At about four weeks, the heart begins to pump blood. Tiny limb buds appear, ankles and wrists are formed, and fingers and toes develop. During the first trimester, which lasts up to 10 weeks ...

Many four-legged animals go through embryonic stages that have similar features -- gill arches, a notochord, segmentation, and paddle-like limb buds -- as they develop into different adults.

By labeling and tracing cells in developing limb buds, the team was able to examine the patterns of tissue growth and deformation in space and time. They demonstrated that the patterns are so ...

Next week, she's the shape of a tiny tadpole and roughly the size of a pomegranate seed. Teeny limb buds are forming. Eventually, they'll become her arms and legs. Her eyes, mouth, and stomach are ...

We imaged the growth of these axons into the limb bud of day 10.5 embryos. Sensory axons, but rarely motor axons, were targeted to ectopically placed beads containing any of the neurotrophins NGF ...