When a pathogen enters the body, it first encounters the body's physical and chemical barriers, primarily the skin and mucous membranes. These barriers provide a first line of defense by preventing the pathogen from entering deeper tissues. If the pathogen breaches these surfaces, it then encounters immune cells and proteins in the innate immune system, which act quickly to identify and combat the invader.
reproduce. The more there is the more likely they are to survive x
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Once the body activated, killer T cells it recognize pathogen and destroy them. In response that will create memory B cells and T cells specific to a certain pathogen, so if it ever came back it will be killed immediately.
It is called a pathogen! it carries the bacteria fugus disease or whatever else into the body!
The TB pathogen enters the body through inhalation of airborne droplets containing the bacteria. These droplets are released when an infected person coughs, sneezes, or speaks. Once inhaled, the bacteria can travel into the lungs and cause infection.
Yes, contagious diseases are infections. Infections are occur when a pathogen (germ) enters the body and reproduces.
A very broad answer to a very broad question... A "pathogen" as defined by a dictionary would be, "any disease-producing agent, esp. a virus, bacterium, or other microorganism." First- a "pathogen" in drinking water will cause nothing unless someone or something drinks the water or if the "pathogen" enters the body/host by some other means... Second- even once the "pathogen" enters the body it may still cause nothing, as the quantity of the "pathogen" must be sufficient to cause the would be disease... Third- because a "pathogen" could be any one of millions of things, what disease would be caused by your hypothetical "pathogen in the drinking water" would depend entirely on what it is... You should seriously consider being more specific about your question. If you are interested in a specific pathogen and the associated disease, please try again.
ADAPTIVE immunity. Your body sees the pathogen, so it can be ready if it ever encounters it again.
Respiratory tract
The purpose of a vaccine is to expose an otherwise naive immune system to the pathogen, so it can recognise and quickly respond to that pathogen if it encounters it again. If you've already had the disease, your body will already recognise it if it sees it again.
The pathogen tries to infect the body. The defense mechanism of the body resists the entry of the pathogen. If pathogen succeeds the infection is established and the body becomes sick.