Human Embryology: Pre-embryonic period to Neonates

Basics of Human Embryology

In this lecture we will discuss about the basics of human embryology.  before e start students should aware with few terminology.

• Pre-embryonic period – from fertilization to 2nd week.
• Embryo: From 2nd to 8th week the developing human is called embryo.
• Fetus: From 9th week onwards till birth the developing human is referred to as Fetus.
• Conceptus: Conceptus refers to fetus/embryo along with all the extraembryonic membranes ( product of conception).
• Zygote: Zygote is a fertilized ovum with diploid number of chromosomes.
• Neonate:  After 4 weeks of birth, the developing human is called neonate and the period called neonatal period.
• Perinatal Period: 2 week before and 2 week after birth the period is called perinatal period.
• Infant: During the first year of life, the developing human is called infant and the period is called as infancy.
• Childhood: About 15 months to 12-13 years age known as Childhood
• Puberty: In girls it occurs between 12-15 years and in boys it occurs between 13-16 years.
• Adolescence: This period extends from the first appearance of sign of maturity to the attainment of complete physical, mental, sexual and emotional maturity. females :10-18 years ; Males: 15-20 years.