Reproduction in humans
Read the following passage carefully and answer the given questions.
The female reproductive system consists of a pair of ovaries, a pair of oviducts, a uterus, a vagina, external genitalia, and a pair of mammary glands. The ovaries produce the female gamete and some steroidal hormones. Ovarian follicles in different stages of development are embedded in the stroma. The oviducts, uterus and vagina are female accessory ducts. The uterus has three layers, namely perimetrium, myometrium and endometrium. The female external genitalia includes mons pubis, labia majora, labia minora, hymen and clitoris. The mammary glands are one of the female secondary sexual characteristics. Spermatogenesis results in the formation of sperm that is transported by the male sex accessory ducts. A normal human sperm is composed of a head, neck, a middle piece and tail. The process of formation of mature female gametes is called oogenesis. The reproductive cycle of female primates is called the menstrual cycle. The menstrual cycle starts only after attaining sexual maturation. During ovulation, only one ovum is released per menstrual cycle. The cyclical changes in the ovary and the uterus during the menstrual cycle are induced by changes in the levels of pituitary and ovarian hormones.
The tertiary follicle is characterised by:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Antrum
In oogenesis the follicle passes through stages: the primary follicle, the secondary follicle, the tertiary follicle and the Graafian follicle. The tertiary follicle is the stage in which a fluid-filled cavity appears inside the follicle.
(1) Antrum — Correct. This is the fluid-filled cavity. It is the feature by which the tertiary follicle is known.
(2) Polar body — Incorrect. The first polar body is a tiny cell that is cut off when the primary oocyte completes its first meiotic division. It is a product of the oocyte, and it is not the feature that marks the tertiary follicle.
(3) Zona pellucida — Incorrect. This membrane forms around the secondary oocyte at the stage when the tertiary follicle turns into the Graafian follicle. It does not define the tertiary follicle.
(4) Theca interna — Incorrect. This is the inner part of the theca layer. A new theca is already present in the secondary follicle, so it is not the feature that marks the tertiary follicle.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Gametogenesis – …
