The document outlines the processes involved in human reproduction from oogenesis and spermatogenesis to fertilization and fetal development. It details the stages of gamete formation, the fertilization process leading to zygote formation, and the critical phases of embryonic development up to birth. Key points include the duration of spermatogenesis, stages of embryonic growth, and the overall gestational timeline.

1. FROM
CONCEPTION TO
CHILDBIRTH
UTSHA CHAKRABORTHY
EMBRYOLOGIST
FEMELIFE FERTILITY FOUNDATION
www.femelife.com
www.wikiHealthNews.com

2. PROCESSES INCLUDED IN CHILD
BIRTH
• OOGENESIS
• SPERMATOGENESIS
• FERTILIZATION
• CLEVAGE
• CELL DIVISION
• CELLULAR DIFFERENTIATION:
*GASTRULATION
*NEURULATION
*ORGANOGENESIS

3. EMBRYO :

4. FIRST STEP IS OOGENESIS
Process: Formation of ova from the
Primary oocyte is oogenesis.
*oocytogenesis is formation of primary
Oocyte, which is completed in 20
Weeks of foetal age.
*400,000 primary ova are present
At the time of birth, which
Remain dormant till ovulation.
*CELL DIVISION gives rise to
Secondary oocyte capable of
fertilization on maturation.

5. DETAILS OF OOGENESIS
• FEMALE GAMETOGENESIS:
• Development of female germ cells into a
new INDIVIDUAL.
• DIPLOID precursor cells undergo cell
division and differentiation to form
mature HAPLOID gamete.
• Female gametes are ova produced in
the ovaries.
• ONLY 1 diploid OVUM and 3 haploid
polar bodies are formed in this process(
which may degenerate later).

6. CHROMOSOMAL DIVISION
• OOGONIA:DIPLOID(2N) WITH 46
CHROMOSOMES
• PRIMARY OOCYTE:DIPLOID(2N)
WITH 46 CHROMOSOMES
COMPLETE FIRST MEIOTIC
DIVISION TO FORM
HAPLOID(N)SECONDARY
OOCYTE WITH 23
CHROMOSOMES
• HAPLOID(N) MATURE OVUM
WITH 23 CHROMOSOMES
FORMED AFTER SECOND
MEIOTIC DIVISION

7. CELL DIVISION • MITOSIS is equal division in which
daughter cells are genetically
identical to the parent cell.
• MEIOSIS is reduction division in
which daughter nuclei are
genetically non-identical to the
parent cell.
• MEIOSIS is the central feature of
gametogenesis
• Its responsible for genetic
diversity and repair of damage in
DNA TO BE PASSED to progeny.

8. SPERMATOGENESIS
• SPERMS OR SPERMATOZOA are the
male gametes which fertilize an
egg.
• SPERMATOGONIUM:DIPLOID(2N)/4
6 chromosomes*1
• PRIMARY
SPERMATOCYTE:DIPLOID(2N)/46
chromosomes*2
• SECONDARY
SPERMATOCYTE:HAPLOID(N)/23chr
omosomes*2
• SPERMATIDS:HAPLOID(N)/23chrom
osomes*4
• SPERMATOZOA:HAPLOID
(N)/23chromosomes*4
GENETICS RELATED TO SPERMATOGENESIS IN MAN

9. DETAILS OF SPERMATOGENESIS
*SPERMATOGENESIS is the process of
production of spermatozoa from
spermatogonial stem cells.
*SPERMATOGONIA yield PRIMARY
SPERMATOCYTES by mitotic division.
*EACH primary spermatocyte give rise to
2 SECONDARY SPERMATOCYTES BY
FIRST meiotic division.
*EACH secondary spermatocyte divides
into 2 SPERMATIDS BY MEIOSISǁ
*EACH spermatid differentiates into
SPERMATOZOA OR SPERMS.
*THE PROCESS TAKES 74 DAYS IN
HUMANS(minimum)
*TESTES produces 200-300million
sperms daily .

10. CHROMOSOMAL DISTRIBUTION
• C
• O
• M
• P
• A
• R
• I
• S
• I
• O
• N

11. FERTILIZATION IN HUMAN BEINGS
• FERTILIZATION is the process involving
FUSION of sperm nucleus with an egg to
form a DIPLOID cell, called ZYGOTE.
• SPERM binds through the CORONA
RADIATA.
• On encountering a SECONDARY OOCYTE,
the ACROSOME of the sperm bursts to
produce enzymes
which help it burrow through the ZONA
PELUCIDA.

12. POINTS ON FERTILIZATION
• THE SPERM PLASMA FUSES
WITH THE EGG PLASMA
MEMBRANE
• THE SPERM HEAD
DISCONNECTS WITH ITS
FLAGELLUM AND EGG
REACHES THE UTERUS DOWN
THE FALLOPIAN TUBE.
• THE GENETIC MATERIALOF
SPERM AND EGG COMBINES.

13. GROWTH AND IMPLANTATION
• THE DEVELOPMENT OF THE EARLY
EMBRYO UNTIL IMPLANTATION IS
COMPLETED IN THE UTERUS.
• CELL DIVISION AND CELLULAR
DIFFERENTIATION TAKES PLACE.
• EMBRYOGENESIS COVERS FIRST 8
WEEKS OF DEVELOPMENT.
• THE BLASTOCYST GETS IMPLANTED.
• THIS STUDY IS CALLED EMBRYOLOGY.

15. FOETAL DEVELOPMENT • THE GESTATION PERIOD IS 38 WEEKS
OR 9 MONTHS(mo)
• AT THE BEGINNING OF 9th WEEK ,THE
EMBRYO IS CALLED FOETUS.
• THE GERMINAL STSGE TAKES AROUD
10 DAYS DURING WHICH ZYGOTE
BEGINS TO DIVIDE BY CLEAVAGE.
• GASTRULATION DURING WHICH
3GERM LAYERS OF THEEMBRYO FORM
IN A PROCESS CALLED HISTOGENESIS.
• THEN COMES NEURULATION.
• THE PROCESS ENDS WITH
ORGANOGENESIS.
• HEART BEAT COMES AT AROUND
20WEEKS.