Chapter 22 - Lympathic System & Immunity Flashcards
1
Q
What are pathogens?
A
Disease-producing microbes
- bacteria or viruses
2
Q
What is immunity or resistance?
A
Ability to ward off damage or disease through our defenses
3
Q
What is susceptibility?
A
Vulnerability or lack of resistance
4
Q
What are the two general types of immunity?
A
- Innate (nonspecific immunity)
2. Adaptive (specific immunity)
5
Q
What is innate (nonspecific) immunity?
A
Defenses that are present at birth
- acts against all microbes the same way
6
Q
What are the components of innate (nonspecific) immunity?
A
- First line of defense (skin and mucous membranes)
2. Second line of defense (antimicrobial substances, natural killer cells, phagocytes, inflammation, fever)
7
Q
What is the function of innate (nonspecific) immunity?
A
- early warning system
- prevent microbes from gaining access
- help eliminate those microbes that do gain access
8
Q
What is adaptive (specific) immunity?
A
Defenses that involve special recognition of a microbe
- once it has breached the innate immunity defenses
9
Q
What does adaptive (specific) immunity involve?
A
Lymphocytes
- a type of white blood cell
- T cells and B cells
10
Q
Why is adaptive (specific) immunity named the way it is?
A
Specific response for a specific microbe
- its adjusts/adapts to handle a specific microbe
11
Q
What does the lymphatic system consist of?
A
- lymph
- lymphatic vessels (transport lymph)
- structure and organs containing lymphatic tissue
- red bone marrow
12
Q
What is lymph?
A
The fluid of the lymphatic system
13
Q
What is lymphatic tissue?
A
Specialized form of reticular connective tissue
- contains a large number of lymphocytes (agranular white blood cell)
14
Q
What two types of lymphocytes are adaptive to immune responses?
A
- B cells
2. T cells
15
Q
What are the three functions of the lymphatic system?
A
- Drains excess interstitial fluid into blood
- Transports dietary lipids
- Carries out immune responses
16
Q
Generally summaries lymphatic circulation.
A
Lymph passes from lymphatic capillaries into lymphatic vessels (thin walls and more valves than veins) and then through lymph nodes (consisting of B cells & T cells)
17
Q
What are the tissues that lack lymphatic capillaries?
A
- cartilage
- epidermis
- cornea of the eye
- CNS
- portions of spleen
- red bone marrow
18
Q
How do lymphatic capillaries differ from blood capillaries?
A
- greater permeability
- slightly larger diameter
- unique one-way structure (interstitial fluid)
19
Q
What are lacteals?
A
Specialized lymphatic capillaries, in the small intestine
- carry dietary lipids into lymphatic vessels and ultimately the blood
20
Q
What is chyle?
A
Lymph in the small intestine
- appears creamy white due to presence of lipids
21
Q
What colour is lymph normally?
A
Clear, pale-yellow fluid
22
Q
What happens after lymphatic vessels exit lymph nodes?
A
They unite to form lymph trunks
23
Q
What are the five principal lymph trunks?
A
- Lumbar
- Intestinal
- Bronchomediastinal
- Subclavian
- Jugular
24
Q
After lymph passes from lymph trunks, where does it go?
A
Into two main channels
- thoracic (left lymphatic) duct
- right lymphatic duct
25
What is the Thoracic (left lymphatic) duct?
THE main channels that lymph passes through before draining into venous blood
26
What is the cisterna chyli?
A dilation where the thoracic (left lymphatic) duct begins
27
Where does the thoracic (left lymphatic) duct receive lymph from?
- left side of the head, neck, chest
- left upper limb
- entire body inferior to the ribs
28
Where does the thoracic duct drain lymph into venous blood?
At the junction of the left internal jugular and subclavian veins
29
Where does the right lymphatic duct receive lymph from?
- right side of the head, neck, chest
| - right upper limb
30
Where does the right lymphatic duct drain lymph into venous blood?
At the junction of the right internal jugular and right subclavian veins
31
How is lymph formed?
