Overview of the immune system Flashcards
What is the immune system?
Immune system is body’s ability to resist or eliminate potentially harmful foreign materials (pathogens)
What is the meaning of immunity?
Protection from infectious diseases
What is a pathogen?
Any microorganism that causes harm
What are the two main branches of immunity?
Innate
Acquired
What is acquired immunity?
Production of antibodies.
Retain memory of pathogen invasion.
What is innate immunity?
Ability to take action as soon as pathogen will infect us.
What are some external barriers?
skin
mucus
flushing action
Epithelial cells of nasal passages and bronchi
Stomach
sweat
tears/salivia
Differences between innate and adaptive immunity?
Innate- always present (ready to attack);
many pathogenic microbes have evolved to resist innate immunity
Adaptive- stimulated by exposure to microbe; more potent
What are examples of components of innate?
phagocytes, complement and NK cells /natural killer cells
Examples of components of adaptive immunity?
include mainly antibodies that are produced by B lymphocytes, and Cytotoxic cells that are differentiated from T cells
Difference in response of innate immune response and adaptive immune response?
Innate:
Non-specific
Distinguishes between human cells and pathogens, but not between different types of pathogen
Fast and immediate: first to come into play
No memory: will produce the same response
Adaptive:
Highly specific
Distinguishes between different pathogens based on shapes on the surface – called antigens
Slower: Can take few days to develop
Immunological memory: memory cells remember
What branches can we divide innate immunity into?
Cellular - Phagocytes, Eosinophils, mast cells and basophils
humoral - complement and cytokines
What are phagocytes?
Phago: eating
Cyte = cell
are the cells of the immune system that track down, engulf and destroy bacteria, other pathogens as well as own damaged or dead cells.
Describe characteristics of neutrophils?
Most abundant White Blood Cells (WBCs) (8x106/ml~50-60%)
Track down, engulf and destroy pathogens,
They contain granules that are filled with many destructive enzymes such peroxidases, alkaline and acid phosphates which are responsible for kill and destroy bacteria and other pathogens
Describe characteristics of macrophages?
~5% of WBCs, larger than neutrophils
Can engulf much more
Macrophages (big eaters)
Break down pathogens, process specific components of these pathogens called antigens and present these processed antigens to the cells of the adaptive immunity to produce specific immune response in the form of Ab and cytotoxic T cells
Antigen Presenting Cells (APCs)
