sensitization...

sensitization is a term used in medicine to describe the first encounter of a body with an antigen. sensitization is the first step of an allergic reaction. the result of the meeting of body with antigen causes the production of antibody, which, during the next encounter with the antigens, will combine with it, forming immune complex (antigen-antibody complex) ......this complex will react within susceptible person with high sensitivity, and thus causing  activation of cascade of immune reaction, manisfested by skin lesions, bronchial asthma....etc...

if the immune reaction is not suppressed, the "chemistry" will become more brightly manifested each time the body encounters with the antigens....

the same principle could be applied to the academical lectures here, which might seem redundant to most of the people here. i get it that it's boring to go to lecture for some. and i'm not here to insult those who does not go lecture.....so don take it personally...

attending lectures can be taken as a form of "sensitization". while u might come out of the lecture hall thinking that u have 0 input, try to think of it as it's the initial encounter with the "antigen" ie the materials which u have to put in your brains...and it's no wonder that no chemistry is seen......but trust me....the "antibody" is being produced inside your body......and the "immune memory" will remain in your body for sufficient amount of time....

all you need is 2nd, 3rd, 4th encounter with the lecture materials to have a sufficient manifestation of "allergic reaction". the more u expose yourself to the "antigens" the bright manifestation will be...well, if your immune response doesn't react well to that particular antigen....you just have to continue with 5th, 6th and 7th.....and so on....

nevertheless, "sensitization" is very important....(altho i believe many would beg to differ)

of course, many attempted to get "sensitization" for once or twice....but quickly gave up due to the lack of effect...they wanna see instant reaction, which is quite impossible ...coz as i've said just now, the first encounter doesn't produce much manifestation, but it's an important step to the following reaction....

if you get enough "sensitization", you will understand how easy it is to develope the chemistry during your exams later.....( well, not VERY easy, but relatively easier....) coz ur immune complex react faster with each "sensitization".....thus it's easier to build up the antibodies earlier in your body than to have to sensitize it many times in s short time, sometimes so short that your immune system can't handle it, and thus leading to severe "anaphylactic shock"....

and then there's this remark on why should we go lecture, when we can get the senior's notes without any effort....why waste our time attending lectures?

ok, let me tell you about the active and passive immunity. active immunity is when you are injected small amount of deactivated antigen into your body and it actively produces antibody to prepare for the subsequent meeting of the antigens....while passive immunity refers to the antibody which is produced by other animals which were injected certain antigens. those antibodies are named serum and are transferred into the human body. it is called "passive" because our body does not actively produce any antibody, and thus, do not have the "memory" on how the antigen works....

see, when a person with active immunity meets an antigen, he fights it with his own antibody....while a person injected with passive immnunity fights it with antibody produced by a horse! of course, u could expect that the effect of a person with an active  immunity would resist the antigen longer....while the passive ones will need to depend on another dose of serum antibody....

after the war with the antigen is over, the person with active immunity will have residual memory of the antigen, while there is no trace of memory in those will passive immunity...

now try to apply it with the lecture as an antigen and senior's note as a horse's serum.....(no disrespect to the seniors watsoever)....the math is simple....while it's easy not to give any effort to produce any "antibody", reading second hand materials tend to give less input and effect on the "immune memory"......compared to the impact given exposing yourself to the "real deal".....