When someone is exposed to poison ivy, the effects are not i…

When someone is exposed to poison ivy, the effects are not immediate. The characteristic rash, redness, and swelling appear up to days after exposure. (a) Why does poison ivy exposure elicit a delayed hypersensitivity response? (b) Contrast Type I and Type IV hypersensitivity reactions. (Your answer should describe differences between these types of reactions)

The human immune system defends against a wide variety of pa…

The human immune system defends against a wide variety of pathogens. Unicellular pathogens can be classified as intracellular or extracellular, and the immune system must target these two types of pathogens differently. (a) Contrast intracellular and extracellular infections and the pathogens that cause them. Describe key differences. (b) Contrast the innate immune system response to intracellular and extracellular infections and the pathogens that cause them. Describe key differences.