Immune System 1

Question 1

Role of immune system

Answer 1

To protect against pathogens like viruses, bacteria or parasites
Also against altered body cells like cancer cells
Even foreign tissues like in transplants

Question 2

What two systems are involved with immunity

Answer 2

Blood (for circulation) and lymphatic system

Question 3

Branches of immune system

Answer 3

Innate/non-specific immunity: does not need to recognize pathogen to destroy it, just needs to recognize that its foreign
Adaptive/specific immunity: antibodies that can recognize specific pathogens, faster response due to immune system “memory”

Question 4

Ways that discoveries have been made in science

Answer 4

Serendipity: happy accident like small pox vaccine
Leap of faith
Accidents of nature: like discovering penicillin

Question 5

Components of the immune system (brief)

Answer 5

Lymphatic organs (primary and secondary)
Immune cells (leukocytes and WBC)
Secretions of immune cells like cytokines

Question 6

Primary and secondary lymphoid organs

Answer 6

Primary: site where stem cells divide and immune cells develop
Secondary: site where most immune responses occur

Question 7

Primary lymphoid organs

Answer 7

Bone marrow (or yolk sac/liver and spleen in embryo) where blood cells are produced, including B cells and immature T cells, this is where B cells mature
Thymus, located above the heart, contains T cells, macrophages, dendritic cells and epithelial cells
Site of T cell maturation (migrate there after synthesis in Bone marrow)
Atrophies with age (shrinks)

Question 8

Secondary lymphatic organs

Answer 8

Lymph nodes: scattered, filter microbes
How? Macrophages in nodes phagocytize microbes that enter the lymph
Spleen (largest): removes old erythrocytes and miccrobes
Lymphoid nodules: tonsils, peyers patches, MALT, appendix

Question 9

MALT

Answer 9

Mucosal- associated lymphoid tissues

Question 10

Where do immune cells travel

Answer 10

In blood and lymph nodes

Question 11

What lymphoid cells do we know

Answer 11

T cells
B cells
NK cells (natural killers)

Question 12

WBC we know and their role

Answer 12

Basophils: release chemicals like histamine and prostaglandins
Neutrophil: phagocytes
Eosinophil: destroy parasites
Monocyte: become dendritic cells and macrophages
MAST cells: release histamine

Question 13

What can monocytes become

Answer 13

Dendritic cells
Macrophages

Question 14

Mast cells vs other WBC

Answer 14

Mast cells dont circulate in blood

Question 15

Elements of the first line of defense against bacterial invaders

Answer 15

Physical barriers: skin (water proof and keratinized, epithelial cells have specialized junctions that dont let anything through), hair, mucus, cilia
Chemical and microbial: sebum, lysozyme (in sweat and tears) and gastric juice (to kill anything coming in), also teh presence of normal flora (good bacteria, only microbial barrier)

Question 16

Second line of defense against foreign invader

Answer 16

Humoral and cellular factors (discuss cellular later)
Inflammation and fever
Interferon
Antimicrobial substances: acute phase reactants like: C-reactive protein, complements and cytokines

Question 17

Signs of inflammation and what starts them

Answer 17

Redness
Heat
Swelling: edema, caused by vasodilation (increases permeability so immune cells can come) causing more ISF in tissue
Pain
Starts with vaso dilation

Question 18

Transferrin and the second line of defense

Answer 18

Transferrin the iron binding protein is over produced in times of infection because we want to lower the amount of free iron in the blood cuz bacteria/pathogens need it

Question 19

Interferon and the second line of defense

Answer 19

Works against viral infections
When a cell is infected with virus, its RNA is inserted for teh production of more viruses. Once that process begins, the victim cell released interferon, which enters blood stream and affects adjacent cells too. Will bind to cell membrane of other cells, warning them of invaders and triggering them to synthesize anti-viral proteins. If that fails and the virus does infiltrate the cell, it will not reproduce the viruses

Question 20

What do humoral substances do

Answer 20

Discourage microbial growth or spread of pathogen

Question 21

Complements in innate immunity (brief process)

Answer 21

Complement: group of proteins that complement/enhance the effect of antibodies/phagocytes
The pathogen surfaces, activating the complement, which in turn marks it through opsonization for phagocytosis which inevitably leads to killing of pathogens

Question 22

Complement C3b as an opsonin

Answer 22

Plasma protein
Binds to surface of pathogen, making the bacterium more recognizable to phagocytes
Basically mark it for death