Inflammation and immunity Flashcards
What different triggers would activate the inflammatory response?
-active damage to cells
-hypoxia or lack of nutrients to tissues
-genetic or immune defects
-chemical temperatures
-ionising radiation
What are cytokines and provide examples of them
Cytokines are tissue mediators
E.g:
-histamine
-interleukin 1
-interferons
-leukotrienes
-prostaglandins
-kinins
-tumour necrosis factor alpha
What things occur with the inflammatory response and explain why
- redness= vasodilation and increased blood flow to injured site
- swelling= damaged cells release chemicals that cause blood vessels to leak fluid into the tissues
- pain= caused by the increased pressure from the swelling and mediators
- fever= caused by interleukins and make it harder for pathogens to reproduce in higher temperature
What are the two types of immunity?
- humoral= involves B cells produce antibodies
- cell mediated= involves T cells that attack proteins on the surface of infected cells
What is the lymphatic system and what is its role?
-connective tissue that transports fluid from the interstitial fluid to lymphatic tissue in lymph vessels
-they produce lymphocytes to fight invading pathogens
What 2 traits do T cells have?
- self recognition= recognising cells in its own body
- self tolerance= an ability to not respond to peptide fragments from your own proteins
What are the first characteristic changes in circulation near the site of an injury?
- chemotaxis- attracts cells to the area to help fight the infection
- neutrophils arrive first and are phagocytes engulfing the bacteria
What is the second characteristic change in circulation near the site of an injury?
blood vessels start to become leaky which allows white blood cells to push out of the blood vessel into the surrounding tissue so that it can engulf the microorganisms around the blood vessel
-this allows small molecules to escape from the bloodstream, causing blood plasma to leak and cause swelling at the site of the injury
-blood vessels become more concentrated, creating warmth and redness at the site of inflammation
What is the third characteristic change in circulation near the site of an injury?
monocytes become macrophages as they push out of the blood vessel into tissues to hunt down the infection
What is the fourth characteristic change in circulation near the site of an injury?
-the blood vessels dilate which allows increased numbers of blood cells to get to the area to fight the infection and therefore slows the blood flow to maximise the response
What is hypersensitivity?
An altered immune response to an antigen that causes the person to become ill or damage occurs
What is meant by auto-immune?
Where the body created antibodies to fight its own cells
What is meant by allo-immunity?
Where the body created antibodies in response to a foreign antigen
What are the 4 types of hypersensitivity?
Type 1: IgE reactions
Type 2: Tissue specific reactions
Type 3: Immune complex mediated reactions
Type 4: cell mediated reactions
What is sensitisation?
-An individual becomes sensitised when sufficient T cells are produced to react to the antigen
-Initially exposure to an unknown micro-organism (antigen) will mean the person potentially develops the disease
-T and B cells learn to recognise the antigen and start to produce antibodies, so for next time the antibody response will be faster and the disease will be less severe
Explain in more detail what type 1 sensitisation reactions are
-Type 1 reactions involve IgE and are typically those seen in the respiratory system e.g hay fever, pollution, pollen etc
-This is most commonly referred to as allergies or allergic reactions but there are allergies that don’t involve IgE, and IgE is involved in other types of reactions too
-Type 1 reactions therefore occur in response to environmental allergens
-IgE is produced and the person becomes sensitised to this level
-IgE attaches to a mast cell triggering the inflammatory reaction releasing cytokines
What is the first line of defence to infection?
Physical and chemical barriers, these include
Physical:
-epidermis= secretes sebum and swear
-mucous membranes= secrete mucus
-cilia= hairs transport substances out of the body
-coughing and sneezing
-saliva
-urine flow
-defeacation
-vomiting
Chemical:
-sebum= forms acidic layer on skin
-stomach acid
-eyes produce tears from the lacrimal gland containing lysozyme
-vaginal secretions which are slightly acidic
What is the second line of defence to infection?
This is the inflammatory response, the aim is to
-localise problem
-dilute invading antigen within body fluid
-destroy invading antigen
-maintain blood vessel integrity
-minimise tissue damage
-transport required cells and substances to this area
What is phagocytosis?
neutrophils and monocytes (phagocytes) ingest the microbe and destroy it
What is the function of natural killer cells?
have the ability to kill a wide variety of cells through:
- the antigen is transported to the lymph node
- in the lymph node T and B cells recognise the invading microorganism by the antigen on its cell surface
- this activates the production of immune cells to remove the infectious agent through the humeral and cellular immunity processes
What are the 5 known types of immunoglobulins?
- IgA= a secretory immunoglobulin found in tears, saliva, colostrum, bronchial, gastrointestinal, prostatic and vaginal secretions. Acts locally on mucosa preventing viruses and bacteria entering epithelium
- IgD= not much known
- IgE= found on mast cells and basophils, used against allergic reactions helping to trigger the release of histamine
- IgG= protect against infection antiviral, antibacterial and antitoxin
- IgM= helps to digest and eliminate organisms. Found in the foetus as is the first immunoglobin to be produced
What is the difference between innate immunity compared to acquired immunity?
-innate immunity= is present at birth and non-specific
-acquired immunity is developed over time and specific to a particular pathogen
What is the difference between active immunity compared to passive immunity?
-Active immunity= body created the antibodies to fight off a pathogen
-passive immunity= body receives antibodies from another source
Give an example of the different types of immunity:
-natural passive
-natural active
-acquired passive
-acquired active
Natural passive= Newborn baby receives antibodies from their mother through colostrum
Natural active= Body responds to a disease by making antibodies
Acquired passive= Receives ready made antibodies in an urgent situation
Acquired active= Body is exposed to weakened disease so it can create the antibodies so it is prepared for exposure to the real disease
What is the major histocompatibility complex?
-A protein marker used to distinguish self cells from foreign bodies.
-MHC proteins enable the immune system to be able to specifically attack foreign pathogens as well as abnormal cells, while sparing normal cells.
What is the function of the thymus?
An organ which is primarily responsible for the production and maturation of immune cells (T lymphocytes)
What is the function of the spleen?
Contains infection fighting white blood cells to fight against invading pathogens in the blood stream
How are antibodies produced?
Antibodies are naturally produced by plasma cells (B cells) to mediate an adaptive immune response against invading pathogens
What is the third line of defence to infection?
This is the specific immune response where T and B cells target specific antigens
