What is Gastrulation?
Gastrulation is the process through which stomach acids break down food into smaller pieces. When digestion takes place, small amounts of nutrients are absorbed from the food. These nutrients are then used to build up your body’s reserves or energy. You may have heard that gastric juices contain vitamins A, B1, B2, C and E. They are very important in human health.
The digestive system consists of two parts: the mouth and the stomach. The mouth breaks down food through chewing, and the stomach continues the process of breaking down food through gastrulation.
The cells of the stomach contain a large number of tiny, spear-like enzymatic molecules. These break down proteins, starches, and fats into their respective amino acids, monosaccharides, and disaccharides. This continues the process of digestion until all that is left is a watery fluid called chyme.
Chyme is then sent to the small intestine, where most of the water is absorbed back into the body. The small intestine is covered with tiny, finger-like projections called villi, and microvilli on the surfaces of these.
This increases the total area for absorption. Nutrients are absorbed through the walls of the small intestine and into the blood stream. The leftover waste material is then sent to the colon and finally out of the body in the form of feces.
The process of gastrulation is an on-going and natural part of life. It is essential for the continued survival and well-being of all organisms.
Gastrulation is a complex process in which cells differentiate and organize themselves into distinct layers and parts of the stomach. The process involves the formation of a disc (a structure that develops in the embryo) called the “primitive streak” from which cells are ‘educated’ into becoming stomach cells.
The process of gastrulation in humans takes place at week 2 to week 3 (day 14 to day 18) in an embryo’s development.
From the primitive streak, cells differentiate into two layers: the endoderm and the mesoderm. The endoderm eventually forms the lining of the stomach and portions of the intestines.
The mesoderm is the foundation for muscles, blood, and other connective tissues.
During gastrulation, cells known as “na?
ve” or “pre-stomach” cells migrate from the epiblast (primitive exterior of the embryo) to the area of the primitive streak through a structure known as the yolk plate. (The yolk plate consists of material that was in the egg before the embryo began to develop. It lies in between the epiblast and the hypoblast (primitive internal mass). It is eventually absorbed into the embryo by the cells of the epiblast moving outward.
Sources & references used in this article:
- Cell migration during gastrulation (R Keller – Current opinion in cell biology, 2005 – Elsevier)
- Gastrulation: making and shaping germ layers (L Solnica-Krezel, DS Sepich – Annual review of cell and …, 2012 – annualreviews.org)
- Dishevelled controls cell polarity during Xenopus gastrulation (JB Wallingford, BA Rowning, KM Vogeli, U Rothbächer… – Nature, 2000 – nature.com)
- How we are shaped: the biomechanics of gastrulation (R Keller, LA Davidson, DR Shook – Differentiation: ORIGINAL …, 2003 – Wiley Online Library)
- Silberblick/Wnt11 mediates convergent extension movements during zebrafish gastrulation (CP Heisenberg, M Tada, GJÈ Rauch, L Saúde… – Nature, 2000 – nature.com)