question_answer

The graph given below is representing the reproductive cycle in females. Analyse the graph and answer the questions given below.

(i) Identify the hormones marked as 'X' and 'Y'.

(ii) Name the ovarian phases of menstrual cycle during the following periods

(a) 5th - 12th day of the cycle.

(b) 14th day of the cycle.

(c) 16th - 25th day of the cycle.

(iii) What influence do hormones 'X' and 'Y' have on different ovarian events stated in (ii) (a), (b) and (c)?

Or

Male and female gametes in human beings differ from each other in both structure and function. Enumerate some major differences between the two, alongwith their diagram.

Answer:

(i) Hormone 'X' is Luteinising Hormone (LH).
Hormone ?Y? is Follicle Stimulating Hormone (FSH).
(ii) The ovarian phases of menstrual cycle during the following periods are
(a) 5th - 12th day - Follicular phase (proliferative phase),
(b) 14th day of cycle-Ovulatory phase (release of ovum).
(c) 16th - 25th day -Luteal phase.
(iii) (a) FSH is secreted by the anterior pituitary, which stimulates the ovarian follicle to secrete oestrogen, which inturn stimulates the proliferation of the endometrium of the uterine wall.
(b) Both LH and FSH attain a peak level in the middle of the cycle (about 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle is called LH surge. It induces the rupture of Graafian follicle followed by the release of an ovum (ovulation).
(c) The remaining cells of ovarian follicles are further stimulated by the LH to develop corpus luteum which secretes large amount of progesterone, a hormone essential for the maintenance of endometrium.
Or
Differences between male gamete (sperm) and female gamete (ovum) of human beings are given below
Male gamete (Sperm)	Female gamete (Ovum)
Male gametes (sperms) are produced inside the testes.	Female gametes (ova) are produced inside the ovary.
The maturation of sperms requires approximately 64 days.	The maturation of ova requires several years.
Millions of sperms are produced per day.	Only one ovum is produced every 28 days.
Sperms are motile in nature.	Ovum is non-motile in nature.
Reserve food material is less.	Reserve food material is sufficient.
A sperm is differentiated into four parts, i.e. head, neck, middle piece and tail.	Ovum is not differentiated into different parts.