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The adaptive immune response is the body's second line of defense. The cells of the adaptive immune system are extremely specific because during early developmental stages the B and T cells develop antigen receptors that are specific to only certain antigens. This is extremely important for B and T cell activation.
In the first line of defense, inhaled bacteria are trapped by mucus and are swept toward the pharynx and are swallowed. [1] Bacteria which penetrate the mucous layer are dealt with a second line of defense which includes antimicrobial peptides that are secreted by the surface epithelium of the respiratory tract which kill many strains of ...
The first is that the fetus occupies a portion of the body protected by a non-immunological barrier, the uterus, which the immune system does not routinely patrol. [3] The second is that the fetus itself may promote local immunosuppression in the mother, perhaps by a process of active nutrient depletion. [3]
The mucosal immune system consists of a cellular component, humoral immunity, and defense mechanisms that prevent the invasion of microorganisms and harmful foreign substances into the body. These defense mechanisms can be divided into physical barriers (epithelial lining, mucus, cilia function, intestinal peristalsis, etc.) and chemical ...
A scanning electron microscope image of a single neutrophil (yellow/right), engulfing anthrax bacteria (orange/left) – scale bar is 5 μm (false color). The immune system is a network of biological systems that protects an organism from diseases.
Humoral immunity is the aspect of immunity that is mediated by macromolecules – including secreted antibodies, complement proteins, and certain antimicrobial peptides – located in extracellular fluids.
The innate immune system is an alternate defense strategy and is the dominant immune system response found in plants, fungi, prokaryotes, and invertebrates (see Beyond vertebrates). [ 2 ] The major functions of the innate immune system are to:
The second and third lines of defense operate by making changes to the buffers, each of which consists of two components: a weak acid and its conjugate base. [ 5 ] [ 13 ] It is the ratio concentration of the weak acid to its conjugate base that determines the pH of the solution. [ 14 ]