The Immune System...

The immune system is a system our bodies go through every time pathogens (biological agents that causes disease like bacteria, fungi, protists, and even “viruses”- even though they are not living) try to enter our bodies. What makes this system work properly are the T-cells which has the function of determining what belongs to our bodies and what doesn’t, (or else cells would kill parts of our own bodies).

When we get sick we usually go to a doctor and if he determined we have some kind of infection we start taking antibiotics to stop and cure the infection. The problem is that antibiotics don’t always work since they are only effective and able to do their work (which is to block metabolic ways or prokaryotic cell- cell wall) on bacteria or living things that contain a cell. Since viruses are non-living, with no cell or even a metabolism, antibiotics cannot perform their job and therefore are not effective. This is where our immune system becomes essential in our bodies. It not only prevents infections from bacteria or anything that an antibiotic is able to function on, but is also able to stop viruses and cure our bodies from diseases it causes.

Watching the videos Ms. Silva posted on the blog this week about how our immune system combats diseases and antigens that enter our body, (http://outreach.mcb.harvard.edu/animations_S04.htm) I was able to understand this process a little better. Firstly I learned that our bodies contains and produces many things to avoid antigens from entering our bodies. The “first line of defense” in our bodies is our skin. It has two layers: the epidermis (superficial) and the dermis (with capillaries). We also have mucus membranes in our respiratory tract that produces mucus that trap and kill microbes. The lysosomes present in mucus, tears, saliva, and even breast milk are also anti-bacterial, with the cilium that sweeps back the mucus to our throats, making all the germs go to the stomach where they are killed by the acid.

Our “second line of defense”, shown through the videos, are inside our bodies and organisms. We have phagocytosis which is the ingestion and digestion of all the “bad” substances. This happens through the phagocytic leucocytes, also known as Macrophages, which are large white blood cells that engulf the pathogen and digests it. They then release signals “calling” the T-cells, after digesting the antigens and leaving pieces of it in itself, which are the main and most important cells in the process of the immune system to help them. As I saw on the video the T-cells are the one that determine what is bacteria, viruses or any pathogens that don’t belong to our bodies. Once they are recognized T-cells activate specific B-cells (which are the ones that make antibodies) which then divide and form plasma cells, which secretes the antibody necessary to kill the antigen. We also produce memory cell, which stay in circulation and prepared our body if the same antigen enters again, leaving the body prepared for it with a fester “counter attack”.

I also learned from the videos and our notes that what really causes HIV is the non-function of the T-cells, which as I mentioned before, is one of the most important things to actually make the whole immune system work. The HIV damages the helper T-cells, which loses its ability to identify the pathogens and therefore create the antibodies necessary to kill it. It seems pretty simple, to find some solution to it, but it clearly isn’t, keeping in mind the social implications having HIV brings like prejudice, difficulty in finding a job, education, and the negative aspects of AIDS.

With all of this I was able to conclude that the immune system is definitely essential to our lives and health, since our world and day-to-day lives are literally full of bacteria, viruses, and all kinds of pathogens that we remain constantly exposed to.