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 s

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.