Welcome to The Visible Embryo

Home- - -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- News Alerts -Contact

Welcome to The Visible Embryo, a comprehensive educational resource on human development from conception to birth.

The Visible Embryo provides visual references for changes in fetal development throughout pregnancy and can be navigated via fetal development or maternal changes.

The National Institutes of Child Health and Human Development awarded Phase I and Phase II Small Business Innovative Research Grants to develop The Visible Embryo. Initally designed to evaluate the internet as a teaching tool for first year medical students, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than ' million visitors each month.


WHO International Clinical Trials Registry Platform
The World Health Organization (WHO) has created a new Web site to help researchers, doctors and patients obtain reliable information on high-quality clinical trials. Now you can go to one website and search all registers to identify clinical trial research underway around the world!



Home

History

Bibliography

Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System

Contact The Visible Embryo

News Alerts Archive

Disclaimer: The Visible Embryo web site is provided for your general information only. The information contained on this site should not be treated as a substitute for medical, legal or other professional advice. Neither is The Visible Embryo responsible or liable for the contents of any websites of third parties which are listed on this site.
Content protected under a Creative Commons License.

No dirivative works may be made or used for commercial purposes.

Return To Top Of Page
Pregnancy Timeline by SemestersFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
Click weeks 0 - 40 and follow fetal growth
Google Search artcles published since 2007
 
April 29, 2011--------News Archive

Catching Autism At The 1-year Well-Baby Check-Up
A novel strategy developed by autism researchers at the University of California, San Diego, shows promise as a simple way to detect cases of Autism Syndrome.

A New Wrinkle In The Genetic Code
Long ago a mouse was created that is just now teaching us that mutations in the proteins produced from ribosomes can lead to unexpected birth defects.


April 28, 2011--------News Archive

Tired Neurons Nod Off in Sleep-Deprived Rats
The more rats are sleep-deprived, the more neurons take catnaps. Though the animals are awake and active, neurons in the cortex, are briefly falling asleep.

Obese Adolescents Lacking Vitamin D
Vitamin D status is significantly associated with muscle power/force; a deficiency may interfere with the obese adolescent's ability to increase physical activity.


April 27, 2011--------News Archive

Men and Women Respond Differently to PTSD
Men and women had starkly different immune system responses to chronic post-traumatic stress disorder. Men show no response, women show a strong one.

Motor Protein May Offer Promise In Ovarian Cancer
A regulatory motor protein can block ovarian tumor growth, leading to cancer cell death and new therapies to treat the disease.


April 26, 2011--------News Archive

Protein Levels Could Signal Childhood Diabetes
Decreasing blood levels of a protein that helps control inflammation may be a red flag that could help children avoid type 1 diabetes.

Best Treatment For Gestational Tumors
A clinical trial has sifted out the most effective chemotherapy regimen for quick-growing but highly curable cancers arising from the placentas of pregnant women.


April 25, 2011--------News Archive

Frog Embryos Teach Us About Heart Development
Thanks to new research at the University of Pennsylvania, there is new insight into the processes that regulate the formation of the heart.

Brain Cells Offer Insight on How Cancer Spreads
The mechanism regulating embryonic development in plants displays similarities to a signalling pathway in embryonic stem cells in mammals.

WHO Child Growth Charts

Researchers at Fred Hutchinson Cancer Research Center may have found a new mechanism by which other types of cells, including cancer cells, travel within the body.

The findings by Jonathan Cooper, Ph.D., member and director of the Hutchinson Center’s Basic Science Division and Yves Jossin, Ph.D., member and director of the Hutchinson Center’s Basic Sciences Division, and Yves Jossin, Ph.D., a research fellow in Cooper’s laboratory, published online April 24 in Nature Neuroscience, could lead to a better understanding of neurological development and, possibly, cancer metastasis.