More fluid filters out of capillaries than returns to them be reabsorption (approx. 3 liters), so it drains into lymphatic vessels and becomes lymph
32
What is the sequence of fluid flow in the lymphatic system?
Blood capillaries --> interstitial spaces (interstitial fluid) --> lymphatic capillaries (lymph) --> lymphatic vessels --> lymphatic ducts --> junction of the internal jugular and sublcavian veins --> returns to blood
33
What maintains the flow of lymph?
1. Skeletal muscle pump
| 2. Respiratory pump
34
How does the skeletal muscle pump aid in the flow of lymph?
"Milking action" of skeletal muscle contractions compresses lymphatic vessels and forces lymph toward the junction of the internal jugular and subclavian veins
35
How does the respiratory pump aid in the flow of lymph?
Maintained by the pressure changes that occur during inhalation
- lymph flows from abdominal region (high pressure) towards the thoracic region (low pressure)
- valves prevents back-flow during exhalation
36
What are the two groups of classifications of lymphatic organs and tissues?
1. Primary lymphatic organs
| 2. Secondary lymphatic organs and tissues
37
What are primary lymphatic organs?
Sites where stem cells divide and become immuno-competent
38
What does immuno-competent mean?
Capable of mounting an immune response
39
What are the names of the primary lymphatic organs?
- red bone marrow (in flat bones and epiphyses of long bones in adults)
- thymus
40
What happens at the secondary lymphatic organs and tissues?
Sites where most immune responses occur
41
What are the names of the secondary lymphatic organs and tissues?
- lymph nodes
- spleen
- lymphatic nodules (follicles)
42
What is the function of the thymus in the lymphatic system?
Vital role in the training and development of T-lymphocytes (T cells)
- a type of white blood cell
43
What is the route taken by lymph as it flows through a lymph node?
Afferent lymphatic vessel --> Subcapsular sinus --> Travecular sinus --> Medullary sinus --> Efferent lymphatic vessel
44
Approximately how many lymph nodes do we have?
600
45
Where are the areas of the body that have a large number of lymph nodes grouped together?
- Mammary glands
- Axillae
- Groin
46
What is a capsule?
| What does it cover?
Dense connevtive tissue that covers lymph nodes
47
What are trabeculae?
Capsule extensions
| - divide the node into compartments, provide support, provide route for blood vessels into the vessel
48
What is within the outer cortex of lymphatic nodes?
Aggregates of B cells (lymphatic nodules)
49
What are lymphatic nodules (follicles)?
Small, localized collection of lymphatic tissue
50
What is a primary lymphatic nodule?
A lymphatic nodule consisting mainly of B cells
51
What is the function of dendritic cells?
Assist in the maturation process of T cells in the thymus
52
What is the function of thymic macrophages?
Help clear out the debris of dead and dying cells
| - T cells that did not manage to mature
53
What does the inner cortex consist of?
| in a lymph node
- T cells
| - Dendritic cells that enter a lymph node from other tissues
54
What is the function of a B cell?
A lymphocyte not processed by the thymus gland, and responsible for producing antibodies.
55
What is the function of a T cell?
A lymphocyte of a type produced or processed by the thymus gland and actively participating in the immune response.
56
What does the medulla of a lymph node consist of?
- B cells
- antibody producing plasma cells
- macrophages
57
What is the function of afferent lymphatic vessels?
Contain valves that open toward the center of the node, directing lymph INWARD
- penetrate the convex surface of the node at several points
58
What are sinuses?
| lymph nodes
A series of irregular channels that contain branching reticular fibers, lymphocytes and macrophages
59
What is the function of efferent lymphatic vessels?
Contain valve that open away from the center of the node, directing lymph AWAY from the node
- wider and fewer in number than afferent vessels
60
What is a hilum?
A slight depression where efferent lymphatic vessels emerge from one side of the lymph node
61
What is the single largest mass of lymphatic tissue in the body?
Spleen
62
What two kinds of tissue does the spleen consist of?
1. White pulp
| 2. Red pulp
63
What is white pulp?
