Ch. 11

Question 1

innate immunity

Answer 1

• inborn and ancient protection
• exist in one form or another in all eukaryotic organisms
• generalized responses = don’t vary based on the pathogen being fought
• 1st and 2nd line defenses. barrier defenses, like skin or stomach acid, as well as specialized molecules, cells, and tissues
• nonspecific immunity.

Question 2

adaptive immunity

Answer 2

• newer and exists only in vertebrate animals
• includes specialized immune cells and their products—most importantly, antibodies
• set of defenses matures over time, tailoring its responses to the pathogens it encounters
• specific immunity and acquired immunity
• 3rd line defense
• remembers pathogens
• comes in when innate immune response fails

Question 3

How does normal microbiota impact immune responses and limit pathogens?

Answer 3

• play a central role in inducing, training, and calibrating immune responses
• when normal microbiota changes, our immune system may be confused and start attacking ourselves
• could be linked to rise in allergies and autoimmunity

Question 4

what do first line defenses aim to prevent?

Answer 4

pathogen entry. have mechanical, physical, and chemical barriers

Question 5

mechanical barriers

Answer 5

rinse, flush, or trap pathogens to limit their spread into the body.
Ex: tears (wash away pathogens), urine (flush them out of the body), saliva, mucous membrane

Question 6

chemical barriers

Answer 6

molecules that directly attack microbes or generate the environment that limits their survival
- lysosome: found in secretions (tears, breast milk) and breaks down bacterial cell walls
- stomach acid, pH
- antimicrobial peptides (AMPs): defensins -> kill microbial invaders. insert themselves directly in the cell wall

Question 7

physical barriers

Answer 7

structural blockage
Ex: skin and epidermis (has cells that creates barrier to prevent pathogens from entering)

Question 8

lymphatic system

Answer 8

• collection of tissues and organs
• collect, circulate, and filter fluid in body tissues before it is returned to the blood

Question 9

plasma

Answer 9

liquid portion of blood -> some will exit via capillaries

Question 10

interstitial fluid

Answer 10

plasma that seeps into spaces btw cells

Question 11

edema

Answer 11

pooling of liquid in tissues

Question 12

lymph

Answer 12

reenters lymphatic system. screened in lymph nodes and checks if lymphs have pathogens

Question 13

lymph and lymphatic vessels

Answer 13

Interstitial fluid flows into lymphatic capillaries, where it is then called lymph. Lymph flows toward lymph nodes, is filtered and screened for invading agents, and finally rejoins the venous blood supply. Upon rejoining the blood it is no longer called lymph, but is now plasma.

Question 14

granulocytes - neutrophils

Answer 14

• most numerous
• first recruits to site of infxn
• release potent antimicrobial peptides (AMPs)
  -> fight off pathogens
• phagocytize foreign cells and viruses and NETs
• elevated neutrophil count
• neutropenia = lower that normal neutrophils (signals viral infxn)

Question 15

granulocytes - eosinophils

Answer 15

• <5% of the total WBC population
• exhibit moderate phagocytic activity
• possess granules
• eosinophilia: elevated eosinophils

Question 16

granulocytes - basophils

Answer 16

• <1% of WBC population
• contain cytoplasmic granules
• role: histamine: stimulate inflammation, parasitic infxns, allergic responses

Question 17

granulocytes - mast cells

Answer 17

• reside in tissues
• release histamine
• role in allergies and fighting parasites
• conduct phagocytosis
• common in tissues near body openings (skin and mucous membranes of the airway and gastrointestinal tract)
• send out alarms to site of infxn

Question 18

phagocytes

Answer 18

(macrophages, dendritic cells, and neutrophils) target bacterial cells, viral particles, or general debris

Question 19

leukocytosis

Answer 19

increase in leukocytes. increase in the white blood cells

Question 20

monocytes

Answer 20

• Largest agranular white blood cells
• Contain horseshoe-shaped nuclei
• ~10% of circulating leukocytes
• Levels can increase due to: chronic infection
• Migrate out of the circulatory system into tissues and mature into macrophages

Question 21

macrophages

Answer 21

• Destroy a wide range of pathogens
• Fixed macrophages - relatively immotile macrophage found in connective tissue, lymph nodes, spleen, and bone marrow
• Wandering macrophages – leaves area and migrates to infected tissue

Question 22

dendritic cells

Answer 22

• Found in most body tissues
• Patrol tissues and phagocytize a broad range of antigens

Question 23

lymphocytes

Answer 23

• Natural killer cells
  
  • Abundant in the liver
  • Innate protection against viruses, bacteria,
    parasites, and even tumor cells
• T and B cells
  
  • coordinate the adaptive immune response

Question 24

how do leukocytes work with molecular factors as part of second-line defenses?

