Innate Immunity - are circulating precursors to macrophages...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Innate Immunity If pathogens do gain entry into the body, the body's innate defenses come into play. Neutrophils are multi-talented defenders that destroy invading bacteria by phagocytosis and creating a killing zone. Phagocytosis is relatively slow as neutrophils can only destroy a few bacteria at a time. The respiratory burst creates a toxic environment (a killing zone) in the vicinity and may destroy multiple bacteria at one time. The production of O 2 .- , HClO , and H 2 O 2 by neutrophils destroys nearby cells, including bacteria. Eosinophils are also phagocytes, but they phagocytose antigen- antibody complexes and allergens rather than invading microorganisms. Eosinophils also create killing zones around parasites by releasing digestive and toxic enzymes. Basophils aid the mobility of other WBCs by secreting histamine and heparin . These chemicals result in increased blood flow to the site of infection and aid the movement of WBCs out of the circulatory system and into the tissues. Monocytes
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: are circulating precursors to macrophages, which leave the circulatory system and colonize lymph nodes and other tissues. The final type of cell involved in innate immunity are the natural killer cells. Natural killer cells are a sub-class of T-lymphocytes that lyse cancerous host cells or host cells infected with viruses or bacteria by release of perforin proteins. (See Figure 3) Figure 3 Complement System and Inflammation The complement system is a group of blood plasma proteins that are activated by pathogenic invasion. When activated, these proteins either bind to pathogens or antibody-pathogen complexes to target them for destruction by phagocytosis or form a membrane attack complex to lyse the invading cell. (See Figure 4) Figure 4 Inflammation, while painful, is a defensive response to tissue injury that limits the spread of pathogens, removes cellular debris, destroys pathogens, and facilitates tissue repair....
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern