Test: Menstrual Cycle (NCERT) - NEET MCQ

In the luteal phase of the menstrual cycle, following ovulation, the corpus luteum forms and secretes progesterone. Progesterone causes the endometrium to become thick, glandular, and vascular, preparing it for potential implantation of a fertilized egg.

Line in NCERT: "The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium."

Lack of menstruation may be indicative of pregnancy. During pregnancy, the levels of estrogen and progesterone are high in the blood, which are required for the maintenance of uterus and thus, menstruation does not occur. On 14th day of the menstrual cycle, there is rapid increase in LH (called LH surge), that induces ovulation. The changes in the ovary and the uterus are induced by changes in the levels of ovarian hormones and pituitary hormones. In the absence of fertilisation, corpus luteum degnerates.This causes disintegration of the endometrium leading to menstruation, marking a new cycle

Line in NCERT: "During pregnancy all events of the menstrual cycle stop and there is no menstruation." "In the absence of fertilisation, the corpus luteum degenerates." "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)."

During the follicular phase, the secretion of FSH happens and this leads to the development of a mature follicle (Graafian follicle). This process of formation of a mature female gamete is called oogenesis. The FSH level increase causes the development of follicles and secretion of estrogen by the growing follicles. Rapid secretion of LH leads to the rupture of Graafian follicle and release of ovum called ovulation. This phase is followed by the remaining parts of Graafian follicle transform into the corpus luteum. 

So, the correct option is '(i) →→ (iii) →→ (v) →→ (iv) →→ (ii)'.

Line in NCERT: "gonadotropins (LH and FSH) increases gradually during the follicular phase, and stimulates follicular development as well as secretion of estrogens by the growing follicles. Both LH and FSH attain a peak level 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 ovulation (ovulatory phase) is followed by the luteal phase during which the remaining parts of the Graafian follicle transform as the corpus luteum."

Progesterone is required for the maintenance of the endometrial lining of the uterus. As soon as the production of progesterone is reduced due to reduction in the production of LH from anterior lobe of the pituitary, the endometrium of the uterus breaks down and menstruation begins.

Line in NCERT: "The menstrual flow results due to breakdown of endometrial lining of the uterus and its blood vessels which forms liquid that comes out through vagina."

 
If mammalian ovum fails to get fertilized the estrogen secretion does not decrease further while corpus luteum will disintegrate. Primary follicle starts developing and progesterone secretion rapidly declines.

Topic in NCERT: MENSTRUAL CYCLE

Line in NCERT: "In the absence of fertilisation, the corpus luteum degenerates."

The correct sequence of the various phases of a typical menstrual cycle is:

- Menstrual
- Follicular
- Ovulatory
- Secretory

Explanation:
- Menstrual phase: Shedding of the uterine lining
- Follicular phase: Maturation of follicles in the ovary
- Ovulatory phase: Release of an egg from the ovary
- Secretory phase: Preparation of the uterus for possible pregnancy by thickening the lining

Therefore, the correct sequence is Menstrual → Follicular → Ovulatory → Secretory, which corresponds to option B.

Line in NCERT: "The cycle starts with the menstrual phase, when menstrual flow occurs and it lasts for 3-5 days. The menstrual phase is followed by the follicular phase."

During pregnancy, high levels of progesterone inhibits FSH and LH secretion. In absence of these hormones, there is no chance of ovulation and thus no pregnancy.

During the follicular phase of the menstrual cycle, the following occurs:

The primary follicle grows and becomes a fully mature Graafian follicle.

The endometrium of the uterus regenerates through proliferation.

Follicle Development:

• The primary follicle grows in response to follicle-stimulating hormone (FSH).
• It develops into a secondary follicle and eventually becomes a mature Graafian follicle, ready for ovulation.

2. Endometrial Regeneration:

• The endometrium (uterine lining) regenerates and thickens through proliferation, preparing for possible implantation of a fertilized egg.

Correct Answer: C: I and II

Thus, both statements I and II are correct.

Line in NCERT: "The primary follicle grows and becomes a fully mature Graafian follicle." "The endometrium of the uterus regenerates through proliferation."

Menstruation occurs for 1−5 days and ovulation occurs on 14th day of a normal menstrual cycle.

Line in NCERT: "The menstrual flow results due to breakdown of endometrial lining of the uterus and its blood vessels which forms liquid that comes out through vagina."

The menstrual cycle is a series of cyclic physiological changes that take place in the female primates. It is regulated by the various hormones like FSH, LH, estrogen, progesterone. The follicle-stimulating hormone stimulates the development of follicles which secretes estrogen. The rise in the level of estrogen stimulates the thickening of the endometrium in the uterus. LH is secreted by the pituitary gland which causes ovulation. The rise in LH level is followed by the rise in the progesterone which is responsible for developing the follicles into corpus luteum. The corpus luteum secretes progesterone which is necessary for the maintenance of the uterus lining for implantation. The rise in progesterone and estrogen results in the decrease of FSH and LH. If there is no pregnancy, then the level of progesterone and estrogen decreases which results in the breaking of the endometrium i.e., menstrual flow. After the start of menstruation, the level of FSH and LH rises to start the new cycle.

Line in NCERT: "gonadotropins (LH and FSH) increases gradually during the follicular phase, and stimulates follicular development as well as secretion of estrogens by the growing follicles. Both LH and FSH attain a peak level 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)."