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!



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.

 

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 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 Sept 8, 2014

Reproductive cycle of a plant. Arabidopsis thaliana.inside the diagram. Because of its relatively
short life cycle, Arabidopsis is a popular model organism in plant biology and genetics.
Image Credit: Mariana Ruiz LadyofHats for Wikipedia

 






WHO Child Growth Charts

 

 

 

Calcium and reproduction go together

Calcium is key to animal and plant fertilization. Everyone's heard of the birds and the bees. But that old expression leaves out the flowers — which are just as important.

Fertilization for flowering plants is complex due to the extensive communication signals between male and female reproductive cells. New research from an international team reports new discoveries in the chemical signaling process guiding flowering plant fertilization. Researchers are from Stanford, Regensburg, Heidelberg, and Munich, and include Carnegie's Wolf Frommer, David Ehrhardt, and Guido Grossmann with their being published in Nature Communications.


Flowering plants have a double fertilization system. Grains of pollen carry the male reproductive cells.

When pollen grains land on the flower's female reproductive organ, they germinate and grow towards the deeply embedded ovules via a pollen tube.

After fertilization, ovules develop into seeds.


What makes the process unique is that the pollen tube releases two sperm cells, one fuses with an egg in a process similar to that in animals. The other fuses with the so-called central cell to form a multi-nuclear entity that grows and provides nutrition for the first the developing embryo and then the seedling, in that order. This is the so-called endosperm, the major source of nutrition for the animals and humans that eat these plants.

Numerous cell-to-cell chemical interactions are needed to guide this process as it takes place, many of which remain unidentified.


In animals, calcium is key for communication between cells during fertilization.


The research team, led by Thomas Dresselhaus from the University of Regensburg and Guido Grossmann, who recently moved from Carnegie to the University of Heidelberg, focused on finding calcium-facilitated communication in the double fertilization of flowering plants.

It was already known that calcium is involved in the early stages of fertilization, including pollen tube growth and the guidance that brings the sperm to the ovule. But more work was needed to determine if it was as important in the later stages.


Using an advanced fluorescent calcium sensor the team was able to monitor calcium signatures in live cells throughout the whole double fertilization process.

The work was performed using Arabidopsis, a plant commonly used for research purposes. They found that calcium was involved in chemical signaling throughout the double fertilization process and is associated, for example, with sperm release and fusion with the egg cell.

This type of real-time observation had previously been impossible due to the deeply imbedded location where double fertilization occurs.


"Thanks to technical advances we were able to observe the moment of plant fertilization at the cellular level and, at the same time, listen to the 'tête-à-tête' between male and female cells," Grossmann added. "Further work is necessary to decode the language and understand what is actually being said."

Abstract
Cell–cell communication and interaction is critical during fertilization and triggers free cytosolic calcium ([Ca2+]cyto) as a key signal for egg activation and a polyspermy block in animal oocytes. Fertilization in flowering plants is more complex, involving interaction of a pollen tube with egg adjoining synergid cells, culminating in release of two sperm cells and their fusion with the egg and central cell, respectively. Here, we report the occurrence and role of [Ca2+]cyto signals during the entire double fertilization process in Arabidopsis. [Ca2+]cyto oscillations are initiated in synergid cells after physical contact with the pollen tube apex. In egg and central cells, a short [Ca2+]cyto transient is associated with pollen tube burst and sperm cell arrival. A second extended [Ca2+]cyto transient solely in the egg cell is correlated with successful fertilization. Thus, each female cell type involved in double fertilization displays a characteristic [Ca2+]cyto signature differing by timing and behaviour from [Ca2+]cyto waves reported in mammals.


This work was supported by the German Research Foundation DFG, the German Academic Exchange Service DAAD, an Emmy-Noether grant of the DFG, an EMBO long-term fellowship, the German Excellence Initiative, the U.S. Department of Energy, and the Carnegie Institution for Science. The Carnegie Institution for Science (carnegiescience.edu) is a private, nonprofit organization headquartered in Washington, D.C., with six research departments throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.


Return to top of page