Welcome to The Visible Embryo
The Visible Embryo Home
Home--- -History-----Bibliography-----Pregnancy Timeline-----Prescription Drugs in Pregnancy---- Pregnancy Calculator----Female Reproductive System----News----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 one million visitors each month.

Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human. The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.

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!




Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System


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.


Pregnancy Timeline by SemestersDevelopmental TimelineFertilizationFirst TrimesterSecond TrimesterThird TrimesterFirst Thin Layer of Skin AppearsEnd of Embryonic PeriodEnd of Embryonic PeriodFemale Reproductive SystemBeginning Cerebral HemispheresA Four Chambered HeartFirst Detectable Brain WavesThe Appearance of SomitesBasic Brain Structure in PlaceHeartbeat can be detectedHeartbeat can be detectedFinger and toe prints appearFinger and toe prints appearFetal sexual organs visibleBrown fat surrounds lymphatic systemBone marrow starts making blood cellsBone marrow starts making blood cellsInner Ear Bones HardenSensory brain waves begin to activateSensory brain waves begin to activateFetal liver is producing blood cellsBrain convolutions beginBrain convolutions beginImmune system beginningWhite fat begins to be madeHead may position into pelvisWhite fat begins to be madePeriod of rapid brain growthFull TermHead may position into pelvisImmune system beginningLungs begin to produce surfactant
CLICK ON weeks 0 - 40 and follow along every 2 weeks of fetal development


Do chemicals make us couch potatoes?

A University of Missouri study has found that when pregnant mice are exposed to environmental chemicals, their daughters have a decreased metabolism expressed as a lack of physical activity conducted later in life.

Endocrine disruptors contaminate and interfere with our hormones. They can cause tumors, birth defects and developmental disorders in mammals. And often, we find them in a variety of our consumer products, such as water bottles, dental fillings, and resins used to line metal food and beverage containers.

Now, a University of Missouri study finds strong evidence that these disruptors are essentially creating "couch potatoes" among female mice and could predict more metabolic complications. The work is published in the Journal of Developmental Origins of Health and Disease, Cambridge University Press, September 2015.

"We found that if we exposed mice to one of two common endocrine disruptors — bisphenol A (BPA) or ethinyl estradiol (EE), the estrogen in birth control pills — during development of the fetus, it later caused disruptions in voluntary physical activity once the mice became adults. Mice exposed to endocrine disruptors move around less, are more likely to sleep and engage in less voluntary physical activity."

Cheryl Rosenfeld PhD, Associate Professor of Biomedical Sciences, College of Veterinary Medicine, researcher in the Bond Life Sciences Center at University of Missouri.

To test the chemicals' impact on metabolism and activity, Rosenfeld's lab exposed mice to BPA and EE in the womb and during weaning through the mother's diet. A third group of mice whose mothers were placed on a control diet and were thus not exposed to either chemical. At weaning, the scientists then placed all the mice on the same control diet and measured their energy expenditure, body composition and level of voluntary physical activity as adults.

To further test the effects of voluntary exercise, the lab rigged bicycle computers to "hamster wheels" to track how far, fast and for how long the mice ran. Researchers monitored the mice's energy expenditure by measuring oxygen consumption and carbon dioxide production, and tracked the rodents' movements during the day and at night.

"Female mice exposed to BPA and EE were less active than the control mice. They moved around less at night — when mice are typically most active — and moved more slowly, drank less water, and spent more time sleeping.

"In addition, BPA-exposed females burned more carbohydrates relative to fats, as compared to control mice. This is similar to the difference between obese and slender humans, and many researchers believe that burning more carbohydrates relative to fats can lead to fats gradually accumulating in the body."

Cheryl Rosenfeld PhD, associate professor of biomedical sciences, College of Veterinary Medicine and Bond Life Sciences Center at University of Missouri.

The researchers currently are conducting follow-up studies to determine if the changes caused by exposure to BPA and EE predispose mice to obesity and other metabolic disorders.

"Our findings are significant because decreased voluntary physical activity, or lack of exercise, can predispose animals or humans to cardiovascular diseases, metabolic disorders and even cancer," Rosenfeld adds.

Endocrine disrupting chemicals (EDC) have received considerable attention as potential obesogens. Past studies examining obesogenic potential of one widespread EDC, bisphenol A (BPA), have generally focused on metabolic and adipose tissue effects. However, physical inactivity has been proposed to be a leading cause of obesity. A paucity of studies has considered whether EDC, including BPA, affects this behavior. To test whether early exposure to BPA and ethinyl estradiol (EE, estrogen present in birth control pills) results in metabolic and such behavioral disruptions, California mice developmentally exposed to BPA and EE were tested as adults for energy expenditure (indirect calorimetry), body composition (echoMRI) and physical activity (measured by beam breaks and voluntary wheel running). Serum glucose and metabolic hormones were measured. No differences in body weight or food consumption were detected. BPA-exposed females exhibited greater variation in weight than females in control and EE groups. During the dark and light cycles, BPA females exhibited a higher average respiratory quotient than control females, indicative of metabolizing carbohydrates rather than fats. Various assessments of voluntary physical activity in the home cage confirmed that during the dark cycle, BPA and EE-exposed females were significantly less active in this setting than control females. Similar effects were not observed in BPA or EE-exposed males. No significant differences were detected in serum glucose, insulin, adiponectin and leptin concentrations. Results suggest that females developmentally exposed to BPA exhibit decreased motivation to engage in voluntary physical activity and altered metabolism of carbohydrates v. fats, which could have important health implications.

Sarah A. Johnson, a graduate student in Rosenfeld's lab, Charles Wiedmeyer, an associate professor in the Department of Veterinary Pathobiology in College of Veterinary Medicine at MU, and John Thyfault, an associate professor of molecular and integrative physiology at the University of Kansas Medical Center, collaborated on the study.

Editor's Note: For more on this story, please see: https://decodingscience.missouri.edu/2015/09/18/chemicals-and-couch-potatoes/

The study was supported by the National Institutes of Health NIH (Grants 5R21ES023150 and R01DK088940). The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agencies.

For a video on this story, please see: https://www.youtube.com/watch?v=P11GSN55AnI

Return to top of page

Sep 28, 2015   Fetal Timeline   Maternal Timeline   News  News Archive   

Image Credit: Rosenfeld lab, University of Missouri
For a video on this story, please see: https://www.youtube.com/watch?v=P11GSN55AnI











Phospholid by Wikipedia