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This interrupted case study explores the role of cytoskeletal structures on human health, specifically on respiratory function, sperm motility, and female fertility. It follows the story of a couple struggling to conceive a child and the doctors working to help them. Students are presented with clinical histories, narrative elements, documentary-style videos, and microscopic evidence in order to determine the cause of the couple's infertility. Along the way, they learn about the three types of cytoskeletal elements and the roles these play in cellular biology and human physiology. The use of videos makes it suitable for the "flipped classroom," allowing students to prepare outside the classroom for the case study, which they then complete in class. An original video by the author on the structure and function of microtubules, microfilaments, and intermediate filaments is included. The case was developed for an introductory level general biology course and could be delivered during a unit on the cell structure and function. The case could also be used in a cell biology course.

Mouse study fingers potential cause of fertility problems, proposing obesity and egg quality link.

Researchers have long known that women whose families include fraternal twins are more likely to give birth to twins themselves, and they're finally starting to figure out why. After scanning data from nearly 2000 mothers of fraternal twins, scientists from eight countries found two genes that increase a woman's chance of having twins-one that affects hormone levels and another that may alter how ovaries respond to them. The second of these may also have implications for why some women respond better than others to in vitro fertilization.

Sulston worked alone, in silence, hunched over a microscope for eight hours a day. By studying and drawing worms of various ages, he figured out the ancestor and descendants of each of their cells. It was a monumental piece of science. Sulston mapped the complete history of an individual, the comprehensive family tree of a single body. "We had the entire story of the worm's cells from fertilized egg to adult," he later said, upon accepting the Nobel Prize for his work.

The Visible Embryo is a visual guide through fetal development from fertilization through pregnancy to birth. As the most profound physiologic changes occur in the "first trimester" of pregnancy, these Carnegie stages are given prominence on the birth spiral.

This page shows some key events of human development during the embryonic period of the first eight weeks (weeks 1 - 8) following fertilization. This period is also considered the organogenic period, when most organs within the embryo have begun to form. There are links to more detailed descriptions which can be viewed in a week by week format, by the Carnegie stages or integrated into a Timeline of human development. Online resources available include: individual images of all Carnegie stages, scanning electron micrographs of the earlier stages, cross-sections showing internal structures at mid- and late-embryonic, 3D reconstructions of internal structures, animations of processes, ultrasound scans and information about abnormalites of development.

The early stages of embryonic development shape our cells and tissues for life. It is during this time that our newly formed cells are transformed into heart, skin, nerve or other cell types. Scientists are finding that this process is largely controlled not by the genome, but by the epigenome, chemical markers on DNA that tell cells when to turn genes on and off. Now, studying zebrafish embryos, researchers at Washington University School of Medicine in St. Louis have shown that the epigenome plays a significant part in guiding development in the first 24 hours after fertilization.

2014 was a banner year for making automotive fuel from nonfood crops, with a series of major new production plants opening in the United States. However, producing this so-called cellulosic ethanol remains considerably more expensive than gasoline. So researchers are always on the lookout for new ways to trim costs. Now they have a new lead, a microbe that can use abundant nitrogen gas as the fertilizer it needs to produce ethanol from plants.

Understanding the variability in human hair isn't only interesting from a cosmetic perspective-it also informs the study of evolution. Hair can signal social status, health and fertility, and regulates body temperature.

A kind of salmon that's been genetically modified so that it grows faster may be on the way to a supermarket near you. The Food and Drug Administration approved the fish on Thursday - a decision that environmental and food-safety groups are vowing to fight. This new kind of fast-growing salmon was actually created 25 years ago by Massachusetts-based AquaBounty Technologies. A new gene was inserted into fertilized salmon eggs - it boosted production of a fish growth hormone. The result: a fish that grows twice as fast as its conventional, farm-raised counterpart.

This two-minute video provides brief background on the use of zebrafish as a model in studying animal development, before showing a time-lapse sequence of a fertilized zebrafish egg developing into a larva.  The video includes some annotations that help orient the viewer during the time-lapse sequence.  Teachers might want to mute the narration beginning at 0:42 min to avoid giving students too much information.  This phenomenon could stimulate the following driving questions: How does the zebrafish develop from one cell to the many cells that make up the larva? How do the zebrafish cells divide? How are the developing zebrafish cells similar and different from each other? If all cells in the zebrafish develop from the same original cell, then how do some cells develop differently than others? How are cell division and growth related? 

For the first time in modern history, the world's population is expected to virtually stop growing by the end of this century, due in large part to falling global fertility rates, according to a Pew Research Center analysis of new data from the United Nations. By 2100, the world's population is projected to reach approximately 10.9 billion, with annual growth of less than 0.1% - a steep decline from the current rate. Between 1950 and today, the world's population grew between 1% and 2% each year, with the number of people rising from 2.5 billion to more than 7.7 billion.

Why do we smell different when we're sick? Why does cheese smell like feet? Why don't vultures get sick from eating rotting meat? Science is filled with stories: some of them are beautiful and some of them are gross. Really gross. Gross Science, a YouTube series hosted by Anna Rothschild, tells bizarre stories from the slimy, smelly, creepy world of science. In this collection, you'll find original short-form videos and DIY experiments from Gross Science, which is produced by NOVA and PBS Digital Studios. Learn about amphibians that eat their mother's skin, strange uses for bacon, how poop can be used to cure an infection, and more gross science topics.

First, surgeons remove the uterus and part of the vagina from the donor - in this case, one who was deceased, since it is a risky surgery that involves separating uterine blood vessels that are tightly wrapped around the tubes from the bladder. Next, the uterus is transferred to the living recipient. Surgeons connect an artery and a vein on either side of the uterus to connect it to the recipient's blood supply. A piece of the donor's vaginal tissue is attached to the recipient's vagina, and supporting tissue is attached to the pelvis to secure the organ in place. It's not necessary to connect any nerves.

Will men be able to give birth sooner than, well, never? (Credit Yahoo Health/iStock) That's the question provoked by last week's announcement that the Cleveland Clinic is performing uterus transplant surgery on women who were born without a womb or whose uterus is diseased or malfunctioning. Hearing the news, we, and some of you, wondered: If science can transplant a uterus into a woman, can it transplant one into a man?

IN recent weeks, two major medical organizations have issued independent warnings about toxic chemicals in products all around us. Unregulated substances, they say, are sometimes linked to breast and prostate cancer, genital deformities, obesity, diabetes and infertility. "Widespread exposure to toxic environmental chemicals threatens healthy human reproduction," the International Federation of Gynecology and Obstetrics warned in a landmark statement last month.

Digital resources using sea urchins to engage across topics