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describe the sructure and the function of the immune system
everything to know about the immune system
everything to know about the immune system
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The immune system is a highly evolved and complex defence system, armed against millions of potential pathogens that may cause infection at any point. Pattern recognition receptors, known as PRRs, are displayed by the cells of the innate immune system, such as macrophages and dendritic cells, and recognise pathogen associated molecular patterns or PAMPs. PAMPs are evolutionary conserved structural similarities found in many pathogens but not in the host’s own cells allowing the innate immune system to distinguish between self and non self and to react to the pathogens immediately (Mogensen, 2009). Antigen recognition receptors are used by the lymphocytes of the adaptive immune system to provide a highly specific and targeted response to a precise epitope of an antigen. However as a single lymphocyte carries only a single type of antigen recognition receptor that recognises one type of antigen the chance of a pathogen of finding a lymphocyte with a given specificity is low. Therefore the adaptive immune response takes time to mobilise hence the innate immune system is essential to keep the infection …show more content…
The less specific nature of PRRs is crucial to the immediate role of the innate immune system allowing them to respond to a wide range of pathogens. In line with their role innate immune cells are found dispersed throughout the body (Mogensen, 2009). In contrast T and B cells will congregate in the lymph nodes until they are activated. As I previously mentioned finding a T or B cell with a specific antigen binding capability is rare so therefore once a precise lymphocyte has been activated by an antigen, it must undergo clonal expansion to ensure there is sufficient amount of that specific cell to neutralise the pathogen and this process takes a few days. Therefore numbers and effectiveness of specific TCRs and BCRs fluctuate with time (Kindt, et al.,
The B cells, T cells, Macrophage, and Antibodies are all a very large part of the immune system. There are two types of T cells, killer and helper T cells. Killer T cells find and destroy cells infected with bacteria, and helper T cells control the activity of other cells in the immune system. Then, B cells are considered the “clean up crew,” attacking any bacteria or viruses the T cell left behind. They also make antibodies, which are essential for trapping invading viruses and
“Cells Involved In Immune Responses and Antigen Recognition.” Microbiology and Immunology. Web. 18 Dec. 2011. .
When a familiar antigen is encountered, B-lymphocyte memory cells will divide and form new antibody-producing plasma cells. Some memory cells will be left, however, so that the body can respond to any number of future infections with the same pathogen. The second time the immune system encounters a pathogen for a second time, antibodies are produced more rapidly and their effect lasts longer. Memory B cells have an affinity for a particular antigen as well. Also, larger amounts of antibodies are produced in the secondary response resulting in a stronger response.
1. EQ: How does the structure and function of my immune system keep me healthy?
The innate immune system is given to you at birth and always has microbes ready to fight (Joanne M. Willey, 2014). This system is very fast to detect and attempt to eliminate any invading cells. It reacts by triggering Toll-like receptors (TLRs) who then fasten to pathogen-associated molecular patterns (PAMPs) (Joanne M. Willey, 2014). The first line of defense in the innate immune system contains the skin and mucous membranes, along with normal microbiota (Joanne M. Willey, 2014). The second line of defense of the “early-warning” system consists of natural killer cells, phagocytes, eosinophils, dendritic cells, macrophages, inflammation, fever, and antimicrobial substances (Joanne M. Willey, 2014). Although a powerful system, it cannot take
T cells are used to find infected cells that are tagged with a specific antigen. Once the antigen is in contact, the T cells will destroy the cell; this results in cell mediated immunity. (ahn pg 740)
The b cell is the helper cell it will contact the T cell and can locate a foreign substance, create antibodies to kill it, and also will remember the specific pathogen or antigen forever in case your body ever has to fight it again.
The macrophages engulf and digest the foreign pathogens and leave behind parts of the pathogen called antigens that stimulates the immune system to attack them. The T-lymphocytes are a type of white blood cell that can recognize antigens that are not part of the human body (non-self) and attack the human cells that have been invaded by the pathogen associated with this non-self antigen. B-lymphocytes, another type of white blood cell, also recognize foreign antigens and produce antibodies that attack and neutralize the foreign antigens to fight the infection. When a new pathogen is first detected by the immune system, it can take up to several days for the immune system to properly coordinate all the different immune cells required to fight the infection (Understanding How Vaccines Work, 2013). However, once the infection has been eliminated, the immune system has the ability to remember all of the foreign antigens that have entered the body. The memory T-lymphocytes and memory B-lymphocytes will remember every antigen they have ever encountered throughout the human’s lifetime and are able to quickly respond and initiate the immune response if the same antigen is detected again. The immune system keeps a huge supply of “millions and possibly billions of different antibodies on hand to be prepared for any foreign invader by constantly creating millions of new B cells” (How Do Vaccines Work?, 2011). This process of antigen memory and antibody production is also called acquired immunity, and it the basis to understand how vaccines
This immunity is dependent upon our body to be exposed to a particular type of pathogen once before. After the exposure, our body’s immune system learns of a way to counteract the foreign substance. The immune system learns the most effective way to counter each antigen that enters and then retains that strategy until the same pathogen attacks on it again. It completely customizes its attack, adapts to new conditions and remembers the information. This why people are given shots of inactivated viruses. When these viruses enter the blood stream, the body thinks that they are harmful pathogens and then develops a way of counteracting to them. After battling these viruses, they remember their form of attack, so in case these same harmful viruses enter the blood stream again, they can deal with them quickly and efficiently. Lymphocytes (T and B cells are required for this immunity). The antibodies IgA are expressed in our body on the mucous surface of the gut. When foreign substances enter, the intestine, they kill those pathogens before they can even grow in the
ANS: Specific immunity is when the body produces antibodies to react to an antigen. Non-specific immunity is the body's first reaction to a foreign antigen.
There are 2 levels presented in generating the immunological tolerance: central tolerance (upper level) and peripheral tolerance (lower level). Central tolerance can be developed during fetal development, occurring in central lymphoid organs such as thymus and bone marrow. In order to back up the process, peripheral tolerance develops after childbirth. In the upper level, the nascent lymphocytes that have antigen receptors are being encoded in the randomly rearranged genes, and also being exposed to the antigenic signals from self-molecules. The positive selection stimulates weak interaction with low-affinity signals. This means to select only suitable lymphocytes for the immune repertoires. On the other hand, the negative selection requires apoptosis (cell-death) to eliminate self-reactive lymphocytes caused by the strong
Before we proceed further lets first understand what this immunity system is- According to Wikipedia "In
Adaptive immune system happens much quicker to the presence of an “infection creating potent mechanisms for neutralizing or eliminating the microbes. There are two types of adaptive immune responses: humeral immunity, mediated by antibodies produced by B lymphocytes, and cell-mediated immunity, mediated by T lymphocytes.”
The first line of defense used in the immune system is physical barriers. The first physical barrier is the skin. The skin has sebum (oil) which is on the skin’s surface making it acidic and making many pathogens unable to grow on it. Sweat also contains special enzymes to attack bacteria, killing it, and making it unable to spread. The second physical barrier is Mucus Membranes which covers majority of internal body structures making it hard for pathogens to affect these systems. It also produces a thick fluid called mucus that traps pathogens before they start in infect. The second line of defense is when pathogens make it past the physical barriers causing your
In addition to serving as a drainage system, the lymphatic system, along with the lymphoid tissues and organs, play a vital role in the body’s immune system to create an immune response. The body ...