Introduction
The purpose of this paper is to provide a comprehensive description of the stomach and the digestive system. The stomach is a muscular organ inferior to the diaphragm and superior to the small intestine. It is also anterior to the pancreas and lateral to the spleen. Points such as the anatomical and microscopic description of the organ, its functions, homeostasis, diseases, and its relationship to the nervous system are addressed in this study.
Anatomical Description
To most people, the stomach is a uniform organ made of some tissue and generally reminiscent of a bag in the way it is shaped. To the medical professionals, however, it is substantially more complicated than that. The main structure of the stomach consists of four segments: the cardia, the fundus, the corpus or body, and the antrum (Landa et al., 2019). The cardia is the region of the stomach directly neighboring the gastroesophageal junction. Next is the fundus, which is the highest part of the stomach. Below that, is the corpus – the largest area of the stomach, contained between the lesser curvature and the greater curvature. Finally, between the corpus and the pylorus is the antrum, the last part of the stomach before the pyloric sphincter that separates it from the small intestine.
Microscopic Description
The stomach’s microscopic structure is complex, constituted of multiple layers of tissue. The stomach wall is comprised of four layers: the mucosa, submucosa, muscularis externa, and the serosa (Chaudhry et al., 2019). The first layer from the inside is the mucosa, which consists of gastric glands covered by epithelial tissue. A recent study suggests that stem cells can be found at the base of these glands (Wright, 2016). The main component of the submucosa, which is the next layer, is dense connecting tissue that supports the next layer of muscular tissue – the muscularis externa. The outer layer of muscle tissue contains three layers: longitudinal, oblique, and circular.
Functions of the Organ
The function of the stomach is to hold large quantities of food and prepare it for further digestion in the intestines. The muscles at the top of the stomach can relax to provide space for the food that enters. The organ produces stomach juices that are necessary for chemical digestion. The bottom part of the stomach can assist in mixing and breaking down the food by contracting its muscular wall structure (Chaudhry et al., 2019). When the food is sufficiently processed, it is allowed to pass to the intestines in small portions.
Homeostasis
The role of the stomach for homeostasis extends beyond providing nutrients. The importance of the digestive system’s primary function cannot be understated, as human beings require the proteins, fats, minerals, and vitamins extracted from the food they consume to sustain themselves. The digestive system is also responsible for producing hormones that regulate the digestion process. In addition to that, the stomach also contains gastric stem cells that are crucial to human body development and homeostasis (Willet & Mills, 2016). Finally, the stomach contributes to the immune homeostasis through its lymph nodules.
Prediction
There are severe potential consequences if the stomach fails to maintain homeostasis. The most apparent possible fault that can occur is with the digestion process. If the stomach is unable to process food properly, a person could experience weakness, lack of energy, and weight loss. On the opposite end of the spectrum, a problem with a particular hormone could lead a person to feel perpetually hungry, which in turn may cause obesity and many other health issues.
Disease
One of the most well-known conditions that affect the stomach is gastritis. The disease can be caused by a bacteria Helicobacter pylori that infects the organism (Protheroe, 2017). It may also arise from excessive use of alcohol, stress, vomiting, and taking certain types of medicine. The symptoms include nausea, abdominal pain, vomiting, indigestion, loss of appetite, and black excrements. Gastritis can be diagnosed through an upper endoscopy, a blood test, or a stool test. The disease itself is characterized by inflammation of the inner tissues of the stomach that could lead to ulcers if not treated. Luckily, maintaining a correct diet and receiving timely medical assistance leads to quick improvements for most people.
Relationship to the Nervous System
The stomach is closely connected with the nervous system, which it needs to regulate its inner processes. The term used to describe the network that controls the intricate functions of the bowel is the enteric neural system or ENS. The ENS consists of over 500 million neurons that form layers in the stomach wall (Schneider et al., 2019). The functions of the ENS are vast, as it manages bowel movement, blood flow, and epithelial secretion (Schneider et al., 2019). It also affects the immune system and epithelial proliferation and repair (Schneider et al., 2019). Overall, the enteric nervous system is a fascinating part of the human body, and some even call it the second brain. The relationship of the ENS with the digestive system is extremely close, as one structure exists to complement the other.
References
Chaudhry, S. R., Liman, M. N. P., & Peterson, D. C. (2019). Anatomy, abdomen and pelvis, stomach. NCBI. Web.
Landa, S. T., Dumon, K. R., & Dempsey, D. T. (2019). Anatomy and physiology of the stomach and pylorus. In J. Grams et al. (Eds.), The SAGES manual of foregut surgery (pp. 49-64). Springer.
Protheroe, S. (2017). Systemic disease affecting the stomach. In H. Till et al. (Eds.), Esophageal and gastric disorders in infancy and childhood (pp. 1425-1445). Springer.
Schneider, S., Wright, C. M., & Heuckeroth, R. O. (2019). Unexpected roles for the second brain: Enteric nervous system as master regulator of bowel function. Annual review of physiology, 81, 235-259.
Willet, S. G., & Mills, J. C. (2016). Stomach organ and cell lineage differentiation: From embryogenesis to adult homeostasis. Cellular and molecular gastroenterology and hepatology, 2(5), 546-559.
Wright, N. (2016). The gastric epithelium: Slow starter in the stem cell/lineage specification stakes? Cellular and molecular gastroenterology and hepatology, 2(5), 538-539.