Development YO!

By:

Lil’ Stevie & Kojack

1 day post-ovulation

• The fertilization process takes about 24 hours.

• A sperm can survive for up to 48 hours.

• Though 300 million sperm may enter the upper part of the vagina, only 1%, 3 million, enter the uterus.

4 days post - ovulation

• About four days after fertilization, the morula enters the uterine cavity.

• Cells flatten and compact on the inside of the cavity while the zona pellucida remains the same size

• The presence of the blastocyst indicates that two cell types are forming; the embryoblast, and the trophoblast.

13 days post-ovulation

• The yolk sac begins producing hematopoietic or non-nucleated blood cells.

13 days post-ovulation Continued

Chorionic villi "fingers" form in the "placenta" anchoring the embryo to the uterus. Blood vessels begin appearing first in the "placenta" surrounding the embryo. By the end of stage 6a, the embryo is attached to the developing placenta by a stalk later to become part of the umbilical cord

19 - 21 days post-ovulation

• Looking at the embryo from the top, the head end is wider than the tail end, with a slightly narrowed middle.

• Every ridge, bump and recess now indicates cellular differentiation.

• A head fold rises on either side of the primitive streak. The primitive streak now runs between one-fourth to one-third of the length of the embryo.

25- 27 days post-ovulation

• The embryo curves into a C shape. • The arches that form the face and neck are now

becoming evident under the enlarging forebrain. • A blood system continues to develop. • The beginning cells of the liver form before the

rest of the digestive system.

35 - 38 days post-ovulation

• As the brain has increased in size by one-third since the last stage, it is still larger than the trunk.

• Esophagus lengthens. Blood flow through the atrioventricular canal is divided into left and right streams, which continue through the outflow tract and aortic sac.

• The relative width of the trunk increases from the growth of the spinal ganglia, the muscular plate and the corresponding mesenchymal tissues.

44 - 48 days post-ovulation

• Nerve plexuses (network of intersecting nerves) begin to develop in the region of the scalp. Eyes are pigmented and eyelids begin to develop and may fold.

• Kidneys begin to produce urine for the first time.

44 - 48 days post-ovulation Continued

• The wrist is clearly visible and the hands already have ridges or notches indicating the future separation of the fingers and the thumbs.

• Ossification of the skeleton begins

53 - 54 days post-ovulation

Eyes are well-developed, but are still located on the side of the embryonic head.

Over the next few days, tongue development finishes.

Feet approach each other, but are still fan-shaped and the toe digits are still webbed.

61- 68 days post-ovulation

• Basic brain structure of the fetus is complete and now the brain mass rapidly increases.

• Sockets for all twenty teeth are formed in the gum lines. Face has human appearance - one example is the nasolacrimal grooveforming on the upper lip.

• Vocal cords form in larynx and fetus can make sounds.

• Fingernails begin to grow from nail beds.

61- 68 days post-ovulation Pic

Fingerprints and toe prints begin.

• About 2.8 ounces (80g). • Eyes are at final destination and face forward

rather than to the sides and reflexes, such as blinking, develop. Ears move to final position and stand out from head.

• Fingertips and toes develop the unique swirls and creases of fingerprints and toe prints.

• Blood circulation is completely functional.

Fingerprints and toe prints begin Pic

Inner ear bones harden, hearing possible

• Bones of the ear - hammer, anvil and stirrup - harden, making sound conduction possible.

• Bones, muscles and organs are growing steadily.

• Blood vessels, bones and organs are visible underneath a thin layer of wrinkled, translucent, pink skin.

Brain Surface Convolutions Begin

• Fetal brain's surface appears wrinkled.

• Rhythmic breathing and body temperature are now controlled by the brain.

• Production of red blood cells is entirely taken over by the bone marrow.

• Fetal body is two to three percent body fat.

Brain Surface Convolutions Begin Pic

Gastrointestinal system very immature.

• Gums now have ridges which may look like teeth. Head may now position (head-down) into pelvis getting ready for delivery.

• Gastrointestinal system is very immature and will not mature until three or fourth years after birth.

• Skin appears light pink because of blood vessels close to its surface.

Gastrointestinal system very immature Pic

Fetus now considered full term.

• Fifteen percent of body is fat, eighty percent of which is underneath the skin, the other twenty percent surrounds the organs.

• Fetal abdomen is large and round mainly due to the liver which is producing red blood cells.

• weight about 7.5 pounds (3.4kg)

Fetus now considered full term Pic

Resources

• http://www.visembryo.com/baby/index.html

• http://embryology.med.unsw.edu.au/wwwhuman/Stages/Stages.html