Human reproduction practice · Mixed difficulty

Option A (Zona pallucida) is correct because the zona pellucida is the primary glycoprotein layer surrounding the mammalian oocyte.

Option A (Prophase-I) is correct because primary oocytes are arrested in prophase I of meiosis at the time of birth.

Option D (Capacitation) is correct because capacitation refers to the physiological changes that sperm undergo in the female reproductive tract, enabling them to fertilize an egg.

Option D (All of the above) is correct because the LH surge causes the Graafian follicle to rupture, releasing the ovum, which is ovulation.

Option A (Labia Minora) is correct because the labia minora are external genitalia, while fimbriae, infundibulum, and isthmus are parts of the fallopian tube (internal genitalia).

Option D (Both (1) and (2)) is correct because during the menstrual phase, both progesterone and LH levels decrease significantly.

Option C (Lack of progesterone) is correct because progesterone maintains the endometrium, and its decline leads to the breakdown and shedding of the uterine lining during menstruation.

Option A (A-primary sex organs; B-secondary sex organs) is correct because primary sex organs produce gametes and secondary sex organs do not.

Option A (I and IV) is correct because testosterone influences male secondary sexual characteristics, and the placenta secretes estrogen.

Option B (Ovolysin) is correct because ovolysin (also known as hyaluronidase) is the enzyme present in the sperm acrosome that helps dissolve the egg membrane (zona pellucida).

Option B (Addition of one X chromosome) is correct because it represents a chromosomal abnormality (Klinefelter syndrome) that is not a typical characteristic of a normal human male.

Option A (Outer layer of trophoblast) is correct because chorionic villi are formed from the outer layer of the trophoblast, which interacts with the maternal blood supply.

Option C (If assertion is true but reason is false) is correct because while iodine deficiency can affect menstrual cycles, the reason provided (low estrogen and progesterone) is not the direct cause.

Option A (Endocrine gland) is correct because the placenta secretes hormones like hCG, hPL, estrogen, and progesterone, making it an endocrine gland.

Option D (5 & 5 respectively) is correct because each oocyte that completes meiosis produces one ootid and one second polar body. The woman had 3 live births and 2 still births, so 5 oocytes completed meiosis.

Option C (Primary follicle starts developing) is the correct answer because if fertilization fails, the corpus luteum degenerates, hormone levels decline, and a new cycle begins with the development of a primary follicle.

Option D (Both (a) and (b)) is correct because the first polar body is formed during oogenesis before birth, and the second polar body is formed after birth, during fertilization.

Option C (desidua capsularis) is correct because the decidua capsularis is the portion of the endometrium that encapsulates the embryo and is located between the embryo and the uterine cavity.

Option C (57.6 million) is correct because for normal fertility, 60% of sperms must have normal shape, size, and vigorous motility. With a sperm count of 80 million/mL in 3 mL, the total sperm count is 240 million. 60% of 240 million is 144 million. However, the question asks for the number of sperms with normal shape, size and vigorous motility per ejaculate of 3ml semen, and the correct calculation is 240 million * 0.6 = 144 million. The question states that 80 million sperms per ml is the count for normal fertility, and 60% of the total sperms must have normal shape, size and vigorous motility. Therefore, 80 million/ml * 3 ml = 240 million sperms. 60% of 240 million = 144 million * 0.4 = 57.6 million.

Option B (Testes of rabbit) is correct because Leydig cells, which produce testosterone, are found in the interstitial spaces of the testes in mammals, including rabbits.

Option C (Proliferative phase) is correct because the follicular phase of the menstrual cycle is characterized by the proliferation of the endometrium under the influence of estrogen produced by the developing follicle.

Option B (Obliteration of blastocoel) is correct because the blastocoel, the fluid-filled cavity within the blastula, is obliterated during gastrulation as the archenteron forms.

Option A (Hcg) is correct because hCG is a hormone produced by the placenta and excreted in the urine during pregnancy.

Option C (Oxytocin) is correct because oxytocin is secreted by the hypothalamus and released by the posterior pituitary gland, not the placenta.

Option B (Progesterone) is correct because progesterone levels peak during the luteal phase to prepare the uterus for implantation.

Option D (Syncytiotrophoblastic cells of the placenta) is correct because hCG is produced by the syncytiotrophoblast cells of the placenta shortly after implantation.

Option B (chorion, endometrium) is correct because the placenta is formed from the chorion of the embryo and the endometrium of the mother.

Option B (Secretion of oxytocin from maternal pituitary gland) is correct because the fetal ejection reflex triggers the release of oxytocin from the mother's pituitary gland, which then stimulates stronger uterine contractions.

Option D (Four) is correct because Seminal vesicles, Glans penis, Prostate gland, and Foreskin are parts of the male reproductive system.

Option A (Ectoderm) is correct because skin epidermis, tooth enamel, lens, cornea, brain, and spinal cord are derived from the ectoderm.