1.86k likes | 2.19k Vues
Pathogens. Microscopic organisms that cause disease:virusesbacteriafungiparasitesEach attacks in a specific way . The Lymphatic System Protects us against disease . Lymphocytes:Lymphatic system cells respond to:environmental pathogenstoxinsabnormal body cells, such as cancers . What is the difference between nonspecific and specific defense, and the role of lymphocytes in the immune response?.
E N D
1. Chapter 22: The Lymphatic SystemBiology 142 A&PR.L. Brashear-Kaulfers
2. Pathogens Microscopic organisms that cause disease:
viruses
bacteria
fungi
parasites
Each attacks in a specific way
3. The Lymphatic SystemProtects us against disease Lymphocytes:
Lymphatic system cells respond to:
environmental pathogens
toxins
abnormal body cells, such as cancers
4. What is the difference between nonspecific and specific defense, and the role of lymphocytes in the immune response?
5. Specific Defenses Lymphocytes:
part of the immune response
Identify, attack, and develop immunity to a specific pathogen
Immunity- The ability to resist infection and disease
6. The Immune System All body cells and tissues involved in production of immunity:
not just lymphatic system
7. Nonspecific Defenses Block or attack any potential infectious organism
Cannot distinguish one attack from another
8. Organization of the Lymphatic System
9. 4 Parts of the Lymphatic System Lymph:
a fluid similar to plasma
does not have plasma proteins
Lymphatic vessels (lymphatics):
network that carries lymph from peripheral tissues to the venous system
Lymphoid tissues and lymphoid organs:
found throughout the body
Lymphocytes, phagocytes, and other immune system cells
10. Function of the Lymphatic System To produce, maintain, and distribute lymphocytes-
**Lymphocyte Production:
- Lymphocytes are produced:
in lymphoid tissues (e.g., tonsils)
lymphoid organs (e.g., spleen, thymus)
and in red bone marrow
** Lymphocytes Distribution:
detect problems
travel into site of injury or infection
11. Lymphocyte Circulation From blood to interstitial fluid (lymph) through capillaries
Returns to venous blood through lymphatic vessels
12. The Circulation of Fluids From blood plasma to lymph and back to the venous system
Also transports hormones, nutrients, and waste products
13. Lymphatic Vessels Are vessels that carry lymph
Lymphatic system begins with smallest vessels: lymphatic capillaries (terminal lymphatics)
Lymphatic Capillaries-
Differ from blood capillaries in 4 ways:
start as pockets rather than tubes
have larger diameters
have thinner walls
flat or irregular in section
14. Lymphatic Capillaries
15. Lacteals Are special lymphatic capillaries in small intestine
Transport lipids from digestive tract
16. Lymphatic Vessels and Valves
17. Lymph Flow From lymphatic capillaries to larger lymphatic vessels containing one-way valves
Lymphatic vessels travel with veins
18. Lymphatic Ducts and the Venous System
19. The Lymphatic System Is divided into:
1) Superficial lymphatics - located in:
skin
mucus membranes
serous membranes lining body
2) Deep lymphatics- Are larger vessels that accompany deep arteries and veins
20. Superficial and Deep Lymphatics Join to form large lymphatic trunks
Trunks empty into 2 major collecting vessels:
thoracic duct
right lymphatic duct
21. The Inferior Thoracic Duct Collects lymph from:
left bronchiomediastinal trunk
left subclavian trunk
left jugular trunk
Empties into left subclavian vein
The Right Lymphatic Duct
Collects lymph from:
right jugular trunk
right subclavian trunk
right bronchiomediastinal trunk
Empties into right subclavian vein
22. Lymphedema Blockage of lymph drainage from a limb
Causes severe swelling
Interferes with immune system function
23. Why are lymphocytes important, and how are they distributed in the body? Lymphocytes
