HUMAN DEVELOPMENT

http://www.ich.ucl.ac.uk/ich/html/postcards/

http://www.lab.anhb.uwa.edu.au/mb140/CorePages/MaleRepro/malerepro.htm

www.DennisKunkel.

Human sperm have typical sperm structure. The human testis looks like the primate testis you looked at in lab.

The human ovary has the same structure as the cat ovary you have looked at in lab.

Fertilization and early cleavage.

The second cleavage in a human zygote.

Figure on P. 171 of your text.

Human cleavage

40-50 hr 60 hr

compaction

http://arbl.cvmbs.colostate.edu/hbooks/pathphys/reprod/fert/cleavage.html

http://www.alphascientists.com/embryology_images/index.html

Figure similar to that on P. 170 of your text.

“Hatching” from the zona pellucida.

Strypsin protease digests hole in zona pellucida

Human blastocyst - pre-implantation

Plasminogen activator will be secreted by the trophoblastic cells that form the

syncytiotrophoblast.

See figure of 6 day human blastocyst in lecture packet

See figure of implanting 6-7 day human blastocyst in lecture packet

Plasminogen activator will be secreted by the trophoblastic cells that form the

syncytiotrophoblast.

Heuser’s membrane is an ephemeral combination of extracellular matrix and hypoblast cells.

See figure of 8 day human embryo in lecture packet

See figure of end of second week human embryo in lecture packet

See beginning of 3rd week human embryo in lecture packet - primitive streak forming.

Figure illustrating spread of mesoderm between epiblast and hypoblast - like what happens in chicken embryos.

Movements in Gastrulation figure in lecture packet.

By the end of the 3rd week, chordin and noggin secreted by the chordamesoderm have blocked BMP-4. As a result,

neurulation occurs.

Human neurulation figure in lecture packet.

http://www.biology.iupui.edu/biocourses/n100/2k4ch39repronotes.html

Figure of human primitive streak and neurulatiopn at web link below

“Sequence of flexion in longitudinal section” figure in lecture packet.

Fourth week human embryo figure in lecture packet.

Eighth week human embryo figure in lecture packet.

Carnegie stages of human embryos

Carnegie stage 13 - human embryo

The Virtual Human Embryo Project

Carnegie stage 13 - human embryo

The Virtual Human Embryo Project

Carnegie stage 13 - human embryo

The Virtual Human Embryo Project

* Chorioallantoic placenta - chorion and allantois form placenta

*Hemochorial placenta - villi that are formed from the chorion are bathed in blood.

*Deciduous placenta - tears away from the uterine wall at birth causing hemorrhaging.

CLASSIFICATION OF THE HUMAN PLACENTA

Figure on page 290 of your text

Figure on page 284 of your text

Syncytiotrophoblast and Cytotrophoblast

Figure of 13th day blastocyst in lecture packet.

Development of the human placenta

Figure of placental development passed out in class

Figure of placental development passed out in class

Figure of placental development passed out in class

Figure of placental development passed out in class

Figure of placental development passed out in class

Figures on pages 284 and 290 of text.

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Turn on pic-in-pic

Conjoined twins

• May be caused by both genetic and environmental factors

• 1 in every 40,000 births, but often still born

• 1 in every 200,000 live births

• 75% are still born or die within 24 hr of birth

• More often female than male (3:1)