Mesoderm, ectoderm and endoderm tissues in animal embryos grow into every organ the animal needs at birth, according to The Embryo Project Encyclopedia at Arizona State University. Collectively, scientists refer to these three layers of tissue as germ layers, and they form early in an embryo's life through a process called gastrulation.
The ectoderm forms outer parts of the body such as skin, hair, eyes, mammary glands and the spinal cord. When a part of the ectoderm folds inward, the neural tube grows in the embryo to create the central nervous system, parts of the face and the brain, according to Arizona State University.
The endoderm creates major organs such as the liver, pancreas, lungs and thyroid. The Biology Project from the University of Arizona explains that this germ layer also creates the mucosa lining of the digestive tract, tonsils and the inner layer of the lower urinary tract. The mesoderm grows into skeletal muscles, bones, connective tissues and the heart and forms the kidneys and the dermis of the skin.
LifeMap Sciences reveals that the three germ layers start to separate into distinct sections within the first three weeks of embryonic development. A small, spherical mass of cells rapidly forms the ectoderm, endoderm and mesoderm between day nine and day 21 of a human embryo's existence.Learn More
Skin regenerates by filling the gap between the sides of the cut with newly generated skin cells, starting with the dermis (bottom-most layer of the skin) and working its way up. Very shallow cuts are followed by easy regeneration, as only the stratum basale layer (the deepest layer of skin) of the epidermis (the outermost layer of the skin) is needed to generate enough cells to repair the damage.Full Answer >
Some bacteria manufacture and absorb their own food, while others must consume substances like living organisms or decaying material through their cell walls. Bacteria break down food in a process called respiration, which for some strains of bacteria requires oxygen to complete.Full Answer >
The rod shaped structures in the nucleus of a cell are chromosomes. They carry genetic material in a "rod" of DNA that is bonded to various proteins in the cell nucleus.Full Answer >
RNA, or ribonucleic acid, has ribose as its sugar. Ribose has five carbon atoms and is called a pentose sugar. DNA, or deoxyribonucleic acid, also contains a pentose sugar, deoxyribose, but its sugar has one less carbon atom than ribose.Full Answer >