Identify the human developmental stage shown below as well as the…

MCQ

Identify the human developmental stage shown below as well as the related right place ofits occurrence in a normal pregnant woman, and select the right option for the two, together.

A
Late morula $\to$ Middle part of Fallopian tube
B
Blastula $\to$ End part of Fallopian tube
✓
Blastocyst $\to$ Uterine wall
D
$8$-celled morula $\to$ Starting point of Fallopian tube

✓

Answer

Correct option: C.

Blastocyst $\to$ Uterine wall

c
(c) : After fertilization, zygote undergoes rapid mitotic divisions, called cleavage, which is characterized by absence of growth of daughter cells. This leads to the conversion of single celled zygote into a multicellular structure called blastocyst or blastula. Implantation or embedding of zygote into endometrium of uterus occurs in blastocyst stage. The various stages in the journey of a fertilized egg from fertilization in the Fallopian tube to the implantation site in the uterus is illustrated in the given figure.Blastocyst comes in contact with the endometrium inthe region of embryonal knob or embryonic disc. It adheres to the same. The surface cells of trophoblast secrete lytic enzymes which cause corrosion of endometrial lining. They also give rise to fingerlike outgrowths called chorionic villi. Chorionic villi and uterine tissue become interdigitated. Villi not only help in fixation but also absorption of nourishment.