Lymphatic tissue of the spleen
| - mostly lymphocytes and marcrophages
64
What is red pulp?
Blood-filled venous sinuses and cords of splenic tissue
65
What is the function of red pulp as related to blood cells?
1. Removal by macrophages of ruptured, worn-out, or defective blood cells
2. Storage of platelets (1/3 of body supply)
3. Production of blood cells during fetal life
66
What are lymphatic nodules (follicles)?
Egg-shaped masses of lymphathic tissue that are not surrounded by a capsule
- scattered throughout gastrointestinal, urinary, reproductive tracts, respiratiory
67
What are lymphatic nodules (follicles) also referred as?
MALT
| - mucosa-associated lymphatic tissue
68
How many tonsils do we have?
5
69
What is the function of tonsils?
Participate in immune responses against inhaled or ingested foreign substances
70
What are tonsils?
Aggregation of lymphatic nodules
71
Name the 5 tonsils.
1. Single Pharyngeal tonsil (x1)
2. Two palatine tonsils (x2)
3. Paired lingual tonsils (x2)
72
What is the first line of defense against pathogens?
Skin and mucous membrane
73
How does the epidermis contribute to the skins' defenses?
Closely packed keratinized cells provide a formidable physical barriers
- not effective if the surface is broken (cut, scrape, burn)
74
Where are mucous membranes found and what do they secrete?
Line body cavities
| - secrete mucous
75
What is the function of mucous?
Lubricates and moistens the cavity surface
| - traps microbes and foreign substances
76
What does the nose contain that helps protect against foreign objects, microbes and pollutants?
Mucous-coated hairs
| - trap and filter inhaled air
77
How do the cilia in the upper respiratory tract remove foreign objects?
Waving action of cilia propels inhaled dust and microbes towards the throat
- coughing and sneezing accelerate this movement
78
How does the lacrimal apparatus help protect the body?
Manufactures and drains away tears in response to irrantants
| - blinking spreads tears over the surface of the eye, continual washing dilutes microbes
79
What is lysozyme? How does it help to protect the body?
An enzyme that is capable of breaking down the cell walls of certain bacteria
- present in saliva, perspiration, nasal secretions and tissue fluids
80
How does saliva help protect the body?
Washes microbes from the surface of teeth and from mucous membrane of the mouth
- flow of saliva reduces colonization of microbes
81
How does the urethra remain clean?
By the flow of urine
| - slows microbial colonization in the urinary system
82
How does defecation and vomiting help protect the body?
By expelling microbes
83
What is sebum? How does it protect the body?
Secretion from oil glands
| - forms a protective film over the surface of the skin
84
How does perspiration protect the body?
Helps to flush microbes from the surface of the skin
85
How do gastric juices protect the body?
Strong acidity of gastric juices destroys many bacteria and most bacterial toxins
86
How do vaginal secretions help protect the body?
Slightly acidic, discourages bacterial growth
87
What are the four main types of antimicrobial substances that discourage microbial growth?
1. Interferons
2. Complement
3. Iron-binding proteins
4. Antimicrobial proteins
88
What cells release interferons?
1. Lymphocytes
2. Macrophages
3. Fibroblasts
89
What are interferons?
Proteins released by certain cells in response to a virus
| - able to inhibit virus replication
90
What are the three types of interferons?
1. Alpha-IFN
2. Beta-IFN
3. Gamma-IFN
91
What is the complement system of immunity?
Proteins that "complement" or enhance certain immune responses
- contributes to inflammation
- promotes phagocytosis
- causes cytolysis (bursting) of microbes
92
How do iron-binding proteins inhibit the growth of bacteria?
By reducing the amount of available iron
93
What are examples of iron-binding proteins?
1. Transferrin (in blood and tissue fluids)
2. Lactoferrin (in milk, saliva, mucous)
3. Ferritin (in liver, spleen, red bone marrow)
4. Hemoglobin (in red blood cells)
94
How do antimicrobial proteins (AMPs) protect the body?
- kills a wide variety of microbes
- attract dendritic cells and mast cells (which participate in immune responses)
- microbes do NOT develop resistance against AMPs
95
What are some example of AMPs?
