Period of development:

Period of development:

1. Spermatogenesis: 64 days

2. No.of primary oocyte
A. Before birth:- 7 millions
B. After birth:- 7 lakh to 2 million
C. At puberty:- 40,000 to 4 lakh
D. Ovulated:- less than 500

3. Meiotic division
A. M-1: just BEFORE OVULATION by LH
B. M-2: just before fertilization

4. Ovulation: 14 days prior menstruation

5. Fertilization: 48-72 hrs of ovulation

6. Morula (16 cell stage): 3-4th day

7. Implantation: 5-6th day

8. USG:-
A. Gestational ring: 5th WK of LMP
B. Gestational sac: 6th WK of LMP
C. Heart activity: 7th WK of LMP
(Reduce 1 WK in each, in case transvaginal usg is performed)

9. Life span of ovum: 1 day

10. Life span of sperm: 2-3 days

11. Somite: 3rd WK

12. Intra embryonic coelom: 4th WK

13. Brain, Kidney: 5th WK

14. Liver: 5th-10th WK

15. Adrenal: 6th WK

16. Primary ossification in clavicle: 6th WK (in other bones- 8th WK)

17. Physiological hernia appears at 6th WK, reduced at 10 th wk

18. Mammary gland: 7 th WK

19. Genitalia differentiation: 12th WK

20. Liver erythropoieisis: 8-12 wks

21. Urine formation: 9-12 wks

22. Quickening: 20th WK

23. Eye movt: 14th WK

24. Respiration: 26th WK

25. Splenic hemopoeisis: 26-28 wks

26. Pupillary reflex: 30 wks