DevelopmentRachel Miller

Gamete Formation

• Eggs develop in female’s ovaries- female is born germ cells in ovaries begin meiosis- division stops at prophase I- ovarian cells become primary oocytes- finish meiosis with fertilization by sperm

Gamete Formation

• Sperm develop in male testes- begins at puberty - spermatogenesis takes 64 days- several million sperm produced per day

Incorrect Gametogenesis can Cause:

- Down’s Syndrome- Klinefelter’s Syndrome- Edwards Syndrome- Spontaneous abortion

Embryonic Development

1) Fertilization2) Cleavage3) Morula4) Blastula5) Gastrula6) Extraembryonic Membrane Development

Fertilization1) Recognition

- sperm secretes protein

- binds with special receptor molecule on the zona pellucida- zona pellucida- glycoprotein membrane surrounding oocyte- insures fertilization between same species

Fertilization

2) Penetration- sperm and oocyte plasma membranes fuse

Fertilization

3) Fertilization membrane forms to block any more sperm

Fertilization

4) Oocyte undergoes meiosis II- produces an ovum and polar body- polar body released

Fertilization

5) Sperm and ovum nuclei fuse- zygote nucleus of 23 chromosomes

Cleavage

• Rapid cell divisions without cell growth• Microfilaments contract and pinch cell in two• Form smaller blastomeres

Cleavage

• Cytoplasmic Localization– Blastomeres receive different maternal messages– Inherit different proteins– Determines later cell lineages

Cleavage

Mammal Cleavage

• Embryos genome produces proteins for cleavage to occur

• Mammals take 12-24 hours for each cut• Mouse and goat- maternal to zygotic control

at two cell stage• Have rotational cleavage

Day 4: Morula

• Ball of 16- 32 cells

Blastula• Liquid fills morula and pushes cells out• Hollow, single layer of cells

Day 5: Blastocyst

1. Inner cell mass- few cells that will become actual embryo2. Zona pellucida 3. Trophoblast- develop into placenta4. Blastocoel- fluid filled cavity

Days 6-7: Blastula Hatches• Blastocyst adheres to uterine lining• Injected out of Zona Pellucida• Has now formed connections with mother’s

tissues

Ectopic Pregnancy

• Fertilized egg implants outside of uterus• Typically occurs in fallopian tubes• Fetus will burst organ

Days 10-14:

- Fluid filled amniotic cavity opens up- Amnion forms- will enclose embryo

- buoyant cradle and nourishment-Yolk sac starts to form- will make blood and germ cells- Embryo starts to form from embryonic disc - Chorion (placenta) starts to form

Days 10-141. Start of the embryonic disc2. Amniotic cavity- filled with fluid

-buoyant cradle and nourishment3. Yolk sac- gives rise to blood and germ cells4. Chorion (placenta) starts to form

4

Day 15: Gastrula

• Single layered blastula becomes double layered• Opening to outside

Day 15: Gastrula

• 3 Germ Layers for tissue to develop from- Ectoderm, Mesoderm, Endoderm

• Archenteron- center cavity• Blastopore- opening

Days 18-23: Morphogenesis

• Organs begin to form • Tissues fold• Neural folds merge to

make start of spinal cord and brain

• Somites- will become bones and dermis

Day 24-25

Pharyngeal arches will become:- face- neck- mouth- nasal cavities- larynx- pharynx

Differentiation

• All cells started out with same genes (from one fertilized egg)

• All transcribe many of same genes• Most have special functions

- Ex. red blood cells transcribe genes for hemoglobin

• Over time specific subsets of genes have been turned on

Inductive Cell from One Group Influences Development of Another

Pattern Formation

• Sculpting of specialized tissues and organs from clumps of cells in proper places in embryo in proper order

• Embryonic cell reads it genes• Makes and secretes molecules to neighbors• These signals induce changes

Cadherin and Integrin Signals

• Proteins that affect how cells link up in gastrula- will affect how organs form

• Signals activate/ inhibit adhesion proteins

HOX Genes

• Class of master genes that contain information about mapping out of body plan

HOX Genes

• All body appendages start out as tissue buds• Bud forms where Dll gene is expressed

- turned on- arm/leg forms- turned off- nothing

• Hox genes suppress DII when needed• DII expressed similarly across phyla

Fate Mapping• shows how a cell or tissue moves and what it

develops into

Polymelia

• Results in extra limb(s)- usually shrunken/deformed

Conjoined Twins

• normal identical twins- the egg splits at four to eight days after fertilization

• conjoined twins- the split occurs sometime after day 13

• Embryos do not fully separate

Rare Types

• Dicephalus: Twins that share one body, but have two separate heads and necks.

