Immune system

Question 1

Name some innate defenses

Answer 1

-surface barriers(skin, mucos membranes)
-internal defences (phagocytes,inflammation,antimicrobial proteins)

Question 2

What do innate/ non specific resistance defences respond to?

Answer 2

a range of pathogens or foreign substances

Question 3

Name some adaptive defenses/specific resistance

Answer 3

-humoral immunity-B cells
-cellular immunity-T cells

Question 4

What do adaptive defenses respond to?

Answer 4

a particular pathogen or foreign substance

Question 5

Name key barriers in the first line of defence

Answer 5

-mechanical (skin,mucous)
-chemical (stomach acid, lysozymes)

Question 6

Name some key components involved in the second line of defence

Answer 6

-antimicrobial proteins
-natural killer cells
-phagocytes
-inflammation
-fever

Question 7

Name some antimicrobial proteins involved in the second line of defence

Answer 7

-stomach inteferon
-complement(enhances the immune system
-transferrins(inhibit certain bacterial growth)

Question 8

What do natural killer cells do?

Answer 8

destroy cells by perforating the plasma membrane making them leaky

Question 9

Describe the role of a fever in the second line of defence

Answer 9

-the body’s thermostat in the hypothalamus is reset to a higher level
-increased temp enhances interferon, inhibits some microbial growth and speeds up repair

Question 10

What is the adaptive defence characterised by?

Answer 10

specificity- each invading agent is recognised as being different from each other
memory- a second response is faster and greater than the first

Question 11

What is specific resistance carried out by?

Answer 11

lymphocytes that originate in the bone marrow

Question 12

describe immunocompetence and self tolerance

Answer 12

once mature lymphocytes acquire specific antigen receptors that allow them to recognise specific invading agent

Question 13

Describe the antibody mediated/ humoral response

Answer 13

-B cells develop in red bone marrow

-once stimulated by an antigen, B cells clone and become plasma cells

-plasma cells produce antibodies also known as immunoglobulins

Question 14

Describe the production of antibodies

Answer 14

• specifc antigen is identified by a specific B lymphocyte

-B cells form a clone and become plasma cells

-plasma cells secrete antibodies

Question 15

What are the five classes of antibodies?

Answer 15

IgG
IgA
IgM
IgE
IgD

Question 16

What is the IgG antibody?

Answer 16

main antibody and able to cross placenta

Question 17

What is the IgA antibody?

Answer 17

secretory antibody

Question 18

What is the IgM antibody?

Answer 18

released into plasma, indicates current infection

Question 19

What is the IgE antibody?

Answer 19

associated with allergies and parasitic infections

Question 20

What is the IgD antibody?

Answer 20

attached to B cell and acts as an antigen receptor

Question 21

what are antibody mediated responses directed against?

Answer 21

extracellular pathogens such as bacteria

Question 22

Describe the cell mediated immune response

Answer 22

T cells leave bone marrow and migrate to the thymus to complete their development

-T cells become killer T cells that directly attack invading antigen
-Or they become helper T cells that help both antibody-mediated and cell mediated responses

Question 23

What are cell mediated immune response directed against?

Answer 23

intracellular pathogens such as viruses, cancer cells and tissue transplants

Question 24

Describe the role of the memory cells produced by B and T cells

Answer 24

-memory of previous invading antigens allow for the second or subsequent response to be much quicker and greater

Question 25

Whats the difference between the primary and secondary response?

Answer 25

primary- slow and innefective, signs and symptoms of the disease are seen secondary-faster and greater, signs and symptoms of the disease are not seen

Question 26

describe the two types of active humoral immunity

Answer 26

naturally acquired-infection contact with pathogen artifically acquired-vaccine dead or attenuated pathogens

Question 27

Describe two types of passive humoral immunity

Answer 27

naturally acquired-antibodies pass from mother to fetus via placenta artifically acquired-injection of immune serum (gamma globulin)

Question 28

What is the autoimmune response?

Answer 28

the body does not recognise its own tissues because it recognises them as self.

Question 29

What is immunological tolerance?

Answer 29

the body tolerates its own molecules

Question 30

Name some examples of autoimmune diseases

Answer 30

MS-destroys the mylein of the nervous system Rheumatoid arthiritis-destroys the cartilage of joints Type 1 diabetes-destroys insulin producing pancreas cells glomerulonephritis-destroys nephrons of the kidneys Myasthenia gravis-impairs communication between nerves and skeletal muscles by destroying receptor sites

Question 31

Describe the first exposure to an allergen

Answer 31

-allergen invades body -plasma cells produce large amounts of class IgE antibodies against allergen -IgE antibodies attach to mast cells in body tissues and to circulating basophils

Question 32

Describe the subsequent exposure response to an allergen

Answer 32

-more of the same antigen invades body -antigen combines with IgE attached to mast cells and basophils which trigger degranulation and release of histamines and other chemicals -histamine causes blood vesseld to dilate, promoting oedema, stimulates secretion of large amounts of mucus, causes smooth muscle to contract

Question 33

What is an anaphylatic reaction?

Answer 33

involves the breakdown of mast cells and basophils and may result in anaphylatic shock

Question 34

What is a cytotoxic reaction?

Answer 34

typical of incompatible blood transfusions resulting in destruction of cells

Question 35

What is an immune complex reaction?

Answer 35

the destruction of tissue such as rheumatoid arthirits, glomurelonephritis

Question 36

Describe delayed hypersensitivity reactions

Answer 36

appear 12-72 hours after exposure such as mantoux skin test for TB