Make up 20–30% of circulating leukocytes
Most are stored, not circulating
24. 3 Classes of Circulating Lymphocytes T cells: thymus-dependent
Make up 80% of circulating lymphocytes
2. B cells: bone–marrow derived
Make up 10–15% of circulating lymphocytes
Differentiate into plasma cells- Produce and secrete antibodies (immunoglobin proteins)
3. NK cells:
natural killer cells
25. 3 Main Types of T Cells Cytotoxic T cells-Attack cells infected by viruses
Produce cell-mediated immunity
2. Helper T cells- Stimulate function of T cells and B cells
3. Suppressor T cells-Inhibit function of T cells and B cells
26. Regulatory T Cells Are helper and suppressor T cells
Control sensitivity of immune response
Other T Cells
Inflammatory T cells
Suppressor and inducer T cells
27. Antigens Targets which identify any pathogen or foreign compound
Immunoglobin Proteins (Ig’s)
Also called antibodies (Ab)
The binding of a specific antibody to its specific target antigen initiates antibody-mediated immunity:
- A chain of events which destroys the target compound or organism
28. Natural Killer (NK) Cells Also called large granular lymphocytes
Make up 5–10% of circulating lymphocytes
Responsible for immunological surveillance
Attack:
foreign cells
virus-infected cells
cancer cells
29. Lymphocyte Distribution Tissues maintain different T cell and B cell populations
Lymphocytes wander through tissues:
enter blood vessels or lymphatics for transport
can survive many years
30. Production and Distribution of Lymphocytes
31. Lymphopoiesis Lymphocyte production involves:
bone marrow
thymus
peripheral lymphoid tissues
Hemocytoblasts : In bone marrow, divide into 2 types of lymphoid stem cells
32. Lymphoid Stem Cells Group 1:
remain in bone marrow
produce B cells and natural killer cells
Group 2:
migrate to thymus
produce T cells in environment isolated by blood-thymus barrier
33. T Cells and B Cells Migrate throughout the body:
to defend peripheral tissues
Retain their ability to divide:
is essential to immune system function
34. Differentiation B cells differentiate:
with exposure to hormone interleukin-7
T cells differentiate:
with exposure to several thymic hormones
Interleukin-7 - A cytokine produced by stromal cells in bone marrow
35. What are the structures and functions of lymphoid tissues and organs?Lymphoid Tissues :Connective tissues dominated by lymphocytes
36. Lymphoid Nodules
37. Lymphoid Nodule Areolar tissue with densely packed lymphocytes
Germinal center contains dividing lymphocytes
38. Distribution of Lymphoid Nodules Lymph nodes
Spleen
Respiratory tract (tonsils)
Along digestive and urinary tracts
39. Mucosa-Associated Lymphoid Tissue (MALT) Lymphoid tissues associated with the digestive system:
aggregated lymphoid nodules:
clustered deep to intestinal epithelial lining
Appendix:
mass of fused lymphoid nodules
40. The 5 Tonsils In wall of pharynx:
left and right palatine tonsils
pharyngeal tonsil (adenoid)
2 lingual tonsils
41. Lymphoid Organs Lymph nodes
Thymus
Spleen
Are separated from surrounding tissues
By a fibrous connective-tissue capsule
42. Lymph Nodes Range from 1–25 mm diameter
43. Afferent Lymphatic Vessels Carry lymph:
from peripheral tissues to lymph node
Efferent Lymphatic Vessels
Leave lymph node at hilus
Carry lymph to venous circulation
44. Lymph from Afferent Lymphatics Flows through lymph node in a network of sinuses:
From subcapsular sinus:
contains macrophages and dendritic cells
Through outer cortex:
contains B cells within germinal centers
Through deep cortex:
dominated by T cells
Through the core (medulla):
contains B cells and plasma cells
organized into medullary cords
Into hilus and efferent lymphatics
45. Lymph Node A filter:
purifies lymph before return to venous circulation
Removes:
debris
pathogens
99% of antigens
