AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization Joining of sperm & egg ...

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AP Biology 2005-2006 Fertilization

Transcript of AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization Joining of sperm & egg ...

Page 1: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Fertilization

Page 2: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Fertilization Joining of sperm & egg

sperm head enters egg

Page 3: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Cleavage Repeated mitotic divisions of zygote

1st step to becoming multicellular unequal divisions establishes body plan

different cells receive different portions of egg cytoplasm & therefore different regulatory signals

Page 4: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Cleavage zygote morula blastula

establishes future development

Page 5: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

OrganogenesisUmbilical blood vessels

Chorion

Amnion

Yolksac

AllantoisFetal blood vessels

Maternal blood vessels

Bird embryo

Mammalian embryo

Placenta

Page 6: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Placenta Materials exchange across membranes

Page 7: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Human fetal development

7 weeks4 weeks

Page 8: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Sex determination

XY

XX

TestesY

Sperm Zygote

Zygote

Ovum

Sperm

Ovum

X

X

X

Indifferentgonads

SRY

No SRYOvaries

(Follicles do notdevelop until

third trimester)

Seminiferoustubules

Develop inearly

embryo

Leydig cells

Page 9: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Human fetal development10 weeks

Page 10: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Human fetal development

12 weeks 20 weeks

Page 11: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Human fetal development The fetus just spends much of the 2nd & 3rd

trimesters just growing …and doing various flip-turns & kicks inside amniotic fluid

Week 20

Page 12: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Human fetal development24 weeks (6 months; 2nd trimester)

fetus is covered with fine, downy hair called lanugo. Its skin is protected by a waxy material called vernix

Page 13: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Human fetal development30 weeks (7.5 months)

umbilical cord

Page 14: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Getting crowded in there!!32 weeks (8 months)

The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming

Page 15: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Birth

Hormone induction

positive feedback

Page 16: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

Intestine

Placenta

Umbilicalcord

Wall ofuterus

VaginaCervix

Birth (after 36 weeks)

Bladder

Page 17: AP Biology 2005-2006 Fertilization. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg.

AP Biology 2005-2006

The end of the journey!