with polar body

http://www.drmalpani.com/embryos2.htm

Mature Sperm

http://www.ivf-infertility.com/infertility/investigations/

http://www.cours.fse.ulaval.ca/ten-20727/sitesdescours/000_3automne2000/

http://www.people.virginia.edu/~rjh9u/spermegg.html

At conception the haploid sperm (23 chromosomes) & haploid egg (23 chromosomes) combine to create a fertilized diploid cell with a full compliment of chromosomes (46)

http://www.people.virginia.edu/~rjh9u/twocell.html

http://www.people.virginia.edu/~rjh9u/4cell.html

36 hours after fertilization the zygote is no larger than the head of a pin. It is continuously dividing as it moves down the uterine tube.

http://www.hybridmedicalanimation.com/pages/

http://womenshealth.jhmi.edu/rei/conditions/art_

Fertilized zygote after 3 days (72 hours).

Rapid division has occurred and without growth. The zygote has note reached the uterus to implant.

http://www.people.virginia.edu/~rjh9u/blastcys.html

http://robby.nstemp.com/catalog.html

Zygote 4 days (96 hours) after fertilization.

The trophoblast cells that surround the blastocyst  develop into the placenta.

The large inner cell mass forms the embryo proper.

http://www.cdc.gov/ncbddd/folicacid/excite/Files

By day 22 the back portion is rolled in a tube the lower end becomes the spine and the upper end becomes the brain.

4 weeks

http://www.wprc.org/trimester1.phtml

4 weeks

The embryo is producing hormones that interrupt the mother’s menstrual cycle.

An amniotic sac and placenta have formed. Organs are beginning to differentiate and limb buds appear. Its heart begins beating between 4 and 5 weeks.

http://embryo.soad.umich.edu/carn

The heart is beating

http://embryo.soad.umich.edu/carnStages/

http://embryo.soad.umich.edu/carnStages/

44 days

Measure 13-17 mm in length

50 days

21-23 mm in length

Upper limbs slightly bent at the elbows, short stubby fingers, hands curving over the chest but still far apart from each

55-56 days

http://embryo.soad.umich.edu/carnStages/

7 & 8 weeks

http://www.alhuda.it/Islamscience/islam_scienze.asp?id=50

The limb buds and digits are forming. The retina forms. The fetus swims in the amniotic sac.

http://embryo.soad.umich.edu/carn

The heart, brain and vocal cords are complete.

The eyelids cover the eyes.

The fetus sometimes sucks its thumb.

http://pages.slic.com/rtlife/life.htm