46. Antigen Presentation First step in immune response
Extracted antigens are “presented” to lymphocytes:
or attached to dendritic cells to stimulate lymphocytes
47. Lymphoid Functions Lymphoid tissues and lymph nodes:
distributed to monitor peripheral infections
respond before infections reach vital organs of trunk
48. Lymph Nodes of Gut, Trachea, Lungs, and Thoracic Duct Protect against pathogens in digestive and respiratory systems
Lymph Glands
Large lymph nodes at groin and base of neck
Swell in response to inflammation
49. Lymphadenopathy Chronic or excessive enlargement of lymph nodes may indicate infections, endocrine disorders, or cancer
50. The Thymus
51. The Thymus Located in mediastinum
Deteriorates after puberty:
diminishing effectiveness of immune system
Divisions of the Thymus Thymus is divided into 2 thymic lobes
Septa divide lobes into smaller lobules
52. A Thymic Lobule Contains a dense outer cortex
And a pale central medulla
Thymus Hormones
Thymosins
Promote development of lymphocytes
53. Lymphocytes Divide in the cortex
T cells migrate into medulla
Mature T cells leave thymus by medullary blood vessels
54. Reticular Epithelial Cells in the Cortex Surround lymphocytes in cortex
Maintain blood-thymus barrier
Secrete thymic hormones that stimulate:
stem cell divisions
T cell differentiation
55. Reticular Epithelial Cells in the Medulla Form concentric layers (Hassall’s corpuscles)
The medulla has no blood–thymus barrier:
T cells can enter or leave bloodstream
56. The Spleen
57. 3 Functions of the Spleen Removal of abnormal blood cells and other blood components by phagocytosis
Storage of iron recycled from red blood cells
Initiation of immune responses by B cells and T cells:
in response to antigens in circulating blood
58. Structure of the Spleen Attached to stomach by gastrosplenic ligament
Contacts diaphragm and left kidney
Splenic veins, arteries, and lymphatic vessels:
communicate with spleen at hilus
59. Structure of the Spleen Inside fibrous capsule:
Red pulp: contains many red blood cells
Contains elements of circulating blood plus fixed & free macrophages
White pulp: resembles lymphoid nodules
60. Trabecular Arteries Branch and radiate toward capsule
Finer branches surrounded by white pulp
Capillaries discharge red blood cells into red pulp
61. Splenic Circulation Blood passes through:
network of reticular fibers
Then enters large sinusoids (lined by macrophages):
which empty into trabecular veins
62. Spleen Function Phagocytes and other lymphocytes in spleen:
identify and attack damaged and infected cells
in circulating blood
63. Body Defenses Provide resistance to fight infection, illness, and disease
2 categories of defenses:
nonspecific defenses = Always work the same way , against any type of invading agent
specific defenses = Protect against specific pathogens
Depend on activities of lymphocytes
Specific resistance (immunity):
develops after exposure to environmental hazards
64. 7 Types of Nonspecific Resistance Physical barriers
Phagocytic cells
Immunological surveillance
Interferons
Complement
Inflammation
Fever
65. Nonspecific and Specific Defenses Operate together to provide resistance to infection and disease
66. The 7 Nonspecific Defenses
67. The 7 Nonspecific Defenses Physical Barriers -Keep hazardous materials outside the body
Phagocytes -Attack and remove dangerous microorganisms
Immunological Surveillance -Constantly monitors normal tissues:
with natural killer cells (NK cells)
Interferons -Trigger production of antiviral proteins in normal cells
Antiviral proteins:
do not kill viruses
block replication in cell
68. The 7 Nonspecific Defenses Complement (C) Proteins -Form the complement system
Complements action of antibodies
Inflammation -Triggers a complex inflammatory response
Fever -A high body temperature:
increases body metabolism
accelerates defenses
inhibits some viruses and bacteria
69. What are the components and mechanisms of each nonspecific defense?
70. Physical Barriers Outer layer of skin
Hair
Epithelial layers of internal passageways
Secretions that flush away materials:
sweat glands, mucus, and urine
Secretions that kill or inhibit microorganisms:
enzymes, antibodies, and stomach acid
71. 2 Classes of Phagocytes Microphages: neutrophils and eosinophils
Leave the bloodstream
Enter peripheral tissues to fight infections
Macrophages: large phagocytic cells derived from monocytes
Distributed throughout body
Make up monocyte–macrophage system (reticuloendothelial system)
72. Activated Macrophages Respond to pathogens in several ways:
engulf pathogen and destroy it with lysosomal enzymes
bind to pathogen so other cells can destroy it
destroy pathogen by releasing toxic chemicals into interstitial fluid
73. 2 Types of Macrophages Fixed macrophages - also called histocytes: Microglia:
found in central nervous system
Kupffer cells:
found in liver sinusoids
Stay in specific tissues or organs:
e.g., dermis and bone marrow
Free macrophages -Travel through blood stream
Special free macrophages:
alveolar macrophages (phagocytic dust cells)
74. 3 Functional Characteristics of Free Macrophages and Microphages Move through capillary walls (emigration)
Are attracted or repelled by chemicals in surrounding fluids (chemotaxis)
Phagocytosis begins:
when phagocyte attaches to target (adhesion)
and surrounds it with a vesicle
75. Natural Killer Cell Function
76. NK Cell Function Identifies and attaches to abnormal cell (non-selective)
Golgi apparatus in NK cell:
forms perforin vesicles
Vesicles release perforin (exocytosis)
Perforin lyses abnormal cell membrane
77. NK Cells attack: cancer cells and cells infected with viruses 1) Cancer Cells -with tumor specific antigens:
are identified as abnormal by NK cells
some cancer cells avoid NK cells (immunological escape)
2) Viral Infections : Cells infected with viruses:
present abnormal proteins on cell membranes
allow NK cells to identify and destroy them
78. Interferons Proteins (cytokines) released by activated lymphocytes and macrophages-
Cytokines - Chemical messengers released by tissue cells:
to coordinate local activities
to act as hormones to affect whole body
79. 3 Types of Interferons Alpha interferons:
produced by leukocytes
stimulate NK cells
Beta interferons:
secreted by fibroblasts
slow inflammation
Gamma interferons:
secreted by T cells and NK cells
stimulate macrophage activity
80. Complement Activation
81. Complement Activation Complements work together in cascades
2 pathways activate the complement system
classical pathway
alternative pathway
82. The Classical Pathway Fast method
C1 binds to antibody molecule attached to antigen (bacterium)
Bound protein acts as enzyme:
catalyzes chain reaction
83. The Alternative Pathway Slow method
Exposed to antigen:
factor P (properdin)
factor B
and factor D interact in plasma
** Both pathways end with:
conversion of inactive complement protein (C3)
to active form (C3b)
84. 4 Effects of Complement Activation Stimulation of inflammation
Attraction of phagocytes
Enhancement of phagocytosis by opsonization:
complements working with antibodies (opsonins)
Destruction of target cell membranes:
5 complement proteins join to form membrane attack complex (MAC)
85. Inflammation Also called inflammatory response
A localized response
Triggered by any stimulus that kills cells or injures tissue
86. Cardinal Signs and Symptoms Swelling (tumor)
Redness (rubor)
Heat (calor)
Pain (dolor)
87. 3 Effects of Inflammation Temporary repair and barrier against pathogens
Retards spread of pathogens into surrounding areas
Mobilization of local and systemic defenses:
and facilitation of repairs (regeneration)
88. Inflammation and Tissue Repair
89. Inflammation and Tissue Repair Injured cells release:
prostaglandins
proteins
potassium ions
Changes interstitial environment and stimulates mast cells