• Parasitic twins: This occurs when one smaller, malformed twin is dependent on the larger, stronger twin for survival.

• Fetus in fetu: In this unusual case, one fetus grows inside the body of the other twin

"Conjoined Twins Information on Healthline." Medical Information for Healthy Living | Healthline. Web. 14 Apr. 2011. <http://www.healthline.com/galecontent/conjoined-twins/2>.

http://www.metacafe.com/watch/122740/baby_born_with_2_heads/

Frank Lentini

Lakshmi Tatma

http://channel.nationalgeographic.com/episode/the-girl-with-eight-limbs-3966/02#tab-Videos/05349_00

A team of more than 30 surgeons worked in shifts. The surgery lasted for 27 hours. The doctors gave Lakshmi a 75-80% chance of survival during the surgery.

The steps of the operation were:

1.(8 hours): Abdominal operation: remove the parasite's abdominal organs.2.Remove the autosite's necrotic kidney and replace it with the parasite's kidney. Tie off the blood vessels that supplied the parasite.3.Move the reproductive system and the urinary bladder into the autosite.4.(6 to 8 hours) Amputate the parasite's legs at the hip joints: this caused heavy bleeding. Cut the joined backbone: the nervous system around the join was found to be extremely chaotic, and care had to be taken to avoid causing paralysis.5.Separation, at 12.30 am on 7 November 2007. The combined pelvic ring was divided through or near the parasite's hip joints and not at the pubic symphyses. The remaining incomplete pelvic ring was cut and bent to make the ends meet, and not left as an open part-circle.[4]6.External fixation to hold the parts of the pelvis in place. This caused the pelvis to close in 3 weeks to the normal position.7.(4 hours): Suturing. Operation completed at 10 am on 7 November 2007.

Works Cited"Biological Diversity 9." Estrella Mountain Community College. Web. 14 Apr. 2011. <http://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookDiversity_9.html>. "The Carnegie Stages." Accueil/Home. Web. 14 Apr. 2011. <http://www.embryology.ch/anglais/iperiodembry/carnegie02.html>. "Conjoined Twins Information on Healthline." Medical Information for Healthy Living | Healthline. Web. 14 Apr. 2011. <http://www.healthline.com/galecontent/conjoined-twins/2>. "Dynamic Development at a Glance." University of Calgary Webdisk Server. Web. 14 Apr. 2011. <http://people.ucalgary.ca/~browder/virtualembryo/dydev_at_glance.html>. "Ectopic Pregnancy." KidsHealth - the Web's Most Visited Site about Children's Health. Web. 14 Apr. 2011. <http://kidshealth.org/parent/pregnancy_center/your_pregnancy/ectopic.html>. "Evolution 101: Understanding Complexity." Understanding Evolution. Web. 14 Apr. 2011. <http://evolution.berkeley.edu/evosite/evo101/IIIC6cComplexity2.shtml>. "Frank Lentini - The Human Tripod." P H R E E Q U E S H O W. Web. 14 Apr. 2011. <http://www.phreeque.com/frank_lentini.html>. Heyer, Bruce. "Animal Tissues & Development." Web. 14 Apr. 2011. <http://facultyfiles.deanza.edu/gems/heyerbruce/F.Tissues.pdf>. "Human Reproduction." Department of Biology. Web. 14 Apr. 2011. <http://www.biology.iupui.edu/biocourses/N100/2k4ch39repronotes.html>. "La Pénétration Du Spermatozoïde Dans L'ovocyte." Accueil/Home. Web. 14 Apr. 2011. <http://www.embryology.ch/francais/dbefruchtung/eindring03.html>. "Morphogenetic Movements." Home. Web. 14 Apr. 2011. <http://worms.zoology.wisc.edu/dd2/echino/gast/morph/morph.html>. Pack, Phillip E. CliffsAP Biology. Hoboken, NJ: Wiley Pub., 2007. Print. "Rediscovering Biology - Unit 7 Genetics of Development: Animations and Images." Learner.org. Web. 14 Apr. 2011. <http://www.learner.org/courses/biology/units/gendev/images.html>. "Rediscovering Biology - Unit 7 Genetics of Development: Animations and Images." Learner.org. Web. 14 Apr. 2011. <http://www.learner.org/courses/biology/units/gendev/images.html>. "Sexual Reproduction: Involves the Joining of Sperm and Egg Cells." Web. 14 Apr. 2011. <http://infohost.nmt.edu/~klathrop/SexualReproduction.htm>. "Water Quality Testing: Sea Urchin Fertilization Test." SMCCD.NET Redirection Page. Web. 14 Apr. 2011. <http://www.smccd.net/accounts/snitovsky/watertest.htm>.