During normal development cells divide, arrange themselves in appropriate patterns, and specialize to form discrete tissues and organs. For the body to

Neuron Migration
Some normal neuron nuclei are tracked in green (appearing cyan in the image as they are labeled both blue and green). Many neurons have reached the top of the cortex.
Some
abnormal neuron nuclei are tracked in red (appearing yellow where they are superimposed on green, normal neurons).
Abnormal neurons are blocked in the intermediate zone. Image by Yves Jossin

develop properly, cells must coordinate their migratory patterns and the process by which they differentiate, or evolve from less-specialized cells into more-specialized cell types. A lack of such coordination leads to disordered development and, in some cases, cancer.

Jossin and Cooper set out to analyze how cells migrate in the cerebral cortex of the developing brain. The cerebral cortex, gray matter of the cerebrum, is the brain’s command and control center where cognition and planning occur, and it is particularly well developed in humans.

The cerebral cortex is composed of horizontal layers of nerve cells, or neurons, which are specialized for different functions and connected vertically into circuits. If some neurons are in the wrong layers, the wiring can be defective and neurological disorders including epilepsy, autism and schizophrenia may result.

In the fetus, the cortex grows "from the inside out" via the sequential addition of new neurons, which move from the inside, pass between neurons in previously established intermediate layers, and form new layers on the outside. How the migrations are regulated remains unclear despite years of study.

Jossin and Cooper now report the discovery of signals that control a particular stage in a cortical neuron’s journey. As new neurons initially move in a straight line from the inside to the outside, until they reach a layer called the intermediate zone, this zone contains relatively few neurons but many connecting fibers called axons. When new neurons reach the intermediate zone, they lose their way and start wandering - up, down, left and right, frequently changing direction. Then seemingly by chance, they emerge from the intermediate zone and realign to their original direction of movement, speeding ahead through layers of differentiated neurons towards the outer surface of the cortex.

The researchers aimed to determine how neurons get back on track after they emerge from the chaos of the intermediate zone. They identified a signaling protein, called Reelin, which is made by cells in the outermost layer of the cortex. It has been known for years that mutations in the Reelin gene cause profound cortical layering abnormalities in rodents and people, but it has been unclear which stage of neuron migration goes awry when Reelin is absent.

The new study shows that new neurons respond to Reelin as they emerge from the intermediate zone. "This is remarkable because the top layer of the cortex, where Reelin is made, is widely separated from the top of the intermediate zone, where it acts, so the Reelin protein must be diffuse," Cooper said. "It is also remarkable that Reelin seems not to be a direction signal itself. Rather, Reelin triggers changes in the membranes of the migrating neurons that allow the cells to respond to direction signals."

The researchers show that a membrane protein called N-cadherin increases on the surface of neurons when the neurons encounter Reelin. The surface increase in N-cadherin allows the cell to choose the appropriate direction for its next stage of migration. "This represents a new and surprising function for N-cadherin," Jossin said, "because normally this protein acts as a cellular stabilizer and not as an orchestrator of migration."

For example, elsewhere in the cortex, N-cadherin forms tight adhesions between adjacent cells and prevents them from moving. Indeed, the general role for cadherins in the body is to stabilize sheets of cells and organize tissues by holding cells together.

"The new role for N-cadherin in orienting migrating cells is quite unexpected and suggests that cadherins on the surface of other types of normal or cancer cells may also be involved in helping them move rather than stay in place," Jossin said. "This finding could provide new clues to how normal and cancerous cells migrate within the body," he said.

This research was funded in part by the National Institutes of Health and a Marie Curie Fellowship from the European Union.

To be published in Nature Neuroscience: "Reelin, Rap1 and N-Cadherin Orient the Migration of Multipolar Neurons in the Developing Neocortex."

At Fred Hutchinson Cancer Research Center, our interdisciplinary teams of world-renowned scientists and humanitarians work together to prevent, diagnose and treat cancer, HIV/AIDS and other diseases. Our researchers, including three Nobel laureates, bring a relentless pursuit and passion for health, knowledge and hope to their work and to the world. For more information, please visit www.fhcrc.org.

Original article: http://www.fhcrc.org/about/ne/news/2011/04/24/brain-cell-migration-development.html