Mast cells release:
histamine (increases capillary permeability)
heparin (inhibits clotting
90. Inflammation and Tissue Repair Increased blood flow:
raises local temperature
causes area to swell, redden, and become painful
Blood clot forms around damaged area, isolating it
Complements:
break down bacteria
attract phagocytes
91. Inflammation and Tissue Repair Activated neutrophils attack debris and bacteria
Phagocytes and foreign proteins:
activate body’s specific defense system
Macrophages clean up pathogens and cell debris
Fibroblasts form scar tissue
92. Products of Inflammation Necrosis:
local tissue destruction in area of injury
Pus:
mixture of debris and necrotic tissue
Abscess:
pus accumulated in an enclosed space
93. Fever - A maintained body temperature above 37°C (99°F) Pyrogens - Any material that causes the hypothalamus to raise body temperature:
circulating pathogens, toxins, or antibody complexes
Endogenous Pyrogens : Interleukin-1 (IL-1)
pyrogen released by active macrophages
a cytokine
94. Forms of Immunity
95. Specific Defenses Specific resistance (immunity):
responds to specific antigens
with coordinated action of T cells and B cells
96. T Cells Provide cell-mediated immunity
Defends against abnormal cells and pathogens inside cells
97. B Cells Provide antibody-mediated immunity
Defends against antigens and pathogens in body fluids
98. Forms of Immunity 1) Innate Immunity:
present at birth
2) Acquired Immunity:
after birth
Active:
antibodies develop after exposure to antigen
Passive:
antibodies are transferred from another source
99. Active Immunity Naturally acquired:
through environmental exposure to pathogens
Induced:
through vaccines containing pathogens
100. Passive Immunity Naturally acquired:
antibodies acquired from the mother
Induced:
by an injection of antibodies
101. 4 Properties of Immunity Specificity- Each T or B cell:
responds only to a specific antigen, ignores all others
Versatility-The body produces many types of lymphocytes:
each fights a different type of antigen (Ag)
active lymphocyte clones itself to fight specific Ag
Memory-Some active lymphocytes (memory cells):
stay in circulation
provide immunity against new exposure
Tolerance- Immune system ignores “normal” antigens
102. What are the differences between cell-mediated (cellular) immunity and antibody-mediated (humoral) immunity?
103. The Immune Response
104. The Immune Response 2 main divisions:
cell mediated immunity (T cells)
antibody mediated immunity (B cells)
105. What are the types of T cells and their functions in the immune response?
106. What are the types of T cells and their functions in the immune response? 1) Cytotoxic T Cells= also called Tc cells
Attack cells infected by viruses
Responsible for cell-mediated immunity
2) Helper T Cells= also called Th cells
Stimulate function of T cells and B cells
3) Suppressor T Cells = also called Ts cells
Inhibit function of T cells and B cells
107. Antigens and MHC Proteins
108. Antigen Recognition T cells only recognize antigens that are bound to glycoproteins in cell membranes
109. Antigen Presentation
110. MHC Proteins The membrane glycoproteins that bind to antigens
Genetically coded in chromosome 6:
the major histocompatibility complex (MHC)
differs among individuals
111. 2 Classes of MHC Proteins Class I: found in membranes of all nucleated cells
Pick up small peptides in cell and carry them to the surface:
T cells ignore normal peptides
abnormal peptides or viral proteins activate T cells to destroy cell
Class II: found in membranes of antigen-presenting cells (APCs)
found in lymphocytes Antigenic fragments:
from antigenic processing of pathogens
bind to Class II proteins
inserted in cell membrane to stimulate T cells
112. Antigen-Presenting Cells (APCs) Responsible for activating T cells against foreign cells and proteins
Phagocytic APCs :
Free and fixed macrophages:
in connective tissues
Kupffer cells:
of the liver
Microglia:
in the CNS
113. Pinocytic APCs Langerhans cells:
in the skin
Dendritic cells:
in lymph nodes and spleen
114. What are the mechanisms of T cell activation and the differentiation of the major classes of T cells?
115. An Overview of the Immune Response
116. Antigen Recognition Inactive T cell receptors:
recognize Class I or Class II MHC proteins
recognize a specific antigen
Binding occurs when MHC protein matches antigen
117. CD Markers Also called cluster of differentiation markers:
in T cell membranes
molecular mechanism of antigen recognition
more than 70 types:
designated by an identifying number
CD3 Receptor Complex
Found in all T cells
118. CD8 Markers Found on cytotoxic T cells and suppressor T cells
Respond to antigens on Class I MHC proteins
CD4 Markers
Found on helper T cells
Respond to antigens on Class II MHC proteins
CD8 or CD4 Markers - Bind to CD3 receptor complex
Prepare cell for activation
119. Costimulation For T cell to be activated, it must be costimulated:
by binding to stimulating cell at second site
which confirms the first signal
120. 2 Classes of CD8 T Cells Activated by exposure to antigens on MHC proteins:
one responds quickly:
producing cytotoxic T cells and memory T cells
the other responds slowly:
producing suppressor T cells
121. Activation of Cytotoxic T Cells
122. Actions of Cytotoxic T Cells Release perforin:
to destroy antigenic cell membrane
Secrete poisonous lymphotoxin:
to destroy target cell
Activate genes in target cell:
that cause cell to die
123. Slow Response Can take up to 2 days from time of first exposure to an antigen, for cytotoxic T cells to reach effective levels
124. Memory Tc Cells Produced with cytotoxic T cells
Stay in circulation
Immediately form cytotoxic T cells:
if same antigen appears again
125. Suppressor T Cells Secrete suppression factors
Inhibit responses of T and B cells
After initial immune response
Limit immune reaction to single stimulus
126. Activation of Helper T Cells
127. 4 Functions of Cytokines Stimulate T cell divisions:
produce memory T cells
accelerate cytotoxic T cell maturation
Attract and stimulate macrophages
Attract and stimulate NK cells
Promote activation of B cells
128. Pathways of T Cell Activation
129. KEY CONCEPT Cell-mediated immunity involves close physical contact between activated Tc cells and foreign, abnormal or infected cells
T cell activation usually involves:
antigen presentation by phagocytic cell
costimulation by cytokines from active phagocytes
Tc cells may destroy target cells through local release of cytokines, lymphotoxins, or perforin
130. What are the mechanisms of B cell activation and the differentiation of plasma cells and memory B cells?
131. B Cells Responsible for antibody-mediated immunity
Attack antigens by producing specific antibodies
Millions of populations, each with different antibody molecules
132. B Cell Sensitization Corresponding antigens in interstitial fluids bind to B cell receptors
B cell prepares for activation
Preparation process is sensitization
133. B Cell Sensitization and Activation
134. Helper T Cells Sensitized B cell is prepared for activation, but needs helper T cell activated by same antigen
B Cell Activation
Helper T cell binds to MHC complex:
secretes cytokines that promote B cell activation and division
135. B Cell Division Activated B cell divides into:
plasma cells -Synthesize and secrete antibodies into interstitial fluid
Memory B cells- Like memory T cells remain in reserve to respond to next infection
136. Antibody Structure
137. Antibody Structure 2 parallel pairs of polypeptide chains:
1 pair of heavy chains
1 pair of light chains
Each chain contains:
constant segments
variable segments-Determine specificity of antibody molecule
138. 5 Heavy-Chain Constant Segments Determine 5 types of antibodies:
IgG
IgE
IgD
IgM
IgA
139. Binding Sites Free tips of 2 variable segments:
form antigen binding sites of antibody molecule
which bind to antigenic determinant sites of antigen molecule
140. Antibody Function
141. A Complete Antigen Has 2 antigenic determinant sites
Binds to both of antigen binding sites of variable segments of antibody
Exposure to a complete antigen leads to:
B cell sensitization
immune response
142. A Hapten Also called partial antigen
Must attach to a carrier molecule to act as a complete antigen
Dangers of Haptens
