BIO-TALKS

THE ORIGINS OF THE MAJOR ORGANS-The pancreas, liver, and gallbladder begin as a second single tube that grows off the small intestine, just below the stomach.

THE ORIGINS OF THE MAJOR ORGANS-The respiratory and digestive systems arise from a single tube that begins to form very early in human development, about 16 days after fertilization of the egg. Different regions of the tube or buds that sprout along its sides eventually become the stomach, lungs, liver, and several other organs.

THE ORIGINS OF THE MAJOR ORGANS- Organs form according to the same basic principles. The aim of this chapter is to give a taste of how developmental biologists study the very complex rearrangements of cells that create tissues.