Activity: Specimen Viewing on the Digestive System’s Components 🔬🧐

[1] Large Intestine Human c.s.

Structure: The colon, rectum, anus, and caecum are the four main divisions of the large intestine. The ileocecal valve regulates the movement of chyme from the small intestine into the large intestine and it is situated at the opening between the ileum and the large intestine. The appendix to the anus is where the large intestine ends. The small intestine is framed on three sides by it. It is named large even though it is only half as long as the small intestine because it has a diameter of around three inches, more than twice that of the small intestine.

Function: The alimentary canal’s terminal segment is the large intestine. This organ’s major functions include completing the body’s absorption of water and nutrients, synthesizing particular vitamins, generating feces, and removing them from the body.

[2] Ileum Human c.s

Structure: The ileum, which is approximately 1.8 meters (6 feet) long, is the longest segment of the small intestine. Compared to the jejunum, it is thicker, more vascular, and has more developed mucosal folds. At the ileocecal sphincter (or valve), the ileum connects to the caecum, which is the first segment of the large intestine.

Function: Food that has passed through the stomach and other sections of the small intestine is further broken down by the ileum. It absorbs any remaining nutrients, with the primary absorptive products generated such as bile acids and vitamin B12.

[3] Human Stomach-Cardiac c.s.

Structure: The stomach is divided into four main sections: the cardia, fundus, body, and pylorus. Food enters the stomach through the cardia, also known as the cardiac region, which is the junction of the esophagus and stomach. The dome-shaped fundus is situated above and to the left of the cardia, inferior to the diaphragm. The stomach’s primary portion, the body, is located beneath the fundus. The duodenum and stomach are joined by the funnel-shaped pylorus. The pyloric antrum, the funnel’s broader end, joins the stomach’s body. The pyloric canal, on the other hand, which joins the duodenum, is the narrowest end. At this final junction, the smooth muscle pyloric sphincter regulates the process of emptying the stomach. In addition, the stomach shrinks inward in the absence of food, causing the mucosa and submucosa to collapse into a sizable fold known as a ruga.

Function: Storing and breaking down the food and liquids that are consumed during meals is the stomach’s primary function. In order to aid in the digestion of food and other foreign materials like bacteria, it creates hydrochloric acid and enzymes. Such unwanted microbes are killed by the stomach’s acidic environment. Additionally, it aids in digestion by contracting its muscles at regular intervals to churn the food swallowed.

[4] Caecum c.s.

Structure: The caecum, a sac-like structure hanging inferior to the ileocecal valve, is the first portion of the large intestine. It takes in the contents of the ileum and continues to absorb salts and water. It is roughly 6 cm (2.4 in) in length.

Function: The two primary purposes of the caecum are the microbial digestion of soluble and insoluble carbohydrates prior to their entry to the ascending colon and the absorption of substantial amounts of water and electrolytes.

[5] Frog Small Intestine c.s.

Structure: The small intestine of a frog can be found in numerous loops supported by the mesentery, which is a membrane that resembles a fan. The duodenum is the portion of the small intestine that curves upward to create a U with the stomach, and the coiled ileum makes up the remaining portion of it. The pancreas and liver provide the pancreatic and bile juice to the duodenum through an opening known as the common hepatopancreatic duct. And the low transverse folds in the small intestine contain the inner mucous lining, which contains the goblet and absorbing cells.

Function: The small intestine’s primary roles include breaking down food, absorbing nutrients the body needs, and eliminating waste.

References:

Lumen Learning. (n.d.). The Small and Large Intestines. https://courses.lumenlearning.com/suny-ap2/chapter/the-small-and-large-intestines/

Collins, J. T., Nguyen, A., & Badireddy, M. (2023). Anatomy, Abdomen and Pelvis, Small Intestine. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459366/

Lumen Learning. (n.d.). The Stomach. https://courses.lumenlearning.com/suny-ap2/chapter/the-stomach/

BYJU’S. (n.d.). Digestive System of Frog. https://byjus.com/neet/digestive-system-of-frog/