- Dermicidin (produced by sweat glands)
- Defensins and Cathelicidins (produced by neutrophils, macrophages and epithelia)
- Thrombocidin (produced by platelets
96
If a microbe penetrates the skin and gets past the antimicrobial substances in the blood, what is the next line of defense?
1. Natural killer (NK) cells
| 2. Phagocytes
97
What are natural killer (NK) cells?
Lymphocytes that has the ability to kill a wide variety of infected body cells and certain tumor cells
- attack any body cell that displays abnormal or unusual plasma membrane proteins
98
Where are natural killer cells found?
Spleen, lymph nodes, red bone marrow
99
What is perforin?
A protein that natural killer cells inserts into the plasma membrane of the target cell
- creates channels (perforations) in the membrane
100
How does perforin kill cells?
Channels allow extracellular fluid to flow into the cell, they burst (cytolysis)
101
What are phagocytes?
Specialized cells that perform phagocytosis
| ingestion of microbes or other particles
102
What are the two main types of phagocytes?
1. Neutrophils
2. Macrophages
- both types migrate to infected areas
103
What are the two kinds of macrophages?
1. Wandering macrophages (move around)
| 2. Fixed macrophages (present in specific tissues)
104
What are the five phases of phagocytosis?
1. Chemotaxis
2. Adherence
3. Ingestion
4. Digestion
5. Killing
105
What is chemotaxis?
| Stage of Phagocytosis
A chemically stimulated movement of phagocytes to a site of damage
- from invading microbes, white blood cells, damaged tissue cells or activated complement proteins
106
What is adherence?
| Stage of Phagocytosis
Attachment of the phagocytes to the microbe or foreign substance
- binding of complement proteins to invading pathogens enhances adherence
107
What is ingestion?
| Stage of Phagocytosis
Pseudopods (plasma membrane projections) engulf the microbe
| - surround the microbe in a phagosome (a sac)
108
What is digestion?
| Stage of Phagocytosis
Phagosome merges with lysosomes to form a phagolysosome
| - breaks down microbial cell walls
109
What is killing?
| Stage of Phagocytosis
Chemical onslaught provided by the lysosome
| - kills the microbes
110
What is inflammation?
| What are the conditions that cause inflammation?
Nonspecific, defensive response to tissue damage
| - pathogens, abrasions, chemical irritations, distortion, extreme temperatures
111
What are the four characteristic signs and symptoms of inflammation?
1. Redness
2. Pain
3. Heat
4. Swelling
112
What is a common cause of inflammation to an injured area?
Loss of function
| - ex. inability to detect sensations
113
What are the three basic stages of the inflammatory response?
1. Vasodilation and increased permeability of blood vessels
2. Emigration (movement) of phagocytes from blood into interstitial fluid
3. Tissue repair
114
Why is vasodilation and increased blood vessel permeability important to the inflammatory response?
Vasodilation - allows more blood to flow through the damaged area (increased blood flow also helps to remove microbial toxins and dead cells)
Increased permeability - allows defensive proteins (antibodies and clotting factors) to enter the damaged area
115
What are the five other aspects of the inflammatory response?
1. Histamine
2. Kinins
3. Prostaglandins
4. Leukotriens
5. Complement
116
What is histamine and what does it do?
Compound released by cells in response to injury, allergic and inflammatory reactions
- causes contraction of smooth muscle and dilation of capillaries
117
What are kinins and what do they do?
Polypeptides
| - cause vasodilation, increased permeability and smooth muscle contraction
118
What are prostaglandins and what do they do?
Lipids
- intensify the effects of histamine and kinins
- stimulate the emigration of phagocytes through capillary walls
119
Where are leukotrienes produced and what do they do?
Produced by basophils and mast cells
- cause increased permeability
- also function in adherence and as chemotactic agents that attract phagocytes
120
What do complement do in the inflammatory response?
- stimulate histamine release
- attract neutrophils by chemotaxis
- promote phagocytosis
- destroy bacteria
121
What is emigration?