Antibodies produced attack both hapten and carrier molecule
If carrier is “normal”:
antibody attacks normal cells
e.g., penicillin allergy
143. 5 Classes of Antibodies
144. 5 Classes of Antibodies Also called immunoglobins (Igs)
Are found in body fluids
Are determined by constant segments
Have no effect on antibody specificity
145. 7 Functions of Antigen–Antibody Complexes Neutralization of antigen binding sites
Precipitation and agglutination:
formation of immune complex
Activation of complement
Attraction of phagocytes
Opsonization:
increasing phagocyte efficiency
Stimulation of inflammation
Prevention of bacterial and viral adhesion
146. KEY CONCEPT Antibody-mediated immunity involves the production of specific antibodies by plasma cells derived from activated B cells
B cell activation usually involves:
antigen recognition, through binding to surface antibodies, costimulation by a Th cell
Antibodies produced by active plasma cells bind to target antigen and:
inhibit its activity or destroy it
remove it from solution
promote its phagocytosis by other defense cells
147. Primary and Secondary Responses Occur in both cell-mediated and antibody-mediated immunity
148. Primary and Secondary Responses to Antigen Exposure First exposure:
produces initial response (Primary)
Next exposure:
triggers secondary response
more extensive and prolonged
memory cells already primed
149. The Primary Response Takes time to develop
Antigens activate B cells
Plasma cells differentiate
Antibody titer slowly rises
Peak response:
can take 2 weeks to develop
declines rapidly
IgM:
is produced faster than IgG
is less effective
150. The Secondary Response Activates memory B cells:
at lower antigen concentrations than original B cells
secrete antibodies in massive qualities
Effects of Memory B Cell Activation
IgG:
rises very high and very quickly
can remain elevated for extended time
IgM:
production is also quicker
slightly extended
151. KEY CONCEPT Immunization produces a primary response to a specific antigen under controlled conditions
If the same antigen appears at a later date, it triggers a powerful secondary response that is usually sufficient to prevent infection and disease
152. Summary of the Immune Response Specific and nonspecific defenses
153. Body Responses to Bacterial Infection
154. Combined Immune System Responses
155. Combined Responses to Bacterial Infection Neutrophils and NK cells begin killing bacteria
Cytokines draw phagocytes to area
Antigen presentation activates:
helper T cells
cytotoxic T cells
B cells activate and differentiate
Plasma cells increase antibody levels
156. Combined Responses to Viral Infection Similar to bacterial infection
But cytotoxic T cells and NK cells are activated by contact with virus-infected cells
157. Summary: Cells of the Immune System
158. KEY CONCEPT Viruses replicate inside cells, whereas bacteria may live independently
Antibodies (and administered antibiotics) work outside cells, so are primarily effective against bacteria rather than viruses
Antibiotics cannot fight the common cold or flu
T cells, NK cells, and interferons are the primary defense against viral infection
159. What is the origin, development, activation, and regulation of normal resistance to disease?
160. Immune System Development Fetus can produce immune response or immunological competence:
after exposure to antigen
at about 3–4 months
161. Development of Immunological Competence Fetal thymus cells migrate to tissues that form T cells
Liver and bone marrow produce B cells
4-month fetus produces IgM antibodies
162. Before Birth Maternal IgG antibodies:
pass through placenta
provide passive immunity to fetus
After Birth
Mother’s milk provides IgA antibodies:
while passive immunity is lost
163. Normal Resistance Infant produces IgG antibodies through exposure to antigens
Antibody, B-cell, and T-cell levels slowly rise to adult levels:
about age 12
164. Hormones of the Immune System
165. 6 Groups of Hormonal Cytokines Interleukins
Interferons
Tumor necrosis factors
Chemicals that regulate phagocytic activities
Colony stimulating factors
Miscellaneous cytokines
166. What are the origins of autoimmune disorders, immunodeficiency diseases, and allergies, and what are some examples of each?
