Christopher D. Morgan
Trident University International
COURSE NAME AND NUMBER: ANT250_II Anatomy and Physiology II
Module 2: Case Assignment
PAPER NAME: The Anatomy of Digestive System
INSTRUCTOR NAME: Dr. Terry Ann Else, PhD
DATE: 14 August 2015
A nice well-prepared meal is very important. Ideally, meals should be taken thrice a day that is breakfast, lunch then supper. Eating makes the body stronger and helps it to actively engage in day-to-day activities productively (Bobick & Balaban. 2009)
According to Bobick & Balaban ( 2008), all the moments after having a meal, physiological and chemical reactions always occur in different parts of the body organs and glands, the digestive system. A number of enzymes and organs work collectively to break down the food initially passed on to the mouth where digestion begins, the energy that is produced is later used to perform other body functions.
Anatomy of digestive system
As Bobick & Balaban( 2008) put it, digestive system is divided into two: alimentary canal and accessory digestive organs. Alimentary canal is a pipe in which food passes, it starts from the mouth, oesophagus, stomach, intestines then finally ends at the anus. The alimentary canal helps in food ingestion, absorption and defecation.
Accessory digestive organs are the teeth, tongue and other large digestive glands, which help in the breakdown of food in the mouth. In the mouth, the food is mixed with saliva then chewed, the tongue makes it easy for the food to be swallowed, and this is where the digestion of food starts then passes on to the pharynx, which is a muscular tube that extends to the oesophagus. It provides air for the food, as the food passes, it contracts as the food is pushed to oesophagus which connects to the stomach, it conducts the food by peristalsis to the stomach which is a C-shaped organ located on the left side of the abdominal cavity. The food enters the stomach through cardioesopageal sphincter, then to the small intestine through pyloric sphincter. The food is then mixed by help of an oblique layer of muscle. (Bobick & Balaban, 2009).
As discussed by Bobick & Balaban ( 2008), the presence of mucus protects the inner lining of the stomach from being digested. The food is held temporarily in the stomach before being moved to the small intestines, which is a tube like structure containing duodenum, jejunum and ileum where major digestion takes place. Food absorption and digestion are completed in the small intestine. The ileum, the third or last part of the small intestine joins the large intestine, which is much bigger than the small intestine it is divided into caecum, appendix and anal canal that ends in the anus. The large intestine dries out indigested food residue by absorbing water and gets rid of them from the body as faeces through the anal canal that connects to the anus.
Metabolism
Life in general is maintained by all the chemical reactions taking place in the body. It involves the process of catabolism and anabolism. Catabolism is whereby the living cells are broken down into simpler substances, where as anabolism involves energy required to combine simpler substances to form complex substances in which larger molecules are built (Bobick & Balaban, 2008). .
Bobick & Balaban (2008) further discussed that chief cells are located near the base of the glands and are protein-secreting cells. Pepsinogen and a weak lipase are the ones secreted by the chief cells. Pepsinogen is converted to the proteolytic enzyme pepsin upon contact with the acidic gastric juice. Enteroendocrine also cells are more prevalent near the base but can be found anywhere in the glands. Argentaffin cells secrete their product into the lamina propria whence it is taken up by blood vessels. Major secretory product of the enteroendocrine cells is gastrin, which stimulates the production of Hydrochloric Acid. Other secretions are glucagon and serotonin. Parietal cells are located in the gastric glands in fundus’lining found in the body of the stomach, they are epithelial cells, which secrete Hydrochloric acid and intrinsic factor, and undifferentiated cells are located in the neck region and give rise to all the other cell types. They are low columnar cells and are few in number. They travel upwards to replace surface mucous cells whose lifespan is three-5 days, and downward to replace parietal, chief and enteroendocrine cells.
Bobick & Balaban (2008) concluded that digestive system and body metabolism is a series of tasks that begins when food is put in the mouth then eliminated through the anus.
References
Bobick, J and Balaban, N (2009) Digestive System
James B, Naomi B (2008) Handy Anatomy Answer book. Visible Ink Press. MI USA
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