Movement of phagocytes from blood into interstitial fluid
| - neutrophils squeeze through the wall of the blood vessel to reach the damaged area
122
What does emigration depend on?
Chemotaxis
123
What is leukocytosis?
Increase in white blood cells from red bone marrow
124
What is pus?
Collection of dead cells and fluid
| - dead macrophages/phagocytes
125
What is a fever?
| Why does it occur?
Abnormally high body temperature
- occurs because the hypothalamic thermostat is reset
- occurs during infection and inflammation
126
What three effects does a fever have on the body?
- intensifies the effects of interferons
- inhibits the growth of some microbes
- speeds up body reactions that aid repair
127
What are antigens (Ags)?
Substances that generate an immune response
| - bacteria, toxins, viruses, foreign substances
128
What two properties distinguish adaptive immunity fro innate immunity?
1. SPECIFICITY for particular foreign molecules, which also involves distinguishing self from non-self molecules
2. MEMORY for most previously encountered antigens
129
Why is memory so important to adaptive immunity?
A second encounter prompts an even more rapid and vigorous response
130
What cells are involved in adaptive immunity?
B cells
| T cells
131
How do B cells mature?
- Develop in primary lymphatic organs (red bone marrow and thymus)
- Complete development in red bone marrow
132
How do T cells mature?
- develop from pre-T cells that migrate from red bone marrow
- migrate into the thymus where they mature
- Thymus = T cells
133
What is immunocompetence?
The ability to carry out adaptive immune responses
134
What are antigen receptors?
Proteins in the plasma membranes of B cells and T cells
| - molecules capable of recognizing specific antigens
135
What are the two types of adaptive immunity?
1. Cell-mediated immunity
2. Antibody-mediated immunity
- both are triggered by antigens
136
What happens during cell-mediated immunity responses?
Cytotoxic T cells directly attack invading antigens
137
What happens during antibody-mediated immunity responses?
B cells transform into plasma cells, which synthesize and secrete specific proteins (antibodies)
138
What are antibodies?
| immunoglobulins
Specific proteins that can bind to and inactivate a specific antigen
139
What is cell-mediated immunity effective against?
- INTRAcellular pathogens (viruses, bacteria, fungi)
- some cancer cells
- foreign tissue transplants
140
What is antibody-mediated immunity effective against?
- EXTRAcellular pathogens (viruses, bacteria, fungi)
141
What are two important characteristics of antigens?
1. Immunogenicity
| 2. Reactivity
142
What is immunogenicity?
The ability to provoke an immune response by stimulating the production of specific antibodies, the proliferation of specific T cells, or both
143
What is reactivity?
The ability of the antigen to react specifically with the antibodies or cells it provoked
144
What are the substances called that exhibit both immunogenicity and reactivity?
Complete antigens
145
What are epitopes?
Small parts of a large antigen molecule that act as the triggers for immune responses
146
What are the three routes that antigens take to enter the body?
1. Enter the bloodstream; trapped by the spleen
2. Penetrate the skin; enter lymphatic vessels and lodge in lymphatic nodes
3. Penetrate mucous membranes; trapped by mucosa-associated lymphatic tissues (MALT)
147
What is a hapten?
A smaller substance that can stimulate an immune response only if it is attached to a larger carrier molecule
- has reactivity but lacks immunogenicity
148
What are major histocompatibility complex (MHC) antigens?
"Self-antigens"
- located in the plasma membrane of body cells
- unique to each individual
149
What is the function of major histrocompatibility complex (MHC) antigens?
To help T cells recognize that an antigen is foreign, not self
150
When are B cells able to recognize and bind to antigens?
In lymph, interstitial fluid or blood plasma
151
When are T cells able to recognize fragments of antigenic proteins?
Only when they are processed and presented in a certain way
152
What are exogenous antigens?
Foreign antigens that are present in fluids OUTSIDE body cells
- bacteria, bacterial toxins, parasitic worms, pollen, dust, viruses that have not yet entered a cell
153
What are antigen-presenting cells (APCs)?
