The appendix is that one organ that has been claimed to have no known function, but a new study finds out it the opposite. A study from Midwestern University shows that the appendix is involved in immune function and nurturing of the human microbiome. It serves as an important role in the fetus and young adults.”
Heather F. Smith, Ph.D., from the Midwestern University Arizona College of Osteopathic Medicine, took more than 500 mammal species in her study. It was found that not every species had an appendix. The research focused on gastrointestinal traits to determine why some animals have an appendix, and others don’t, to find the true nature of the appendix could be realized.
They found out that the appendix had evolved independently over 30 different times in multiple distinct mammal lineages. Once the appendix evolved, it rarely disappeared, implying an adaptive purpose that continued to be naturally selected for overtime.
While the researchers investigated multiple ecological factors, including diet, climate, sociability, and habitat of each mammalian species, the results led them to ultimately reject the idea of the appendix associated with dietary or environmental factors.
Instead of that, they strongly support that the appendix plays an important role as a secondary immune organ, similar to the lymph nodes, tonsils, spleen, Peyer’s patches, and mucosa-associated lymphoid tissue (MALT). They have concluded that mammalian species with an appendix had higher average concentrations of immune tissue in the cecum, a pouch marking the beginning of the large intestine. The appendix is also connected to the large intestine.
In addition to its various roles in the immune response, immune tissue, appendix, also promotes the growth of many species of “good” gut bacteria. Previous researches have also linked the appendix to roles in the body, such as the production of biogenic amines and peptide hormones from the fetal appendix and the production of immunoglobulin A antibodies.
Smith’s study indicates a more complex role of the appendix in the body of humans and other mammals, especially highlighting its union with the cecum.
Like any other organ, the appendix can also get infected. However, this organ seems to be especially prone to infection, infamously known as appendicitis. This condition is considered a medical emergency, most commonly occurring in individuals between 10 and 30 years old. The infection is caused by a blockage inside of the organ that leads to increased pressure, blood flow obstruction, and inflammation. If left untreated, the appendix can burst and spread the infection into the abdomen, causing a potentially lethal condition called peritonitis.
More than five percent of the population experiences appendicitis at some point. And the More often than not, appendicitis causes the removal of the organ. So with a new understanding of the role of the appendix in the immune system and the microbiome, researchers might next consider investigating the effect on the body when an appendix goes “missing.”