Immune 1 Flashcards
What is immunology?
The study of an organisms defence system (immune system) in health and diesease
What is the immune system composed of?
- organs (spleen)
- cells (T cells)
- molecules (anitbodies)
What is the immune system?
- an organised system of organs, cells and molecules that interact together to defend the body against diesease (eg pthogenic microorganisms and cancer)
Examples of diseases affected by the immune response: INFECTIOUS DISEASES
- HIV/AIDS 3
- Tuberculosis 1
- Influenza
- Malaria 4
- SARS-CoV-2 1
Examples of diseases affected by the immune response : Inflammatory diseases
- arthritis / rheumatism
- allergy / asthma
- lupus
- diabetes
- Crohn’s disease / inflammatory bowel disease
- multiple sclerosis
Examples of diseases affected by the immune response : cancer
Cancer
Main types of microbes - smallest to largest
- viruses - (are simple and everywhere - needs a host cell to replicate from)
- bacteria - (more self sufficient and complicated then viruses and can replicate independently )
- fungi
- Protozoa
Are microbes disease causing?
Some microbobes are disease causing (pathogens)
- most that are around are not disease causing (like microbes in your gut)
The ________ sytstem is important for ______ and _____ _________ around the body and that helps link together the organs of the immune system
The lymphatic sytstem is important for moving and shuttling immune cells around the body and that helps link together the organs of the immune system
(From lecture talking)
Organs of the immune system
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Two types of organs of the immune system
Primary and secondary
Primary: production of white blood cells (lymphocytes)
Secondary: sites where immune responses are initiated
Primary lymphoid organs
Thymus:
- “school” for white blood cells called T cells
- developing T cells learn not to react to self (only about 10% of cells that go in come out as mature T cells)
Bone morrow:
- source of stem cells that develop into cells of the ‘innate’ and ‘adaptive’ immune responses
Secondary lymphoid organs
Lymph nodes:
- located along lymphatic vessels
- lymph fluid from blood and tissue is filtered (lymphatic vessels are there to take lymph fluid from tissue and recirculate the cells through the blood and back into the tissue and they can move around the body)
- site of initiation of immune responses (specifically for tissue rather then blood
Spleen:
- site of initiation for immune responses against blood-borne pathogens (as it is where blood is filtered)
3 layers of defence
1: chemical physical barriers that stop pathogens from getting into our bodies
2: innate ‘arm’ - fast acting
3: adaptive arm - slower, can adapt and change as an immune response is occurring
Physical and chemical Barriers:
Skin and mucosal surfaces
The skin - dermis and epidermis
Epidermis - dead cells, keratin and phagocytic immune cells - constant renewal of the outer layer thus removing pathogens with it
Dermis - thick layer of connective tissue, collagen and blood vessels and phagocytic immune cells
Dendritic cell (immune cells in this layer) - lie within alive layer that sits at the bottom of the epidermis - ((they have a large surface area so they are good at interacting with other cells and alerting them that something is going on ))
Chemical defences of the skin
- skin produces antimicrobial peptides e.g skin ‘ defensins’ which forms pores in microbial cell membranes which leads to them dying
- skin produces enzyme called lysozyme which breaks down bacterial cell walls
- sebaceous glands (which are associated with hair follicales and they produce sebum lowers the pH giving the skin acidity - hostile environment fro bacteria to grow in
- sweat glands produces salty sweat which makes a hypertonic environment which desiccates bacteria
Mucous membranes
- found in parts of body that are exposed to air - eyes - intestinal tracts
- 1-2 layers
- epithelium: tightly packed live cells, constantly renewed, mucus-producing goblet cells (produces the mucous that forms the layer across the epithelium
- on top of live cell layer there is a thin layer of mucus keeping outer layer wet and trap microbobes
Where are mucosal membranes?
Ocular, respiratory, oral, urogenital/rectal
- Mucosal membranes line parts of the body that lead to the outside and are exposed to air
The mucoiliary escalator
Cilia act to move mucus up to the pharynx
- beat together in unison to move mucus up to the pharynx to cough up what we’ve inhaled and most of the time swallow it - helps get rid of any organisms that have tried to get into the lung
Chemical defences of mucosal surfaces
- stomach - low pH
- gall bladder - bile
- intestine - digestive enzymes
- mucus
- defensins
- lysozyme (tears, urine)
Two intertwined ‘arms of the immune system
- innate defences
- adaptive defences
They are constantly in dialogue
Which is more specific? Innate or adaptive?
Adaptive arm
Innate defences include
Surface barriers:
- skin
- mucous memebranes
Internal defences:
- phagocytes - eat things up
- natural killer cells
- inflammation
- antimicrobial proteins
- fever
Adaptive defences include
Two different cell types
Humoral immunity
- B cells - make antibodies
Cellular immunity
- T cells - mediate cellular immunity
Differences between innate and adaptive immunity
Innate immunity features
- already in place
- rapid (hours) -
- fixed
- limited specificities (detects molecular components shared by many pathogens) - receptors on surface are fixed
- has no specific memory
Adaptive immunity
- improves during the response
- slow (days —-> weeks)
- variable
- highly specific (detects molecular components specific to individual pathogens) - can change receptors
- has memory