```
Special class of cells
- process and present exogenous antigens
```
154
What do antigen-presenting cells (APCs) include?
- dendritic cells
- macrophages
- B cells
155
Where are APCs located?
Epidermis and dermis of the skin
Mucous membranes (lungs, intestines, urinary, reproductive)
Lymph nodes
156
What are endogenous antigens?
Foreign antigens that are present INSIDE body cells
| - viral proteins, toxins from intracellular bacteria, abnormal proteins from cancer
157
What are cytokines?
Small proteins hormones that stimulate or inhibit many normal cell functions (cell growth or differentiation)
158
What does a cell-mediated immune response begin with?
| And what are the next steps?
Activation of a small number of T cells by a specific antigen
- once a T cell is activated, it undergoes clonal selection
- some clones become effector cells, other become memory cells
- effector cells result in elimination of the intruder
159
What is clonal selection?
The process where a lymphocyte divides and differentiates (forms more highly specialized cells) in response to a specific antigen
160
What are T-cell receptors (TCRs)?
Antigen receptors on the surface of T cells recognize and bind to specific foreign antigen fragments that are presented in antigen-MHC complexes
161
What is costimulation?
A process where a T cell only becomes activated if it binds to the foreign antigen and at the same time receives a SECOND SIGNAL
162
What is interleukin-s?
A costimulator
| - activates T cells
163
What kind of cells develop into helper T cells?
T cells that display CD4
| - also known as CD4 T cells
164
What is the function of INACTIVE helper T cells?
Recognize exogenous antigen fragments associated with major histocompatibility complex class II (MHC-II) at the surface of an APC
165
What is the function of an ACTIVE helper T cell?
Helper T cell undergoes clonal selection
| - consists of active helper T cells and memory helper T cells
166
What do ACTIVE helper T cells secrete?
Cytokines
| - example: interleukin-2
167
What is a memory helper T cell?
NOT an active helper T cell
| - able to quickly proliferate and differentiate if the same antigen enters the body in the future
168
What kinds of cells develop into cytotoxic T cells?
T cells that display CD8
169
What is the function of CD8 T cells?
Recognize foreign antigens combined with MHC-I molecules on the the surface of:
- body cells infected with microbes
- some tumor cells
- cells of a tissue transplant
170
What are the cells that function in the elimination of invaders in cell-mediated immune responses?
Cytotoxic T cells
| - "soliders"
171
What is the major difference between cytotoxic T cells and natural killer cells?
Cytotoxic T cells have receptors specific to a particular microbe and thus kill only target body cells infected with ONE particular type of microbe
- natural killer cells destroy a wide variety
172
What is cytolysis?
A cell bursting
| - example: due to perforin creating channels, allowing extracellular matrix to flow in and burst the cell
173
What is lymphotoxin?
Toxic molecule released by cytotoxic T cells to destroy target cells
- causes the target cell's DNA to fragment and the cell dies
174
What are tumor antigens?
Novel cell surface components that are displayed when a normal cell transforms into a cancerous cell
- rarely displayed on the surface
175
What is immunological surveillance?
Process where the immune system recognizes a tumor antigen as nonself, it can destroy any cancer cells carrying that antigen
176
What kinds of cells carry out immunological surveillance?
- cytotoxic T cells
- macrophages
- natural killer cells
177
During the activation of a B cell (during antibody-mediated immunity), what does the antigen bind to?
B-cell receptors
178
What are B-cell receptors?
Integral transmembrane proteins that are chemically similar to the antibodies that are eventually secreted by plasma cells
179
What are the steps in antibody-mediated immunity responses?
1. In the presence of a foreign antigen, a SPECIFIC B cell in a lymph node, the spleen, or mucosa-assoicated lymphatic tissue become activated
2. Undergoes clonal selection - forming a clone of plasma cells and memory cells
3. Plasma cells are the effector cells of a B cell clone, secrete SPECIFIC antibodies
4. Antibodies circulate in lymph and blood to reach the site of invasion
180
What do plasma cells secrete during an antibody-mediated response?
