Question

Cleavage is repeated mitotic division which start in zygote at

• A. Fallopian tubes
• B. Infundibulum
• C. Isthmus of oviduct
• D. Uterus

Answer 1

The correct option is A Fallopian tubes

• Cleavage is the repeated mitotic division of zygote to form a solid ball of cells called morula which later changes into a hollow ball of cells called blastula.
• Cleavage of the human zygote occurs within the fallopian tube. It is holoblastic, i.e., it divides the zygote completely into daughter cells or blastomeres. The first cleavage takes place about 30 hours after fertilization.
• It divides zygote longitudinally into two blastomeres (one slightly larger than the other). The second cleavage occurs within forty hours after fertilization. It is at right angles to the plane of the first resulting in four blastomeres.
• The third cleavage takes place about 72 hours after fertilization. During these early cleavages, the young embryo moves slowly down the fallopian tube towards the uterus.

So, the correct answer is 'Fallopian tubes'.