• In the life span development the shortest is the period of the newborn or infancy
• This period, which begins at conception and ends at birth, is approximately 270 to 280 days in length or nine calendar months.
• How life begins? o New life begins with the union of male sex cell and female sex cell. o These sex cells are developed in the reproductive organs, the gonads. o Male gonad is “testes” and female gonad is “ovaries” o Male sex cell is referred as “spermatozoon” and female sex cell is referred as “ovum”. o Male and female cells differ in two ways o Way 1: in terms of chromosomes
In mature ovum, there are 23 matched chromosomes (XX)
In mature spermatozoon, there will be 22 matched chromosomes (XX) and one unmatched chromosome (XY) o Way 2: in terms of preparatory stages
Male cells go through two preparatory stages – maturation and fertilization
Female cells go through three – maturation, ovulation and fertilization o Maturation
Maturation is the process of chromosome reduction through cell division: one chromosome from each pair goes to a subdivided cell, which in turn splits lengthwise and forms two new cells.
Maturation of cells does not occur until sex maturity has been attained. o Ovulation:
Ovulation is a preliminary stage of development limited to the female sex cells.
It is the process of escape of one mature ovum during the menstrual cycle. o Fertilization
Fertilization occurs at the time of conception.
It normally occurs while the ovum is in the Fallopian tube.
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Characteristics of Prenatal period:
• The specified characteristics have a long lasting effect on development during life span.
• Six important characteristics of prenatal period:
1. Heredity endowment (means donation) is fixed once and for all. Some changes will be there in physical and psychological traits, but in terms of quantitative not qualitative.
2.