Human Reproduction and Reproductive Health: Organs and Cycle

The correct answer is B, the ampulla of the fallopian tube. The ovum released at ovulation is picked up by the fimbriae of the infundibulum and meets the sperm in the ampulla, the wide middle part of the tube, where fusion takes place to form the zygote. A is wrong because the uterus is the site of implantation, not fertilisation; the blastocyst reaches it about a week later and attaches to the endometrium. C is wrong because the cervix is the narrow neck of the uterus through which the sperms pass on their way up; nothing fuses there. D is wrong because the ovary only releases the ovum; a fertilised egg in or near the ovary would be an abnormal ectopic pregnancy. This single distinction, fertilisation in the tube and implantation in the uterus, is the most repeated question from the chapter.

The correct answer is B, the Leydig or interstitial cells, which lie in the spaces between the seminiferous tubules of the testis and secrete androgens, chiefly testosterone, under the influence of luteinising hormone from the anterior pituitary. A is wrong because Sertoli cells lie inside the tubules and nourish the developing sperms, for which reason they are called nurse cells; this swap is the commonest error in the topic. C is wrong because the prostate is an accessory gland whose secretion forms part of the semen and does not make the hormone. D is wrong because the epididymis is a coiled duct where sperms are stored and mature; it secretes no sex hormone. Pair them once and for all: Sertoli nourishes, Leydig secretes. Testosterone is responsible for the secondary sexual characters of the male, such as the deepening of the voice and the growth of facial hair.

The correct answer is B, to nourish the developing sperms. Sertoli cells line the seminiferous tubules and provide nutrition and support to the germ cells as they divide and change into sperms, which is why they are called nurse cells; they are controlled mainly by follicle stimulating hormone. A is wrong because testosterone comes from the Leydig or interstitial cells outside the tubules. C is wrong because mature sperms are stored in the epididymis and the vas deferens, not within the Sertoli cells. D is wrong because the fluid part of semen is secreted by the accessory glands, namely the seminal vesicles, the prostate and the bulbourethral glands. Remember that the scrotum keeps the testis about two to two and a half degrees below body temperature, which this process needs.

The correct answer is B, enzymes that help it enter the ovum. The acrosome is a cap-like structure over the sperm nucleus filled with enzymes that digest the layers around the egg so that one sperm can fuse with it. A is wrong because the mitochondria are packed into the middle piece of the sperm and supply the energy for the lashing of the tail. C is wrong because the genetic material lies in the haploid nucleus of the head, below the acrosome, and the acrosome itself carries no chromosomes. D is wrong because the sperm draws its energy from the fluid around it and from its own mitochondria rather than from a glucose store in the head. The three parts of a sperm, head with acrosome, middle piece with mitochondria and tail for motion, are a standard diagram question.

The correct answer is C, human chorionic gonadotropin, usually written hCG. It is secreted by the trophoblast of the implanted blastocyst and then by the placenta, appears in the blood and urine within a few weeks of conception, and is unique to pregnancy, so test kits use antibodies against it. A is wrong because oestrogen is secreted through the cycle and in pregnancy as well, so it cannot confirm pregnancy. B is wrong for the same reason: progesterone rises in the luteal phase of every cycle even when there is no conception. D is wrong because prolactin from the anterior pituitary is the hormone of milk secretion and rises late in pregnancy and after birth. Note that the placenta also secretes human placental lactogen, oestrogen, progesterone and relaxin.

The correct answer is A, progesterone. After ovulation the ruptured Graafian follicle turns into the yellow body called the corpus luteum, which secretes large amounts of progesterone to thicken and maintain the endometrium for implantation. If fertilisation does not occur, the corpus luteum degenerates, progesterone falls and the endometrium is shed as the menstrual flow. B is wrong because oxytocin comes from the posterior pituitary and causes the uterine contractions of childbirth and the ejection of milk. C is wrong because follicle stimulating hormone is secreted by the anterior pituitary and acts on the ovary earlier in the cycle. D is wrong because thyroxine is the iodine containing hormone of the thyroid gland and has nothing to do with the ovarian cycle. In a pregnancy the corpus luteum is kept alive by hCG from the placenta for the first few months, which is why the periods stop.

The correct answer is B, day 14 and a surge of luteinising hormone. Rising oestrogen from the ripening follicle triggers a sharp rise in LH from the anterior pituitary in the middle of the cycle, and this surge bursts the mature Graafian follicle and releases the ovum. A is wrong because day 5 falls in the menstrual phase, when progesterone is low and the endometrium is being shed. C is wrong because day 21 lies in the luteal phase, when the corpus luteum is active, and oxytocin has no role in the ovarian cycle. D is wrong because day 28 is the end of the cycle, and prolactin is the hormone of milk secretion. Learn the four phases with their days: menstrual 1 to 5, follicular 6 to 13, ovulation about 14, luteal 15 to 28.

The correct answer is A, the Central Drug Research Institute, Lucknow. Saheli contains centchroman and is a non-steroidal pill taken once a week after an initial daily course, which makes it different from the combined hormonal pills that have to be taken daily and carry hormonal side effects. B is wrong because the All India Institute of Medical Sciences is a teaching hospital and research centre but is not credited with this drug. C is wrong because the Indian Institute of Science works mainly in the physical, engineering and basic biological sciences. D is wrong because the National Institute of Nutrition works on diet, nutrient requirements and food safety. The Central Drug Research Institute is a laboratory of the Council of Scientific and Industrial Research, which is why the question also appears in general science.

The correct answer is D, 2021. The amendment of 2021 kept termination up to twenty weeks on the opinion of one registered medical practitioner, allowed it between twenty and twenty-four weeks for certain categories of women such as survivors of rape or incest on the opinion of two practitioners, and removed the upper limit where a Medical Board diagnoses substantial foetal abnormality. A is wrong because 1994 is the year of the Pre-natal Diagnostic Techniques Act, which bans sex determination. B is wrong because 2003 is when the rules under that Act were tightened and it became the PCPNDT Act. C is wrong because no amendment of the MTP Act was made in 2017, although courts were deciding individual cases beyond twenty weeks around then. The original Act itself dates from 1971.

The correct answer is A. Colostrum is the thin yellowish milk secreted in the first days after delivery and is rich in antibodies, especially immunoglobulin A, which pass to the baby and protect it from infection at a stage when its own immune system is immature; this protection is called passive immunity. B is wrong because colostrum is not notable for iron, and infants draw mainly on the iron stored before birth. C is wrong because vitamin D is formed in the skin in sunlight and is often given as a supplement; it is not what makes colostrum valuable. D is wrong because colostrum is in fact low in fat and small in quantity, yet rich in protein and protective factors, which is why it should not be discarded as many traditions wrongly advise.

The correct answer is C, genital herpes. It is caused by a virus that stays latent in the nerve cells for life, so the attacks can be controlled with medicines but the infection cannot be completely cured; hepatitis B and HIV infection fall in the same group. A is wrong because gonorrhoea is a bacterial infection that can be cured with the right antibiotic if it is detected early. B is wrong because syphilis is also bacterial and curable, and untreated cases are dangerous only because the disease is left to advance. D is wrong because chlamydiasis, caused by a bacterium, is curable as well, like trichomoniasis. The lesson examiners want is that early detection matters, and that the viral infections among the sexually transmitted diseases are the ones that stay for life.