The classical complement pathway differs from the alternative pathway in that it requires a trigger in the form of an antigen-Ab complex. Only two antibodies can fix complement—IgG and IgM. The classical pathway is shown in Figure 5.3. The small fragments that are cleaved from the proenzymes have activities such as chemotactic stimulation and anaphylaxis. The bar over the names of some components of the pathway denotes an active complex. Note that the classical pathway does not operate with C1 to C9 in sequence. Rather, the sequence is C1, C4, C2, C3, C5, C6, C7, C8, and C9.
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With all the stresses and strains of modern living, panic attacks are become a common problem for many people. Panic attacks occur when the pressure we are living under starts to creep up and overwhelm us. Often it's a result of running on the treadmill of life and forgetting to watch the signs and symptoms of the effects of excessive stress on our bodies. Thankfully panic attacks are very treatable. Often it is just a matter of learning to recognize the symptoms and learn simple but effective techniques that help you release yourself from the crippling effects a panic attack can bring.