Welcome to The Visible Embryo
Home-- -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- -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

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.


Pregnancy Timeline by SemestersLungs begin to produce surfactantImmune system beginningHead may position into pelvisFull TermPeriod of rapid brain growthWhite fat begins to be madeHead may position into pelvisWhite fat begins to be madeImmune system beginningBrain convolutions beginBrain convolutions beginFetal liver is producing blood cellsSensory 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 ON weeks 0 - 40 and follow along every 2 weeks of fetal development
Google Search artcles published since 2007

Home | Pregnancy Timeline | News Alerts |News Archive Mar 9, 2015

Mitochondrial DNA (mtDNA) produces a "short open reading frame" or sOR, and may
contain others. This particular sORF encodes a signaling peptide named MOTS-c.
When given to mice, MOTS-c prevented age-dependent and high-fat-diet-induced insulin
resistance — suggesting mitochondria may regulate metabolic stability in the cell.
Image Credit: Cell Metabolism




New hormone mimics the effects of exercise

A new human hormone, MOTS-c, has just been identified that protects against obesity and diabetes. The research was done in mice, but the chemistry exists in all mammals. MOTS-c was found in mitochondrial DNA while other hormones are produced in the DNA nucleus. It primarily targets muscle tissue, where it surprisingly restores insulin sensitivity.

Scientists at the USC Leonard Davis School of Gerontology have discovered a new hormone that fights weight gain caused by a high-fat Western diet, and results in a normalized metabolism - commonly found only with exercise.

Hormones are molecules that act in the body as signals to trigger various physiologic responses. The newly discovered hormone, MOTS-c, primarily targets muscle tissue where it restores insulin sensitivity, counteracting diet-induced and age-dependent insulin resistance.

"This represents a major advance in the identification of new treatments for age-related diseases such as diabetes," said Pinchas Cohen, dean of the USC Davis school and senior author of a study on the research, which will appear in Cell Metabolism on March 3.

Until this discovery, the main function of mitochondria was seen as the production of adenosine triphosphate (ATP), a cell's energy source.

To test the effects of MOTS-c, the team injected the hormone into mice fed a high-fat diet, which typically causes them to grow obese and develop a resistance to insulin. However, the injections not only suppressed both effects in mice, they also reversed age-dependent insulin-resistance, a condition that precedes diabetes.

"This discovery sheds new light on mitochondria and positions them as active regulators of metabolism," said Changhan Lee, assistant professor at USC Davis and lead author of the study.

MOTS-c is unique among hormones as it is encoded in the DNA of mitochondria — the "powerhouses" of cells where food calories are converted into energy. Other hormones are encoded in DNA in the cell nucleus.

Lee and Cohen collaborated with scientists from the USC school as well as the David Geffen School of Medicine at UCLA and the National Institutes of Health. While all of the experiments on MOTS-c so far have been performed on lab mice, the molecular mechanisms that make it function in mice exist in all mammals, including humans.

The MOTS-c intellectual property has been licensed to a biotechnology company, and clinical trials in humans could begin within the next three years, added Pinchas Cohen, dean of the USC Davis school and senior author.

MOTS-c, a mitochondrially encoded open reading frame-derived peptide recently discovered by Lee et al. 2015 (this issue of Cell Metabolism) promotes biosynthesis of an endogenous AMP analog, AICAR. As AICAR activates AMPK, the discovery of MOTS-c offers an unexpected therapeutic option to be exploited toward the prevention of type 2 diabetes and delaying of the aging processes.

This research was funded by National Institutes of Health (grants 1R01AG 034430 EUREKA Award, 1R01GM 090311 Transformative RO1, 1R01ES 020812), a Glenn Award, an Ellison Medical Foundation New Scholar Award, and a SC-CTSI grant.

Return to top of page





Mitochondia breaks down nutrients and creates energy for the cell.