From the eighth week till birth, the embryo is called _______.

Concept:

• Humans are sexually reproducing and viviparous.
• The reproductive events in humans include
  • formation of gametes (gametogenesis), i.e., sperms in males
    and ovum in females,
  • transfer of sperms into the female genital tract (insemination)
  • fusion of male and female gametes (fertilization)
  • formation of zygote
  • formation and development of blastocyst
  • its attachment to the uterine wall (implantation),
  • embryonic development (gestation)
  • delivery of the baby (parturition).

Explanation:

• After union with the sperm, the ovum enters the germinal period, a time of very rapid cell division, which lasts for about two weeks.
• This is followed by the embryonic period of about six weeks, during which structural development of the embryo takes place.
• The last stage of prenatal development is the fetal stage, which lasts from two months after conception until birth.
• From the beginning of the third month until birth, the
  time period is known as the foetal period.

Thus, from the eighth week till birth, the embryo is called a fetus.

Additional Information

Egg:

• An egg/ova cell is a female gamete.
• An egg is produced by the meiotic division of female reproductive cells/germinal cells.
• An ova is a single cell.

Zygote:

• Fertilization results in the formation of zygotes.
• The zygote divides repeatedly to give rise to a ball of cells.
• The cells then begin to form groups that develop into different tissues and organs of the body.

Embryo:

• The developing structure is termed an embryo.
• The embryo gets embedded in the wall of the uterus for further development.
• In this stage, all the major organs form, and the embryo becomes very fragile.