167. Immune Disorders Autoimmune disorders- A malfunction of system that recognizes and ignores “normal” antigens
Activated B cells make autoantibodies against body cells
Immunodeficiency disease-
Thyroiditis
Rheumatoid arthritis
Insulin-dependent diabetes mellitus
Allergies -
168. Immunodeficiency Diseases Problems with embryological development of lymphoid tissues:
can result in severe combined immunodeficiency disease (SCID)
Viral infections such as HIV:
can result in AIDS
Immunosuppressive drugs or radiation treatments:
can lead to complete immunological failure
169. Allergies Inappropriate or excessive immune responses to antigens
Allergens:
antigens that trigger allergic reactions
170. 4 Categories of Allergic Reactions Type I:
immediate hypersensitivity
Type II:
cytotoxic reactions
Type III:
immune complex disorders
Type IV:
delayed hypersensitivity
171. Type I Allergy (1) Also called immediate hypersensitivity
A rapid and severe response to the presence of an antigen
Most commonly recognized type of allergy
Includes allergic rhinitis (environmental allergies)
Sensitization leads to:
production of large quantities of IgE antibodies
distributed throughout the body
Second exposure leads to:
massive inflammation of affected tissues
172. Type I Allergy (2) Severity of reaction depends on:
individual sensitivity
locations involved
Allergens in blood stream may cause anaphylaxis
173. Anaphylaxis Can be fatal
Affects cells throughout body
Changes capillary permeability:
produce swelling (hives) on skin
Smooth muscles of respiratory system contract:
make breathing difficult
Peripheral vasodilatation:
can cause circulatory collapse (anaphylactic shock)
174. Antihistamine Drugs Block histamine released by MAST cells
Can relive mild symptoms of immediate hypersensitivity
175. Stress and the Immune Response Glucocorticoids:
secreted to limit immune response
long-term secretion (chronic stress):
inhibits immune response
lowers resistance to disease
176. Functions of Glucocorticoids Depression of the inflammatory response
Reduction in abundance and activity of phagocytes
Inhibition of interleukin secretion
177. Aging and the Immune Response Immune system deteriorates with age, increasing vulnerability to infections and cancer
178. 4 Effects of Aging on Immune Response Thymic hormone production:
greatly reduced
T cells:
become less responsive to antigens
Fewer T cells reduce responsiveness of B cells
Immune surveillance against tumor cells declines
179. Integration with Other Systems
180. Disorders of the Lymphatic System 3 categories affect immune response:
disorders resulting from:
an insufficient immune response
an inappropriate immune response
an excessive immune response
181. SUMMARY (1) Divisions of the lymphatic system:
lymphatic vessels (lymphatics)
lymph
lymphoid tissues and organs
Types of lymphocytes:
T cells
B cells
NK cells
Lymphoid tissues and organs:
Nodules nodes
MALT thymus
spleen
182. SUMMARY (2) 7 nonspecific defenses:
physical barriers
phagocytes
immunological surveillance
interferons
complement
inflammation
fever
183. SUMMARY (3) Specific defenses:
cell-mediated immunity
antibody mediated immunity
Forms of immunity:
innate or acquired
active or passive
Properties of immunity:
specificity, versatility, memory, andtolerance
184. SUMMARY (4) T cells and cell-mediated immunity:
antigen presentation
MHCs and APCs
antigen recognition
CD8 T cell activation
CD4 T cell activation
185. SUMMARY (5) B cells and antibody-mediated immunity:
sensitization
plasma cells and memory B cells
antibody structure
antigen–antibody complex
5 classes of immunoglobins
186. SUMMARY (6) Primary and secondary responses to antigen exposure
Hormones and the immune system:
interleukins, interferons, TNFs, and CSFs
Immune disorders
Effects of aging on the immune response