The given figure illustrates montly changes in the human ovary during the reproduction cycle.

Which of the following statements most accurately describes each structure?

Options

A. Before puberty, the oocyte (A) does not start the process of meiosis.
B. The hormone produced by by structure (B) causes thinning of the uterine cervical mucus to allow passage of sperms.
C. During ovulation, structure (C) stays at the interphase between meiosis I and meiosis II.
D. The hormone produced by structure (D) stimulates the pituitary gland to secrete luteinising hormone.

Answer

B

Explanation

At birth, ovaries contain some 2 million follicles each with an ovum that has begun meiosis but is arrested in prophase of the first meiotic division. At this stage , the ova are called primary oocyte (labelled A). Primary oocyte completes first meiotic division to produce secondary oocyte (labelled C) Which gets arrested in the metaphase of meiosis II. The Graffian follicle (labelled B) secretes estrogen which causes thinning of cervicl mucus to allow easy passage of sperms through the cervix. Progesterone is secreted by corpus luteum (labelled D). It stimulates further development of uterine epithelium and mammary glands. It is also required for maintenance of pregnancy.