Lymphatic system abridged Flashcards
1
Q
First Line of Defense (Innate, nonspecific, defense mechanisms)
A
- Skin
- Mucous membranes
- Secretions of skin and mucous membranes
2
Q
Second Line of Defense (Innate, nonspecific, defense mechanisms)
A
- Phagocytic cells
- Antimicrobial proteins
- The inflammatory response
- Natural Killer Cells
- Fever
3
Q
Third Line of Defense (Adaptive, specific, defense mechanisms)
A
- Lymphocytes
- Antibodies
- Macrophages
4
Q
Phagocytes
A
- Engulfs foreign particle, enclosing it in a vacuole
- Fuses with enzymatic contents of lysosome
- Particle’s contents are broken or digested
5
Q
Natural Killer Cells
A
- Lyse and kill cancer cells, virus-infected body cells, and other non-specific targets before adaptive defense system is activated
- Not phagocytic: attack target’s membrane and release perforins
- Target’s membrane and nucleus then disintegrate
6
Q
Four signs of inflammation
A
- Heat
- Swelling
- Pain
- Redness
7
Q
Inflammatory chemicals released at site of injured tissue/cells
A
- Histamine
- Kinins
8
Q
Inflammatory process (chemical alarm)
A
Chemical “alarm” is sounded at injured site, releasing histamine and kinins. Effects:
- Blood vessels dilate
- Capillaries become leaky
- Pain receptors activated
- Chemotaxis: attract phagocytes and WBCs to area
9
Q
Complement
A
- Group of plasma proteins that circles blood in inactive state
- When it attaches to foreign cells, it becomes activated and helps destroy it via lysis
- Membrane Attack Complexes (MAC attack) put lesions in cell membranes so water rushes in and they lyse
10
Q
Interferons
A
- Proteins released by virus-infected cells that prevent spread of virus
- Diffuse to nearby cells and bind to their membrane receptors
- Stimulate synthesis of proteins that interfere with virus’ ability to multiply within healthy cells
11
Q
Complete antigenic substances
A
- Foreign proteins (strongest)
- Nucleic Acids
- Many large carbohydrates
- Some lipids
- Pollen grains & microorganisms (bacteria, fungi, and virus particles) are antigenic because surfaces have foreign molecules
12
Q
Two arms of Adaptive (Specific) Defense System
A
1) Humoral Immunity (antibody-mediated immunity)
2) Cellular Immunity (cell-mediated immunity)
13
Q
Humoral Immunity (antibody-mediated immunity)
A
- Provided by antibodies present in body’s “humors,” or fluids
- B lymphocytes produce antibodies and oversee humoral immunity
14
Q
Cellular Immunity (cell-mediated immunity)
A
- Cells defend the body (macrophages, antigen-specific Cytotoxic T lymphocytes, etc.)
- T lymphocytes are non-antibody producing lymphocytes
15
Q
B cells
A
- Lymphocytes residing in lymph nodes, spleen, or other lymphoid tissues
- Replicates after binding with an antigen or at command of helper T cell
- Most become plasma cells, some become memory cells
- Antigen-presenting cells
16
Q
Helper T cell
A
- Binds with a specific antigen presented by an APC
- Stimulates production of cytotoxic/killer T cells and B cells to help fight the invader
- Releases cytokines which enhance everything
17
Q
Cytotoxic/Killer T cell
A
- Kills virus-invaded body cells and cells that have become cancerous
- Also contain perforin
- Involved in graft rejection
18
Q
Regulatory T cell
A
- Slows or stops activity of B and T cells once infection or attack has been conquered
- Important in preventing autoimmune disease
19
Q
Plasma cell
A
Produces huge numbers of the same antibody (immunoglobulin)
20
Q
Memory cell
A
- Generated during the initial immune response (primary response)
- May exist in the body for years thereafter, enabling it to respond quickly and efficiently to subsequent infections or meetings with the same antigen
21
Q
Macrophages
A
- Engulf foreign particles and rid them from the area
- Antigen-presenting cells
- Most effective in presence of cytokines (secreted by helper T cells and macrophages)
22
Q
IgM
A
- Attached to B cell or free in plasma
- When bound to B cell, serves as antigen receptor
- First to be released to plasma by plasma cells during primary response
- Potent agglutinating agent
- Fixes complement
23
Q
IgA
A
- Some (monomer) in plasma; others in secretions (saliva, tears, intestinal juice, and milk)
- Bathes and protects mucosal surfaces from attachment of pathogens
24
Q
IgD
A
- Always attached to B cell
- Cell surface receptor of immunocompetent B cell, helps activate it
25
IgG
- Most abundant antibody in plasma (75-85% of circulating antibodies)
- Main antibody of primary and secondary responses
- Crosses placenta to give passive immunity to fetus
- Fixes complement
26
IgE
- Secreted by plasma cells in skin, mucosae of GI and respiratory tracts, tonsils
- Binds to mast cells and basophils
- Triggers release of histamine and other chemicals that mediate inflammation and certain allergic responses
27
Four ways antibodies act against antigens
- Complement fixation
- Agglutination
- Precipitation
- Neutralization
28
Complement fixation
- Complement is fixed/activated during innate defenses
- Very efficient when it binds to antibodies attached to cellular targets
- Can lead to MAC attack: creates holes on foreign cell's surface, allowing water to rush in and burst cell
29
Agglutination
- Clumping of foreign cells
| - Occurs when mismatched blood is transfused
30
Neutralization
- Antibodies bind to specific sites on bacterial toxic chemicals or on viruses that can cause cell injury
- Block harmful effects of chemicals or virus
31
Precipitation
- Cross-linking process of antigen-antibody complex
- Result is so large that they become insoluble and settle out of solution
Immobilized antigen molecules (more easily captured and engulfed)
32
Active Immunity
- When our B cells encounter antigens and produce antibodies against them
- Naturally acquired during bacterial and viral infections
- Artificially acquired when we receive vaccines
33
Passive Immunity
- Antibodies obtained from the serum of an immune human or animal donor
- B cells are NOT challenged by antigen
- Immunological memory does NOT occur
- Temporary protection provided by “borrowed antibodies” ends when they degrade in the body
- Naturally acquired: mom to fetus
- Artificially acquired: injection of immune serum
34
Antimicrobial substances
- Complement proteins
- Interferons
- Fluids with acid pH
35
Inflammatory process, post-alarm (3 steps)
1. ) Neutrophils enter blood and travel along vessel walls, following scent
2. ) Diapedesis: they flatten out and squeeze through capillary wall where scent is strongest
3. ) Positive chemotaxis: they gather at injury site and devour foreign material
36
Important aspects of adaptive defense (3)
1. It is antigen-specific
2. It is systemic
3. It has memory
37
Cytokines
- Stimulate cytotoxic T cells and B cells to grow and divide
- Attract other types of protective WBCs to area (neutrophils)
- Enhance ability of macrophages to engulf and destroy; increase their appetite