Antibodies
181
What is the function of memory B cells during an antibody-mediated response?
Quickly proliferate and differentiate into more plasma cells and more memory B cells if the same antigen reappears in the future
- does NOT secrete antibodies
182
What can an antibody combine with?
The epitope on that antigen that triggered its production
| - like a lock and key
183
What are antibodies also known as?
Immunoglobulins
| - belong to a group of glycoproteins
184
What two shapes can an antibody assume?
| Why?
T shape or a Y shape
- made of 4 polypeptide chains, 2 heavy, 2 light
- disulfide bond holds it all together, creates a "hinge"
185
Where is the antigen-binding site on an antibody?
The tips of the H and L chains; the variable (V) regions
186
How many binding sites does an antibody typically have?
2
| - why they are called bivalent
187
List the five actions of antibodies.
1. Neutralizing antigen
2. Immobilizing bacteria
3. Agglutinating and precipitating antigen
4. Activating complement
5. Enhancing phagocytosis
188
What does it mean to neutralize an antigen?
Reaction of an antibody with an antigen blocks or neutralizes some bacterial toxins and prevents attachment of some viruses to body cells
189
What does it mean to immobile bacteria?
When antibodies form against antigens on the cilia or flagella of motile bacteria, they lose their mobility
190
What does it mean to agglutinate and precipitate an antigen?
Since antibodies have two binding sites, the antigent-antibody reaction may cause agglutination (clumping together)
- may be more easilty phagocytized when antigens come out of a solution (precipitate)
191
What does it mean to activate a complement?
Antigen-antibody complexes initiate the classical pathway of the complement system
192
What does it mean to enhance phagocytosis?
Stem region of an antibody acts as a flag that attracts phagocytes, once antigens have bound to the antibody's variable region
193
What is the role of the complement system in immunity?
Defensive system
| - complement proteins destroy microbes by causing phagocytosis, cytolysis and inflammation
194
What are the three ways that C3 (part of complement system) can be activated?
1. Classical pathway - antibodies bind to antigens
2. Alternative pathway - does not involve antibodies
- interaction between lipid-carbohydrate complex on the surface of the microbes
3. Lectin pathway - lectins bind to carbohydrates on the surface of microbes, ultimately causing the activation of C3
195
What is the primary immune response?
Following the first exposure to a foreign antigen, a lag phase occurs in which no antibody is produced, but activated B cells are differentiating into plasma cells
196
What is the secondary immune response?
Immunological memory has been established and the immune system can start making antibodies immediately
- usually before we are even aware that we were attacked
197
In order to function properly, T cells must exhibit these two traits.
1. Self-recognition
| 2. Self-tolerence
198
What is self-recognition?
Able to recognize your own MHC-complex proteins
199
What is self-tolerence?
Lack reactivity to peptide fragments from your own proteins
200
Which hormone, secreted by the adrenal cortex inhibits the immune system?
Cortisol - in associated with the stress response
201
What is AIDS?
Acquired immunodeficiency syndrome
- the progressive destruction of the immune system by the human immunodeficiency virus (HIV)
- end stage of HIV
202
What does it mean to be allergic?
Overly reactive to a substance that is tolerated by most other people
203
What are the 4 types of allergic reaction?
1. Anaphylactic reactions -constricted airway
2. Cytotoxic
3. Immune-complex
4. Cell-mediated
204
What is an auto-immune disease?
Immune system fails to display self-tolerance and attacks the person's own tissues
205
What is infectious mononucleosis?
Contiguous disease caused by EBV (epstein-barr virus)
- characterized by swelling of the lymph glands and prolonged lassitude
- "mono"
206
What is systemic lupus erythematosus?
| "Lupus"
Chronic autoimmune, inflammatory disease that affects multiple body systems
- marked by inflammation of the skin
207
What is chronic fatigue syndrome?
- extreme fatigue that impairs normal activities
| - absence of any other disease that might cause the symptoms
208
What is a gamma globulin?
Suspension of immunoglobulins from blood
- consisting of anitbodies that react with a specific pathogen
- provides short-term immunity
