycle is controlled by the endocrine system and the hormones involved are FSH, LH, estrogen, and progesterone. Both FSH and LH hormones are produced by the gen and progesterone hormones are produced by the ovaries.
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