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Hi everyone, 

    3  Major prenatal period

  • Germinal period
  • Embryonic period
  • Fetal period
  1. Germinal period: this is for 2 weeks,. Zygote forms after fertilization which after passing through fallopian tube, get implanted on uterus.
  2. Embryonic period- this is from 3 weeks to 8 weeks. Most major organs like heart, brain etc form in this stage. basic structure of eyes, ears, nose, mouth form in this stage.
  3. Fetal period- it is from 9 weeks till birth. it is final stage. In this, elaborate development of brain and nervous system occur, Sex organs of fetus also develop in this stage ( Lumen Learning, n.d.-b).

Extra embryonic membrane develop from: ectoderm forms inner layer of amnion, Mesoderm form chorion, outer membrane of amnion, umbilical cord (Saladin, K. S., 2020).

Endoderm form yolk sac and allantois.

Reference:

Lumen Learning. (n.d.-b). Prenatal development | Lifespan development. https://courses.lumenlearning.com/suny-lifespandevelopment2/chapter/prenatal-development/

Saladin, K. S., (2020). Anatomy & Physiology: The Unity of Form and Function. (9th

            Edition). McGraw-Hill Higher Education.