HUMAN NUTRITION 3 2
Layers of the gastrointestinal tract
There are four layers of the gastrointestinal tract, which are responsible for different
functions of digestion. The layers are composed of associated tissues that facilitate the general
function of each layer. The four layers are mucosa, submucosa, muscularis, and serosa. First and
foremost, Mucosa is regarded as the layer comprising of simple epithelial cells and thin
connective tissue. The epithelium layer is the innermost part of the goblet and endocrine cells
(Johnson, 2012). The other layer is lamina propria, which is situated at the outer part of the
epithelium and is termed as the connective tissue. The outer layer of the mucosa is referred to as
the muscularis mucosae, which is a thin and smooth muscle that generates local movements.
Connective tissue absorbs the digested products from the lumen and protects GIT from bacteria
and other pathogens. They also increase the surface area of absorption (Gregersen, 2003).
Secondly is the submucosa found in the outer region of the mucosa. This layer is
composed of connective tissue with lymphatic vessels, nerve fibers, and blood vessels. It is thick
and highly vascularized to serve the mucosa by picking the absorbed materials through its blood
vessels (Gregersen, 2003). The third layer is the muscularis, which has muscles at the mouth and
pharynx that are responsible for swallowing food. At the other length of the layer, it consists of
smooth muscles and associated nerve fibers involved in the movement of food and mechanical
digestion. The fourth layer is the serosa, which is the membrane covering the muscularis of the
digestive tract. It secretes serous lubricating fluid (Johnson, 2012).
Challenges of Crohn’s disease
Various challenges are facing an individual with Crohn’s disease. The problems are
associated with frequent visits to the healthcare facility to seek help. Various medical tests are
carried out and are followed by medications that are linked to many side effects ("Crohn
