Week 8 - Exercise and Immune System Flashcards
Whats the role of the immune system
Govern how the body defends against foreign pathogens including viruses, bactetia and fungi
What are the different ways microbes are shut down
- Trapped by skin cells and mucus
- Killed by antibodies in tears, saliva and mucus
- Removed from the body by shedding skin, coughing, vomiting, diarrhoea or flushing bodily fluids (urine/tears)
What are the 3 innate immune cells
Monocytes
Neutrophils
Natural killer cells
What are monocytes
3-9% of blood
A type of phagoycte (eating cell)
Leave the blood and form macrophages in tissues
Consume microbes and dead cells by phagocytosis
What are neutrophils
60% of blood
Most abundant immune cell in blood (45-75%)
A rapid responder to infection/stress that exits the blood to enter tissues
Engulf microbes (phagocytosis) and kill via the release of toxic molcules (respiratory burst)
What are natural killer cells
1-6% of blood
Destroy virus-infected cells and cancerous cells
Produce proteins, such as cytokines to kill infected transformed cells
Where are complement proteins made
They are made in the liver and circulate as inactive proteins in the blood >30 proteins
What is the role of complement proteins
They can bind to antibodies or patterns on microbes or dead cells. These form complexes that recruit phagocytes to the site via chemical gradients (complement cascade)
What is the role of cytokines
They can be released from innate immune cells to coordinate the immune response and signal to adaptive immune cells
What is the role of dendritic cells
They process parts of a foreign body and present the antigen to cells of the adaptive immune system (T and B cells) in lymph nodes
What are T cells (cell-mediated immunity)
They are a type of lymphocute developed in the thymus (20-40%)
T cells release cytokines that kill virus infected cells or tumours
What are B cells (humoral immunity)
A type of lymphocyte produced in the bone marrow (1-6%)
B cells differentiate into plasma cells and produce antibodies
Antibodies coat infected cell or bacteria or they trigger other immune cells to destroy the cell
What is special about T and B cells
T and B cell responses are specific and have property of memory. This means that when the body re-encounters the same antigen - T and B cells action an immune response based on memory
What are helper T cells
60-70% of T cells
Co-ordinate immune respinse by recruiting other T and B cells to the site of damage/infection
Regulatory t cells have a role in suppressing the activity of the immune system
What are cyotoxic T cells
30-40% of T cells
Highly efficient, specific killers
Recognise antigens on the surface of damaged and/or infected cells or tumours
What are the differnet ways to measure immune function
Self-reported illness
Cellular level
Release of molecules reflecting immune respons
In vivo immunity
How do self-reported illness help measure immune function
Upper respiratory tract infections - number and severity
How does a cellular level help measure immune function
Concentraion of immune cells
Activation/suppression markers on a specific cell type
Measure immune cell function
How does the release of molecules reflecting immune response help measure immune function
Antibodies with anti-microbial properties
Enzymes with a role in phagocytosis
How does in vivo immunity help measure immune function
Antibody responses to a vaccine
Wound healing and/or skin thickening to mild trauma
How does exercise evoke immune responses
Moderate-intensity exercise increases the number of leukocytes in blood
This increase is greater in the minutes after intense exercise followed by a drop below rest in the later hours
This decrease is as a result of a dynamic and complex physiological response
What are the mechanisms that drive immune cell mobilisation
Exercise increases shear stress, sympathetic drive/vasoconstriction and adrenaline concentrations that demarginate immune cells into peripheral blood
This response is not uniform, with effector immune cells being preferentially mobilised
Whats the effect of cells mobilising into the blood during exercise
The cells mobilised into the blood during exercise have high function and tissue homing potential. These cells therefore have the highest capacity to leave the circulation
Whats the effect of exercise induced muscle tissue injury
This injury elicits a strong innate immune response involving neutrophils, monocytes and macrophages
What are the processes that proteins iniate, mediate and termiante muscle repair?
- Movement of immune cells into muscle (mitigation)
- Muscle fibre breakdown and regeneration
- Anti-microbial defence
What are the acute improvements in immunity adaptations
Decreased:
Number of infections
Severity of infctions
Increased:
Antibody production
Response to vaccination
Wound healing
Surveillance of cancer cells
What are the chronic improvements in Immunity Adaptations
Decreased weight loos (adipose tissue) thus decreased inflammation
Improved vasculature health and thus immune cell recirculation
Increased anti-inflammatory blood profile
How does exercise effect the natural decline in immunity
Regular physical activity/ reduced sedentary
time can offset the natural decline in
immunity with age
How can exercise effect people with immune illness
Regular exercise may also improve immunity
in people with autoimmune, cardiovascular,
neurological and metabolic illness
Whats the effect of moderate amounts of exercise on immune function
moderate amounts of exercise
enhance immune function
What does some research suggest about the effect of intense exercise on immune function
periods of intensified
training can impair immune function
