(a) What changes are seen in girls at the time of puberty?
(b) Name the organs that produce ova (or egg cells) in human females.
(c) Draw a labeled diagram of the human female reproductive system. With the help of this diagram, explain the working of the human reproductive system.
(d) Describe the process of fertilization in humans and the development of embryos briefly.

(a) In girls, the first sign of puberty is the development of breasts. Other characteristics observed in girls are growing hair in the pubic region and armpits, and initiation of the menstrual cycle.

(b) Ovaries are the organs that produce ova (or egg cells) in human females.

(c) The female reproductive system organs comprise the ovaries, fallopian tube (uterine tube), uterus, cervix, and vagina.         

The ovary produces one egg every month and is also responsible for the production of female hormones.

The fallopian tubes, also known as uterine tubes or oviducts, are the female structure that allows the transport of eggs from the ovary to the uterus. It is the structure where the fertilization of egg and sperm takes place.

The uterus prepares itself every month by thickening the endometrium lining of the uterus to receive a fertilized egg or a zygote. Ovulation is the process where an ovum is released from an ovary. In human females, the ovaries release an ovum (an egg cell) every 28 days after attaining the age of puberty. The embryo gets implanted in the soft lining of the uterus. The embryo implantation helps in the further development of the embryo and also to obtain nutrients and oxygen required for its development.

(d) Fertilization is the process where nuclei of a female gamete, an egg, and nuclei of a male gamete, sperm, unite together in the fallopian tube to form a single-celled diploid (2n) zygote. In human females, fertilization takes place in oviducts.

Fertilization is possible if mating takes place in between the menstrual cycle because, during the middle of the menstrual cycle, ovulation takes place. Thus, the ovum has been released from the ovary and remains in living condition for about 2 days. Thus, if mating takes place during this time, the sperms penetrate inside the female body and fuse with the released ovum so that fertilization can take place.


Zygote after undergoing repeated cell division forms an embryo that attaches itself to the uterine wall. Implantation or attachment of an embryo in the thick lining of the uterus (endometrium) is known as implantation. The embryo gets nourishment from the mother's blood through the placenta. The placenta possesses villi and blood vessels which help in the transfer of oxygen and glucose from the mother to the embryo.

[Extra information:
Puberty is the age at which the process of physical changes occurs where males and females attain sexual maturity and are capable of sexual reproduction.]


Simply Easy Learning

Updated on: 21-Mar-2023


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