Immune System Part 1

Question 1

Primary Lymphoid Tissues

Answer 1

Development of immune cells

• Bone Marrow: maturation of B cells
• Thymus Gland: maturation of T cells
• Size and activity peaks in adolescence and may disappear in old age

Question 2

Secondary Lymphoid Tissues

Answer 2

Site rich in active immune cells

-Can be encapsulated or diffuse

Question 3

Encapsulated Secondary lymphoid tissues

Answer 3

Surrounded by connective tissue
Spleen-filters damaged cells and microorganisms from blood
Lymph Nodes- filter fluid captured from interstitial spaces

Question 4

Diffuse Secondary lymphoid tissues

Answer 4

Aggregation of immune cells, not encapsulated
-Tonsils-filter out inhaled/ingested pathogens
Mucosa associated lymphoid tissue, gut associated lymphoid tissue (GALT)

Question 5

Main Components of Pathogen Defense (3)

Answer 5

1 . Physical and chem barriers (skin, tears, saliva, etc)

2. Innate Immunity
3. Adaptive Immunity

Question 6

Innate Immunity

Answer 6

Non-specific defenses, respond to pathogens and tissue damage

Question 7

Adaptive Immunity

Answer 7

Specific defenses, recognize and respond to specific pathogens

Question 8

Jobs of Complement Cascade

Answer 8

Identify bacteria
Activate additional immune cells
Promote clearance of dead cells or antibody complexes

Question 9

Activation of adaptive immune system via APC

Answer 9

Dendritic cells and macrophages

• Toll-like receptors on APC recognize foreign molecule
• Macrophages also respond to phosphatidylserine, a signal for apoptotic cells

Question 10

Inflammatory response

Answer 10

occurs when there is damage or invasion which has penetrated the skin

• 4 signs: rubor, tumor, calor (heat), dolor (pain)
• Attracts immune cells and chem mediators
• Produce phys barrier to prevent spread of infection
• promote tissue repair (increased blood flow)

Question 11

Main jobs of Innate Immunity

Answer 11

• Recruits immune cells to sites of infection and inflammation (produce cytokines)
• Activation of complement cascade
• Identification and removal of foreign substances by WBCs
• Activation of adaptive immune system (via APC)
• Inflammatory response

Question 12

Inflammatory Response Molecules (5)

Answer 12

• Acute phase proteins
• Histamine
• Interleukins
• Bradykinin
• Complement

Question 13

Acute Phase Proteins

Answer 13

Immediate response proteins in plasma

• Many produced by liver
• Opsonins that coat pathogens, antiproteases, that prevent tissue damage
• Persist long-term in chronic inflammation (atherosclerosis)
• Inflammatory response molecule

Question 14

Histamine

Answer 14

Released by mast cells and basophils in response to cytokines

• initiation of inflammation
• causes dilation and leakiness of capillaries

Question 15

Interleukins

Answer 15

Specific class of cytokines

• IL-1 secreted by macrophages and other immune cells
• Alters blood vessel endothelium to allow WBC to site
• Stimulate liver to make acute phase proteins
• Induces fever
• Stimulate cytokine and endocrine secretion

Question 16

Bradykinin

Answer 16

Vasodilator and stimulator of pain receptors

Question 17

Inflammatory Response Sequence

Answer 17

1. Antibodies (produced by B lymphocytes) bind to antigens of pathogen to mark pathogen for phagocytosis
2. Mast cells in the area respond to the infection and signal by releasing heparin, histamine, prostaglandins, leukotrienes
3. Neurophils are the 1st to arrive and kill the pathogen and signal for other immune cells to come
4. Monocytes arrive later and eat dead neutrophils and pathogen and debris

Question 18

Signals released by mast cells at site of infection

Answer 18

• Heparin: anticoagulant
• Histamine: bronchiolar constriction, vasodilation and increase in vascular permeability
• Prostaglandins -lead to pain and fever (IL1)
• Leukotrienes: bronchiolar constriction, vasoconstriction, increase in vascular permeability

Question 19

Complement System

Answer 19

• More than 25 plasma proteins
• Create holes in bacteria cell walls
• Mark bacteria for phagocytosis
• Stimulate mast cells to release histamine

Question 20

Steps of Complement System Activation (3)

Answer 20

1. Recognition: C1 becomes activated by antibodies
2. Activation: hydrolytic activation cascade of C4, C2, and C3
3. Attack: C5-C9 organize into the pores w/in pathogen membrane (membrane attack complex)

Question 21

Alternate Pathway

Answer 21

Slower activation of complement system based on unique carbs on pathogen surgace
-Leads to common activation of C3

Question 22

Classical Pathway

Answer 22

Activation of complement system

• Initiated by antibody opsonization on pathogens
• Begins w/ C1

Question 23

C3a and C5b in complement cascade

Answer 23

Stimulate histamine release

Question 24

C5b in complement cascade

Answer 24

Chemokin trail for neutrophils and monocytes/macrophages

Question 25

Natural Killer Cells

Answer 25

Destroy viral infected and cancer cells - Induce apoptosis - Secrete interferons

Question 26

Interferon

Answer 26

Can protect cells from viral infections - Interferon alpha and beta stimulate production of antiviral proteins - Interferon gamma stimulate macrophages and other immune cells

Question 27

Pyrogens

Answer 27

Trigger fever | -Can be exogenous (released by pathogens) or endogenous (released by immune cells)

Question 28

Benefits of fever

Answer 28

- Unbearable environment for some pathogens - Stimulate WBC proliferation - Enhanced leukocyte phagocytosis - Increase proliferation of T cells - Enhanced activity of interferon

Question 29

Reye Syndrome

Answer 29

Neurological disorder triggered by a viral infection