Week 8 - Exercise and Immune System

Question 1

Whats the role of the immune system

Answer 1

Govern how the body defends against foreign pathogens including viruses, bactetia and fungi

Question 2

What are the different ways microbes are shut down

Answer 2

1. Trapped by skin cells and mucus
2. Killed by antibodies in tears, saliva and mucus
3. Removed from the body by shedding skin, coughing, vomiting, diarrhoea or flushing bodily fluids (urine/tears)

Question 3

What are the 3 innate immune cells

Answer 3

Monocytes
Neutrophils
Natural killer cells

Question 4

What are monocytes

Answer 4

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

Question 5

What are neutrophils

Answer 5

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)

Question 6

What are natural killer cells

Answer 6

1-6% of blood
Destroy virus-infected cells and cancerous cells
Produce proteins, such as cytokines to kill infected transformed cells

Question 7

Where are complement proteins made

Answer 7

They are made in the liver and circulate as inactive proteins in the blood >30 proteins

Question 8

What is the role of complement proteins

Answer 8

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)

Question 9

What is the role of cytokines

Answer 9

They can be released from innate immune cells to coordinate the immune response and signal to adaptive immune cells

Question 10

What is the role of dendritic cells

Answer 10

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

Question 11

What are T cells (cell-mediated immunity)

Answer 11

They are a type of lymphocute developed in the thymus (20-40%)
T cells release cytokines that kill virus infected cells or tumours

Question 12

What are B cells (humoral immunity)

Answer 12

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

Question 13

What is special about T and B cells

Answer 13

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

Question 14

What are helper T cells

Answer 14

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

Question 15

What are cyotoxic T cells

Answer 15

30-40% of T cells
Highly efficient, specific killers
Recognise antigens on the surface of damaged and/or infected cells or tumours

Question 16

What are the differnet ways to measure immune function

Answer 16

Self-reported illness
Cellular level
Release of molecules reflecting immune respons
In vivo immunity

Question 17

How do self-reported illness help measure immune function

Answer 17

Upper respiratory tract infections - number and severity

Question 18

How does a cellular level help measure immune function

Answer 18

Concentraion of immune cells
Activation/suppression markers on a specific cell type
Measure immune cell function

Question 19

How does the release of molecules reflecting immune response help measure immune function

Answer 19

Antibodies with anti-microbial properties
Enzymes with a role in phagocytosis

Question 20

How does in vivo immunity help measure immune function

Answer 20

Antibody responses to a vaccine
Wound healing and/or skin thickening to mild trauma

Question 21

How does exercise evoke immune responses

Answer 21

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

Question 22

What are the mechanisms that drive immune cell mobilisation

Answer 22

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

Question 23

Whats the effect of cells mobilising into the blood during exercise

Answer 23

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

Question 24

Whats the effect of exercise induced muscle tissue injury

Answer 24

This injury elicits a strong innate immune response involving neutrophils, monocytes and macrophages

Question 25

What are the processes that proteins iniate, mediate and termiante muscle repair?

Answer 25

1. Movement of immune cells into muscle (mitigation) 2. Muscle fibre breakdown and regeneration 3. Anti-microbial defence

Question 26

What are the acute improvements in immunity adaptations

Answer 26

Decreased: Number of infections Severity of infctions Increased: Antibody production Response to vaccination Wound healing Surveillance of cancer cells

Question 27

What are the chronic improvements in Immunity Adaptations

Answer 27

Decreased weight loos (adipose tissue) thus decreased inflammation Improved vasculature health and thus immune cell recirculation Increased anti-inflammatory blood profile

Question 28

How does exercise effect the natural decline in immunity

Answer 28

Regular physical activity/ reduced sedentary time can offset the natural decline in immunity with age

Question 29

How can exercise effect people with immune illness

Answer 29

Regular exercise may also improve immunity in people with autoimmune, cardiovascular, neurological and metabolic illness

Question 29

Whats the effect of moderate amounts of exercise on immune function

Answer 29

moderate amounts of exercise enhance immune function

Question 30

What does some research suggest about the effect of intense exercise on immune function

Answer 30

periods of intensified training can impair immune function