Immune System

Question 1

Immune system contents

Answer 1

Tonsils
Adenoids
Spleen
Lymph nodes
Lymph vessels
Thymus
Bone marrow

Question 2

Bone marrow is the site of…?

Answer 2

Haemopoiesis (forming blood cells)

Question 3

Functions of immune system

Answer 3

Recognise and kill pathogens/infected cells
Remove dead cells
Wound healing
Surveillance/removal of cancerous cells

Question 4

3 types of white blood cells

Answer 4

Granulocytes- have specific granules in cytoplasm eg neutrophils, eosinophils, basophils
Lymphocytes- T cells, B cells, natural killer cells
Monocytes- found in blood only, immature

Question 5

Neutrophils

Answer 5

Target bacteria/fungi
Found in bloodstream and tissues
First line of defence (innate, non specific)

Question 6

Eosinophils

Answer 6

Attack parasites - release hydrolytic enzymes
Involved in allergic reaction

Question 7

Basophils

Answer 7

Like Large tissue mast cells located outside capillaries in the body
Mast cells and basophils release histamines, bradykinkin and serotonin
Role in allergic reaction

Question 8

Macrophage

Answer 8

Type of white blood cell
Derived from monocytes, found in tissue e.g alveolar macrophages in lungs, microglia (macrophages of CNS)

Question 9

Innate immunity

Answer 9

Non specific, first line of defence
Neutrophils, monocytes, macrophages, granulocytes, natural killer cells
(Cell mediated)
Fast response
Phagocytosis

Question 10

3 major groups of phagocytic cells involved in innate immunity

Answer 10

Neutrophils (cytokines, chemotaxis)
Macrophages and monocytes (same cell different location)
Organ specific macrophages

Question 11

Interferons

Answer 11

Nonspecific short acting resistance to viral infection
Act as messengers that protect other cells in the vicinity from viral infection

Question 12

3 types of interferons

Answer 12

Alpha
Beta
Gamma

Question 13

Endogenous pyrogens

Answer 13

Cytokines that cause a fever eg interleukin, stimulate hypothalamus to raise temp and induce fever.
Inhibits bacteria, increases neutrophil and interferon production

Question 14

Phagocytosis

Answer 14

Phagocyte attracted to pathogen by surface antigens/chemoattractants, move via chemotaxis
Engulf pathogen in phagocytic vacuole
Lysosome fused with vacuole and releases lysozymes
Lysozymes hydrolyse pathogen
Phagocyte presents pathogens antigens on surface, becomes an antigen presenting cell

Question 15

Inflammation

Answer 15

Physiological response to infection (swelling, heat, pain, redness)
-Vasodilation to increase blood flow to effected area (increased action of neutrophils)
-increased vascular/capillary permeability, fluid leaks into interstitial spaces
-increased clotting factors
-pus formation (dead cells)
-increased production of granulocytes/monocytes by bone marrow
-walling off inflammation to specific area so infection doesn’t spread (clotting mesh formed)
-neutrophilia (overproduction of neutrophils)

Question 16

Adaptive immunity?

Answer 16

Aquired, specific to attacking pathogen
Second line of defence (Humoral)
T cells , B cells, antibodies

Question 17

2 stages of adaptive immunity

Answer 17

Cell mediated- T cells, b cells
Humoral - Antibidies

Question 18

Types of T lymphocytes

Answer 18

Helper T
Cytotoxic T/ killer T
Suppressor T
Memory T

Question 19

Activation of T lymphocytes? - MHC

Answer 19

Antigen presenting cells (e.g macrophage /phagocyte) contain MHC proteins that stick to antigen of pathogen
MHC 1 proteins present antigens to cytotoxic T cells
MHC 2 proteins present antigens to helper T cells

Question 20

Helper T cells

Answer 20

Kickstart the immune response and regulate it
Activated macrophage system
Produce lymphokines eg interleukin -1 that act on the immune system eg to stimulate macrophage production
Stimulates B cell growth- differentiation into plasma cells- antibodies
Stimulates cytotoxic T cells

Question 21

Cytotoxic T cell

Answer 21

Directly kills microorganisms / cancer cells/ sometimes own body cells
Bind to pathogen and secrete perforins, create holes in pathogen, release cytotoxic substances into cell

Question 22

Suppressor T cells

Answer 22

Suppress action of cytotoxic T cells to prevent harm to body cells

Question 23

Memory T cells

Answer 23

Produced after primary response
2nd exposure= memory T cells released, faster response

Question 24

How are b lymphocytes converted into antibodies

Answer 24

B cell- lymphoblast- plasmablast- antibodies
(Memory b cells)

Question 25

Antibodies types

Answer 25

IgE IgG IgM IgD

Question 26

Structure of antibody

Answer 26

Heavy and light chains, joined by hinge region Constant and variable region (variable= antigen binding sites at the top)

Question 27

IgE function

Answer 27

Role in Allergic response

Question 28

How do antibodies protect the body

Answer 28

Agglutinate pathogens together for easier phagocytosis Lysis of pathogens Precipitation of pathogens (make insoluble) Activate complement system

Question 29

Complement system?

Answer 29

Collective term for Group of proteins in plasma involved in immune response and fighting infection together

Question 30

Where are T cells produced?

Answer 30

Thymus

Question 31

Active immunity

Answer 31

Direct contact with the pathogen/antigen, body produces own response/antibodies. either via vaccine or naturally.

Question 32

Passive immunity

Answer 32

Antibodies given via immunisation vaccine/ passed to baby from mothers milk

Question 33

Active vs passive immunity?

Answer 33

Active: takes longer to become immune, experience symptoms of illness, produce own memory cells, longer lasting immunity Passive: faster, shorter immunity

Question 34

Immune mechanism of allergy (what happens?)

Answer 34

-Antigen presenting cells present allergens to T heler cells -T helper cells stimulate IgE production by B cells, secreted by plasma cells -IgE bind to receptors on mast cells and basophils (SENSITISATION) -When allergen antigens bind to IgE on mast cell/basophil, they are stimulated to degranulate, releasing histamines/prostaglandins/leukotrienes into bloodstream (released from granules) -causes physiological events of inflammation (vasodilation, increased vascular permeability) -more eosinophils, basophils are recruited to contribute to inflammation

Question 35

Difference between basophil and mast cell?

Answer 35

Basophils circulate in the blood whilst mast cells are found in tissues

Question 36

Anaphylaxis

Answer 36

Life threatening allergic reaction, develops rapidly , causing rapid swelling and inflammation

Question 37

Anaphylaxis triggers

Answer 37

Insect bites Food Drugs