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Unit 4 – Immunology and Public Health Immune system
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Unit 4 – Immunology and Public Health Immune system.

Jan 06, 2018

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Immunity is the ability of the body to –resist infection by a pathogen –or to destroy the pathogen if it invades the body The body has an immune system for defence against – pathogens, –some toxins produced by living things –cancer cells Non-specific Cellular Defence
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Page 1: Unit 4 – Immunology and Public Health Immune system.

Unit 4 – Immunology and Public Health

Immune system

Page 2: Unit 4 – Immunology and Public Health Immune system.

Learning Intention:

To learn about the immune system and non-specific cellular defences

Success Criteria:

By the end of the lesson I should be able to

• Give examples of physical (e.g epithelial cells) and chemical (e.g secretions, stomach acid) defences against infection.

• Describe the inflammatory response to include release of histamine by mast cells, causing - vasodilation

- Increased capillary permeability• State that this response results in increased blood flow.• State that the resulting secretion of cytokines leads to an accumulation of phagocytes

and the delivery of anti-microbial proteins and clotting elements.• Describe the function of phagocytes to include the release of cytokines, stimulation of

the specific immune response and recognition of surface antigens, leading to phagocytosis.

• Describe the process of apoptosis by NK cells to include the release of cytokines, stimulation of the specific immune response and the induction of viral infected cells to produce self-destructive enzymes.

Page 3: Unit 4 – Immunology and Public Health Immune system.

• Immunity is the ability of the body to – resist infection by a pathogen – or to destroy the pathogen if it invades the body

• The body has an immune system for defence against– pathogens, – some toxins produced by living things– cancer cells

Non-specific Cellular Defence

Page 4: Unit 4 – Immunology and Public Health Immune system.

Epithelial cells

Epithelial cells are our first line of defence against infection.

They line the surfaces and cavities of the entire body.

Form a physical barrier against infection.

Page 5: Unit 4 – Immunology and Public Health Immune system.

These cells cover almost the entire surface of the body.

They grow constantly upwards and outwards from the bottom layer and by around 14 days they have become dead cells called stratum corneum which flake off taking any bacteria or pathogens with them.

Epithelial cells also produce secretions such as enzymes, hormones and lubricating fluids that can defend against infection.

Page 6: Unit 4 – Immunology and Public Health Immune system.

SecretionsOn all the inside surfaces of the body that can be exposed to bacteria and pathogens a substance called mucus traps dirt and germs, preventing them from entering the blood. Various glands produce antimicrobial secretions that help kill microbes.

Page 7: Unit 4 – Immunology and Public Health Immune system.

Other defences

• Tiny hairs at the entrance to the nose.

• Cough and sneeze reflexes.

• ‘Friendly’ bacteria.

Page 8: Unit 4 – Immunology and Public Health Immune system.

Think – pair - share

• Under what circumstances might this first line of defence fail?

• What might happen if bacteria manage to cross the barrier?

• As a class try to come up with as many answers as possible

Page 9: Unit 4 – Immunology and Public Health Immune system.

Ideas

• (may include cuts to the skin – breaking the barrier, use of antibiotics – killing off ‘helpful’ bacteria, over-cleanliness, immune-compromised individuals etc). If bacteria cross the barrier this could lead to infection and further immune responses.

Page 10: Unit 4 – Immunology and Public Health Immune system.

Inflammatory Response

• Prevents – spread of injurious agents to adjacent tissues,– disposes of pathogens and dead tissue cells,– promotes tissue repair

Page 11: Unit 4 – Immunology and Public Health Immune system.

Chilblains – inflammation of the toes (or other extremities) caused by prolonged exposure to moisture and cold.

Page 12: Unit 4 – Immunology and Public Health Immune system.

Acne – inflammation of the skin caused by bacteria in the pores

Page 13: Unit 4 – Immunology and Public Health Immune system.

Inflammation is a common response to bee/wasp stings

Page 14: Unit 4 – Immunology and Public Health Immune system.

Tonsilitis – inflammation of the tonsils

Page 15: Unit 4 – Immunology and Public Health Immune system.

Mast cells are present in most tissues surrounding blood vessels and nerves, and are especially prominent near the boundaries between the outside world and the inside of our bodies, such as the skin, mucous in the lungs and digestive tract, as well as the mouth, conjunctiva, and nose.

They contain histamine and cytokines which cause the typical inflammatory response.

Page 16: Unit 4 – Immunology and Public Health Immune system.

Non-specific inflammationThe inflammatory response is triggered when something breaks the skin.

Cytokines attract white blood cells called phagocytes to the area and the release of antimicrobial proteins or clotting elements to the damaged area.

Histamines are also released which cause the capillary to vasodilate and become more permeable.

Page 18: Unit 4 – Immunology and Public Health Immune system.
Page 19: Unit 4 – Immunology and Public Health Immune system.

Copy and complete the table  FunctionMast cell  

 

Histamine   

Cytokine   

Phagocyte   

Complement   

Clotting element

  

Page 20: Unit 4 – Immunology and Public Health Immune system.

Phagocytes

Once the bacterium is inside the phagocyte, lysosomes fuse with the vesicle, digesting the bacterium.VIDEO

Phagocytes are cells which will engulf and digest a foreign particle such as bacteria.They recognise the foreign antigen molecules on its surface then bind with the bacterium and engulf it by endocytosis.

Page 21: Unit 4 – Immunology and Public Health Immune system.

Natural killer cellsNatural killer (NK) cells are found in the blood and are constantly looking for signs of an infection. They can also release cytokines but they have an important role in destroying a pathogen-infected cell.They look for a cell which has not got the normal surface antigens or self antigens and knows that it must be infected. It then destroys it with self-destructive enzymes perforating the plasma membrane, bursting it, a process called apoptosis.

Page 22: Unit 4 – Immunology and Public Health Immune system.
Page 23: Unit 4 – Immunology and Public Health Immune system.

SummarySummary

Non-specific defences

Physical and chemical defences Epithelial cells

Inflammatory response Mast cells- histaminehistamine and cytokinescytokines

Non-specific cellular responses

Phagocytosis-phagocytescytokinescytokines

NK cells- apoptosis cytokinescytokines

Page 24: Unit 4 – Immunology and Public Health Immune system.

For indiscriminate killing of pathogens

$10,000 REWARD

Phagocytes and natural killer cells Members of the notorious white blood cell gang

WANTED!

Page 25: Unit 4 – Immunology and Public Health Immune system.

Comic strip• Students will work with their shoulder partner to create a short comic strip

telling the story of how their white blood cell ended up on a wanted poster.

• The story must be biologically correct. Students must use class resources to help them.

• You have 25 minutes to come up with a storyline and produce a brief outline of your comic.

• Choose either– Phagocytes – NK

Page 26: Unit 4 – Immunology and Public Health Immune system.

Questions1. Name a secretion made by the epithelial cells lining the

inside of the body.2. What name is given to the immediate response of the

body to a cut?3. What are mast cells?4. Why do the capillaries vasodilate?5. What general name do we give disease-causing

organisms?6. Describe what an antigen is made of and where it is

found.7. What is the name of the cell signalling molecule

produced by many immune cells?

Page 27: Unit 4 – Immunology and Public Health Immune system.

Questions8. Describe the process of phagocytosis.9. What are NK cells?10.Describe the stages involved in apoptosis.

Page 28: Unit 4 – Immunology and Public Health Immune system.

Task – Create a Glossary table for the below words including their definitions

Epithelial cellsInflammatory responsePathogenAntigenNon-selfMast cellsHistaminesCytokinesVasodilation PermeabilityPhagocytesLysosomesNatural killer cellsApoptosis