Answer 24

they buy time by slowing or outright killing the pathogen while the other parts of the immune system kick into gear

Question 25

signs of inflammation

Answer 25

redness, pain, localized heat (not fever), swelling, loss of function

Question 26

three goals of inflammation

Answer 26

recruit WBCs to injured tissue, limit spread of pathogens, deliver O2, nutrients, and chem factors

Question 27

chronic inflammation

Answer 27

- May develop when an inflammatory response goes on too long - Not useful or protective - Exacerbates tissue injury and causes further damage to tissues - Promotes atherosclerosis (disease in the arteries), certain cancers, and progressive neurodegenerative disorders

Question 28

what is a fever?

Answer 28

a systemic innate immune response - controversy regarding treatment of low-grade fever - low grade= 99.5-101F - has protective effects - fever reaches 105F

Question 29

studies suggest what about fevers?

Answer 29

increase efficiency of interferons, increase efficiency of phagocytes, limit growth of pathogens, promotes tissue repair

Question 30

complement cascades

Answer 30

- innate -> not specific to any pathogen - consists of >30 different proteins = work together in cascade fashion - circulate in the blood in activate form - when activated, a cascade of events result in a boost to the immune system

Question 31

complement cascade outcomes

Answer 31

1. opsonization: invader has been tagged w/ a protein so it stands out to WBCs 2. cytolysis: MAC -> membrane attack complex 3. inflammation

Question 32

iron-binding proteins

Answer 32

- hemoglobin: RBCs, transport oxygen - ferritin: found in most body cells - lactoferrin: milk, tears, mucous, saliva - transferrin: found in blood plasma and extracellular fluids

Question 33

what is iron?

Answer 33

vital nutrient for most cells

Question 34

cytokines

Answer 34

- signaling proteins - allow cells to communicate w/ one another - coordinate immune response

Question 35

chemokines

Answer 35

- signaling - attract WBC -> serve to attract WBC to a site of infxn - induce chemotaxis - >40 known chemokines Aid in: wound healing, blood vessel, lymphoid tissue development, activate both parts of immune response

Question 36

interleukins (ILs)

Answer 36

- activate adaptive and innate immune responses - stimulate hematopoiesis: stimulates production of new blood cells and platelets - IL-1 family: neg inflammation, stimulate adaptive and innate response, generates fever - IL-2 family: T cells develop, self tolerance, trigger apoptosis (programmed cell death)

Question 37

interferons (IFNs)

Answer 37

- send out signals when tumor/pathogen/virus is detected - can also trigger apoptosis Ex) virus-infected cells make IFN-alpha and IFN-beta as alarms that stimulate nearby uninfected cells to mount antiviral defenses

Question 38

tumor necrosis factors (TNFs)

Answer 38

- signaling proteins - TNF-alpha - made primarily by macrophages -> monocytes that migrated to tissues - role: stimulate inflammation, kill tumor cells, stimulate fever - TNF-α inhibitors treat certain immune disorders (e.g., rheumatoid arthritis, IBS)

Question 39

3 roles of second-line molecular defenses

Answer 39

cytokines, iron-binding proteins, complement proteins

Question 40

3 general phases of inflammation

Answer 40

- vascular changes: chemical alarm signals released by damaged cells and leukocytes increase blood flow and vessel permeability - leukocyte recruitment: cytokines recruit leukocytes. neutrophils arrive first, followed by monocytes, which mature into macrophages. neutrophils and macrophages phagocytize invaders and recruit other leukocytes - resolution: inflammation signals decrease; tissue repair initiated