Quiz-
Intro: first of all, the immune system is what protects us from infections. The immune system has two major branches: Innate (non-specific) and adaptive (specific).
Question 1.)
The elements for this part of the immune system are anatomical barriers, secretory molecules, and cellular components. This response only recognizes an antigen but not what type of antigen it is. Our barriers are our skin and internal epithelial layers, movement of intestine, and Broncho-Pulmonary cilia . Our skin has a very low ph making it hard for bacteria to live there. It also has other bacteria (normal flora) and chemicals that can push "invaders" out of the way. Stomach acid also acts as a "fighter of invaders" because of its high ph scale.
If the invader gets through our skin (a cut or scratch) then we have a response called inflammation. When the infection swells, heat is increases and we send in macrophage. The phagocyte will engulf the antigen and the lysosomes inside the macrophage will dissolve the antigen. Some parts of the antigen will form an major histocompatibility complex (MHC) type two. This will then be presented on the outer membrane of the phagocyte. This will help with the specific response of our immune system.
A phagocyte can determine which cells are antigens by the cell's receptors. The most common phagocyte is the neutrophils, which are known for being fast and abundant. others phagocytes are macrophages and dendritic cells.
Question 2.)
There are two types of lymphocyte called A and T. B lymphocytes are made in the bone marrow and they are in charge of the humoral response. a humoral response is defined by the response that happens in the fluid of your body. B lymphocytes produce antibodies specific for that antigen. It also produces memory B cells so that our body will have that type of immunity for that specific antigen for the rest of our lives.
T lymphocytes are in the thymus and are in charge of a cell-mediated response to antigens. This means that the response attacks already infected cells. T lymphocytes create "killer" cells that target infected cells create surface contact. After that, the cell releases target - oriented granules into the other cell. Then the cell will be broken down.
Both of these responses are controlled by the helper T cells. The helper T cells us the shape of the antigen given to them by MHC2 (I mentioned it earlier). It then passes on this information to the B cells. The helper T cells also then activate the killer T cells. Without the helper T cells, our immune system would be in trouble. That's why HIV is so deadly because the helper T cells are infected by the virus.
Question 3.)
This question connects easily with the concepts I just talked about. Both the T and the B lymphocytes create what are called memory cells besides the antibodies and the killer T cell. The memory cell is in charge of memorizing the receptor shape of a specific antigen.
The picture above shows how the memory T cell passes on information about the antigen to the B cell. The B cell is now "equipped" with the right "tools" so it can attack the virus again and have it be more effective. To reiterate what I said in the previously answered questions, the T helper cell initially gets it information from the MHC2. This is the result of the phagocyte digesting the antigen, and then forming a peptide bond with one of the antigens proteins. This newly formed protein is then placed on the cell membrane where other "defender" cells like the T helper cell can get the information needed to make antibodies specifically for that antigen.
The image above shows the transferring of information from the phagocyte to the T cell. It well then keep this information if the same antigen shows up in the body system. Connecting this to the flu, this is why people get the flu each year. The flu is constantly changing due to mutations in its DNA. This is why its so hard for doctors to find an immediate cure. Also, the flu shot is just a predication of what the flu will look like this year.
Question 4.)
So we know the immune system attacks antigens or invaders in our body ,but how do our cells know the difference? This takes us back to the concept of B cells and T cells. Both of these types of cells have receptors that are created at random. This means that a B cell could create an antibody for a protein needed to survive such as insulin. One way our body prevents this from happening is by placing insulin of another bodily protein in the environment where that B cell or T cell is being made. If any of the "attacker" cells being made in the bone marrow or thymus have a receptor that matches a vital protein, it will be destroyed before it has a chance to enter the blood stream.
However, once the B cells and T cells enter the blood stream, the can now destroy antigens that enter the system without the worry of being destroyed. T cells and B cells use their cell receptors as communication from the antigen back to their own cell and respond accordingly.
However, this process isn't perfect. If a mutation occurs, then your body might start attack your own cells. The result is then called an Auto-Immune Diseases.
Works Used:
