immune system Flashcards
2 branches of the immune system
Innate (non-specific)
Adaptive (specific).
what is the immune systems primary role
body defends against foreign pathogens including viruses (cold, flu), bacteria (pneumonia) & fungi, by recognising the difference between self and nonself
cells of the innate immune branch
- Monocytes/ Macrophages - 0.2-1.0 x 10(9) /l
- Neutrophils - 2.5-8 x 10(9) /l
- Natural Killer Cells - 0.1-0.3 x 10(9) /l
cells of the adaptive immune branch
- Lymphocytes (T-cells and B-cells) - 1.5-3 x 10(9) /l
cells of the adaptive and innate immune system
- White blood cells (or leukocytes) - 5-10 x 10 to the power of 9 /l
physical barriers
- what are they
- examples
- physically prevent substances from infecting
- eg. hair, mucus, skin, saliva, coughing, vomit, urine, tears, diarrhoea
2 types of innate immunity
cell-mediated and humoral
what is innate cell-mediated immunity
recognises pathogens non specifically
what is a monocyte
- type of phagocyte that engulfs microbes and dead cells by phagocytosis
what is a neutrophil
- type of phagocyte that engulfs microbes and dead cells by phagocytosis and also kills via the release of toxic molecules (respiratory burst)
what is a natural killer cell
- Enters and Destroys virus-infected & cancerous cells by producing proteins to kill the host cell
what is innate humoral immunity and how does it work (compliment proteins)
- Certain complement proteins can bind to antibodies or patterns on microbes (e.g., bacteria) or dead cells. They label and recruit phagocytes to the site via chemical gradients (complement cascade).
what cells bridge innate and adaptive immunity and how
- dendritic cells/antigen presenting cells process parts of foreign bodies and present the antigen to cells of the adaptive immune system (T and B cells) in lymph nodes.
what is adaptive immunity
- When the body re-encounters the same antigen – T and B cells action an immune response based on memory
adaptive cell mediated immunity
- what cells
- helper t cells activate b cells to divide into antibodies and stimulate cytoxic t cells
- cytoxic t cells reognise antigens on cells and release toxins and cytokines that result in host cell death
what cells are used in adaptive humoral immunity and what do they do
- b cells divide into plasma cells which produce antibodies which bind to and recruit phagocytes to destroy infected cells
how can we measure immune function
- ask about how often someone has been ill
- concentration of immune cells
- measure antibody/enzyme responses to infection
- speed of recovery from a cut
what is the open window for infection hypothesis
- increase in immune cells seen during exercise, then a drop below rest in hours after
- theory is that in this period you are vulnerable to infection
why the open window for infection hypothesis is wrong
- cells are mobilised from endothelial wall which show an increase but not really
- immune cells are redistributed to sites of damage/infection where they are needed, eg. muscles
how do t cells use metabolism to provide ATP to move and produce molecules to destroy infected cells
use glycolysis
theory why individuals become susceptible to illness post exercise
- immune cell activation is impaired as oxygen and nutrient demands cannot be met so cannot initiate an appropriate immune response
how long after exercise do immune cells migrate to tissues to address damage
- benefits of this migration
- 2 hours
- reduce inflammation, faster wound healing, faster muscle healing, reduced number of infections at the site
what is better for immune function (as we currently know), moderate or heavy-intensity exercise
- Moderate - More antibodies and immune cells, reduced inflammation, better function of immune cells and vaccine response
- Heavy- Less antibodies and responsive immune cells, reduced immune cells and function of immune cells, poorer redistribution of immune cells
impact of exercise on older and clinical populations’ immunity
- can improve and delay the decline in immune function
- may inhibit tumour growth
