CBSE Class 10 Science 2017 · Paper 531 · Question 21

Diagram: a front view of the human female reproductive system shows two ovaries, one on each side; an oviduct (fallopian tube) running from near each ovary to the upper part of the uterus; the uterus, a hollow pear-shaped organ in the middle; the cervix, the narrow neck of the uterus; and the vagina below it. The oviduct and the uterus are labelled (see the figure). Role of the placenta: the placenta is a special disc-like tissue embedded in the uterine wall. It has villi on the embryo’s side, surrounded by blood spaces on the mother’s side, which give a large surface area for glucose and oxygen to pass from the mother’s blood to the embryo. The embryo thus gets its nutrition from the mother’s blood through the placenta. Removal of wastes: the waste substances generated by the developing embryo are removed by transferring them into the mother’s blood through the placenta.