Copper T is used as an Intra Uterine Device (IUD) for contraception. Identify the correct statement for its mode of action.
(A) It is made up of ionized copper.
(B) It releases Cu ions that suppress sperm motility.
(C) It makes the uterus unsuitable for implantation.
(D) It decreases sperm phagocytosis within the uterus.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (B) and (C) only
A Copper T (CuT) is a copper releasing IUD: a small T-shaped device placed in the uterus through the vagina. The copper on it slowly releases copper ions inside the uterus.
(A) It is made up of ionized copper. — Correct as per NTA, though loosely worded. A Copper T is not made of ionized copper. It is a small device that carries copper, and this copper slowly releases Cu ions into the uterus. The statement uses “ionized copper” for these released ions, so it is taken as true.
(B) It releases Cu ions that suppress sperm motility. — Correct. This is the main action of a copper IUD. A sperm that cannot swim well cannot reach and fertilise the ovum.
(C) It makes the uterus unsuitable for implantation. — Correct as per NTA, though loosely worded. NCERT gives this action to the hormone releasing IUDs (Progestasert, LNG-20), as an addition to the effects all IUDs have; it does not name it for copper releasing IUDs such as the Copper T. The statement is still taken as true here: an embryo that cannot implant in the uterine wall cannot grow, so pregnancy does not start.
(D) It decreases sperm phagocytosis within the uterus. — Incorrect. The book says the reverse: IUDs increase phagocytosis of sperms. White blood cells in the uterus engulf and destroy more sperms. Option (2) is the only option that leaves (D) out.
NCERT Extract:
Population Stabilisation and Birth Control – “… Another effective and popular method is the use of Intra Uterine Devices (IUDs). These devices are inserted by doctors or expert nurses in the uterus through vagina. These Intra Uterine Devices are presently available as the non-medicated IUDs (e.g., Lippes loop), copper releasing IUDs (CuT, Cu7, Multiload 375) and the hormone releasing IUDs (Progestasert, LNG-20) (Figure 3.2). IUDs increase phagocytosis of sperms within the uterus and the Cu ions released suppress sperm motility and the fertilising capacity of sperms. The hormone releasing IUDs, in addition, make the uterus unsuitable for implantation and the cervix hostile to the sperms.”
Figure 3.2 Copper T (CuT)