Week 11 - Organ System Connections

 I would choose about the skin should be considered an immune system organ. At the beginning of learning anatomy, I simply thought that the skin is the outermost layer and largest system which covering and protecting from exposure of external elements. The skin acts as a formidable physical barrier, shielding us from external threats, such as pathogens, toxins, and harmful UV radiation. I am more focused on other vital organs, but I underestimate and overlooked how our skin is doing an amazing job performing in immune response for our body. After reading Dr. Gigli's articles how she explored the immune system functions of skin cells, I explored deeper how skin deeply relates to immune response. I have learned that the skin has intricate complexity and multifunctionality in immune response. The skin plays a vital role in our immunological significance, and it functioned in immune defense.
                      The skin defends against infections and toxins. Keratinocytes cells located in the epidermis act as express receptors immune cells that constantly monitor for invaders. When detecting pathogens, it triggers inflammation. Keratinocytes, macrophages, and dendritic cells work together to detect pathogens and maintain tissue balance. According to the Rachel Cotton is a PhD student in the Immunology Program at Harvard stating in her article that “keratinocytes produce some antimicrobial peptides that control resident microorganisms on the skin”.      
                  Macrophages, the versatile immune cells, play a crucial role in maintaining tissue homeostasis and arranging immune responses within the skin. Macrophages are voracious phagocytes, they digest cellular debris, pathogens, and foreign particles. Macrophages are immune conductors, shaping responses across diverse organ systems for examples  phagocytose dead neurons, modulate inflammation, and contribute to brain repair, hepatic macrophages (Kupffer cells) reside in the liver, alveolar macrophages patrol lung airspaces.
                Dendritic cells capture and present antigens. They differ in markers, location, migratory pathways, and immunological function. Dendritic cell can stimulate hundreds to thousands of T cells and interact with other T cells, natural killer cells, neutrophils, and epithelial cells. Rachel Cotton stating in her research summary that “The skin is home to roughly 20 billion T cells .Greater than 95% percent of T cells in the skin have a “memory” phenotype, meaning that these cells have already experienced their cognate antigen, and are poised to rapidly respond to that antigen again”. According to the research finding stating that the skin isn’t just an outer layer; it’s a dynamic interface connecting our sensory experiences to the central nervous system.
             Melanocytes played not only for skin pigmentation, it also actively functioned in innate immunity, which actively mediate immune responses, performed in sensory perception, and synchronize with our inner rhythms. According to Rachel Cotton,PhD student in the Immunology Program at Harvard University, stating in her article that “Langerhans cells are the first immune cell which response to any pathogen that invading the skin”.
              In conclusion, the skin isn’t just a passive covering; it’s a vigilant immune sentinel, tirelessly working to keep us safe. Dr. Gigli’s and Rachel Cotton,PhD Harvard University student’s  research opened my eyes to the skin’s hidden complexities of immune response. Skin-derived immune cells not only modulate local responses but also impact systemic inflammation.When I look at my skin, I see that skin is not just an outer layer but a vital player in our body’s defense—after relating with the research articles; I will explain that the skin played a vital role for our immune system.