Inflammation and immunity

Question 1

What different triggers would activate the inflammatory response?

Answer 1

-active damage to cells
-hypoxia or lack of nutrients to tissues
-genetic or immune defects
-chemical temperatures
-ionising radiation

Question 2

What are cytokines and provide examples of them

Answer 2

Cytokines are tissue mediators

E.g:
-histamine
-interleukin 1
-interferons
-leukotrienes
-prostaglandins
-kinins
-tumour necrosis factor alpha

Question 3

What things occur with the inflammatory response and explain why

Answer 3

1. redness= vasodilation and increased blood flow to injured site
2. swelling= damaged cells release chemicals that cause blood vessels to leak fluid into the tissues
3. pain= caused by the increased pressure from the swelling and mediators
4. fever= caused by interleukins and make it harder for pathogens to reproduce in higher temperature

Question 4

What are the two types of immunity?

Answer 4

1. humoral= involves B cells produce antibodies
2. cell mediated= involves T cells that attack proteins on the surface of infected cells

Question 5

What is the lymphatic system and what is its role?

Answer 5

-connective tissue that transports fluid from the interstitial fluid to lymphatic tissue in lymph vessels
-they produce lymphocytes to fight invading pathogens

Question 6

What 2 traits do T cells have?

Answer 6

1. self recognition= recognising cells in its own body
2. self tolerance= an ability to not respond to peptide fragments from your own proteins

Question 7

What are the first characteristic changes in circulation near the site of an injury?

Answer 7

1. chemotaxis- attracts cells to the area to help fight the infection
2. neutrophils arrive first and are phagocytes engulfing the bacteria

Question 8

What is the second characteristic change in circulation near the site of an injury?

Answer 8

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

Question 9

What is the third characteristic change in circulation near the site of an injury?

Answer 9

monocytes become macrophages as they push out of the blood vessel into tissues to hunt down the infection

Question 10

What is the fourth characteristic change in circulation near the site of an injury?

Answer 10

-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

Question 11

What is hypersensitivity?

Answer 11

An altered immune response to an antigen that causes the person to become ill or damage occurs

Question 12

What is meant by auto-immune?

Answer 12

Where the body created antibodies to fight its own cells

Question 13

What is meant by allo-immunity?

Answer 13

Where the body created antibodies in response to a foreign antigen

Question 14

What are the 4 types of hypersensitivity?

Answer 14

Type 1: IgE reactions
Type 2: Tissue specific reactions
Type 3: Immune complex mediated reactions
Type 4: cell mediated reactions

Question 15

What is sensitisation?

Answer 15

-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

Question 16

Explain in more detail what type 1 sensitisation reactions are

Answer 16

-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

Question 17

What is the first line of defence to infection?

Answer 17

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

Question 18

What is the second line of defence to infection?

Answer 18

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

Question 19

What is phagocytosis?

Answer 19

neutrophils and monocytes (phagocytes) ingest the microbe and destroy it

Question 20

What is the function of natural killer cells?

Answer 20

have the ability to kill a wide variety of cells through:

1. the antigen is transported to the lymph node
2. in the lymph node T and B cells recognise the invading microorganism by the antigen on its cell surface
3. this activates the production of immune cells to remove the infectious agent through the humeral and cellular immunity processes

Question 21

What are the 5 known types of immunoglobulins?

Answer 21

1. IgG= protect against infection antiviral, antibacterial and antitoxin
2. 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
3. IgM= helps to digest and eliminate organisms. Found in the foetus as is the first immunoglobin to be produced
4. IgD= not much known
5. IgE= found on mast cells and basophils, used against allergic reactions helping to trigger the release of histamine

Question 22

What is the difference between innate immunity compared to acquired immunity?

Answer 22

-innate immunity= is present at birth and non-specific

-acquired immunity is developed over time and specific to a particular pathogen

Question 23

What is the difference between active immunity compared to passive immunity?

Answer 23

-Active immunity= body created the antibodies to fight off a pathogen
-passive immunity= body receives antibodies from another source

Question 24

Give an example of the different types of immunity:
-natural passive
-natural active
-acquired passive
-acquired active

Answer 24

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

Question 25

What is the major histocompatibility complex?

Answer 25

-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.

Question 26

What is the function of the thymus?

Answer 26

An organ which is primarily responsible for the production and maturation of immune cells (T lymphocytes)

Question 27

What is the function of the spleen?

Answer 27

Contains infection fighting white blood cells to fight against invading pathogens in the blood stream

Question 28

How are antibodies produced?

Answer 28

Antibodies are naturally produced by plasma cells (B cells) to mediate an adaptive immune response against invading pathogens

Question 29

What is the third line of defence to infection?

Answer 29

This is the specific immune response where T and B cells target specific antigens