Transcript PPT - kimscience.com

IMMUNE SYSTEM AND
DISEASE
INNATE AND ADAPTIVE IMMUNITY
MECHANISMS OF PATHOGENICITY
• Pathogenicity: The ability to cause
• disease
• Virulence: The extent of pathogenicity
PORTALS OF ENTRY
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•
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Mucous membranes
Skin
Blood
Respiratory tract
Gastrointestinal tract
MECHANISMS OF PATHOGENICITY
Figure 15.9
THE CONCEPT OF IMMUNITY
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•
•
•
Susceptibility: Lack of resistance to a disease
Immunity: Ability to ward off disease
Innate immunity: Defenses against any pathogen
Adaptive immunity: Immunity, resistance to a specific
pathogen
AN OVERVIEW OF THE BODY’S DEFENSES
• Innate immunity: Defenses against any pathogen
• Adaptive immunity: Induced resistance to a specific
pathogen
Figure 16.1
FIRST LINE OF DEFENSE
INNATE (NON -SPECIFIC) IMMUNITY
PHYSICAL
FACTORS
• Skin
• Epidermis consists of
tightly packed cells
with
• Keratin, a protective
waterproof protein
• Mucous membranes
• Mucus: Traps microbes
• Ciliary escalator:
Microbes trapped in
mucus are transported
away from the lungs
Figure 16.2
CILIARY ESCALATOR
Figure 16.4
CILIARY ESCALATOR
Figure 24.7
PHYSICAL/CHEMICAL FACTORS
• Lacrimal apparatus:
Washes eye
• Saliva: Washes
microbes off
• Urine: Flows out
• Vaginal secretions:
Flow out
CHEMICAL FACTORS
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•
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Fungistatic fatty acid in sebum
Low pH (3–5) of skin
Lysozyme in perspiration, tears, saliva, and urine
Low pH (1.2–3.0) of gastric juice
Low pH (3–5) of vaginal secretions
GENETIC RESISTANCE
• Some individuals may have enough of a genetic
difference that will allow them to be immune to a
specific pathogen.
• Ex: Humans carrying a gene for sickle-cell anemia are
immune to malaria!
• Other examples: leprosy, tuberculosis (20% exposed are
resistant), certain fungal infections
• Asymptomatic carriers – Herpes simplex
SECOND LINE OF DEFENSE
INNATE (MAINLY NON -SPECIFIC)
FORMED ELEMENTS IN BLOOD
FUNCTION
Red Blood Cells
Transport O2 and CO2
White Blood Cells:
Neutrophils
Phagocytosis
Basophiles
Histamine
Eosinophils
Kill parasites
CELL MORPHOLOGY
FORMED ELEMENTS IN BLOOD
FUNCTION
Monocytes
Phagocytosis
Dendritic cells
Phagocytosis
Natural killer cells
Destroy target cells
CELL MORPHOLOGY
FORMED ELEMENTS IN BLOOD
FUNCTION
T cells
Cell-mediated immunity
B cells
Produce antibodies
Platelets
Blood clotting
CELL MORPHOLOGY
DIFFERENTIAL WHITE CELL COUNT
• Percentage of each type of white cell in a sample of
100 white blood cells
Neutrophils
60–70%
Basophils
0.5–1%
Eosinophils
2–4%
Monocytes
3–8%
Lymphocytes (T and B cells)
20–25%
DEVELOPMENT OF A MACROPHAGE
PHAGOCYTOSIS
• Phago: From Greek,
meaning eat
• Cyte: From Greek,
meaning cell
• Ingestion of microbes
or particles by a cell,
performed by
phagocytes
• Neutrophils
• Fixed macrophages
• Wandering macrophages
VIDEO
Figure 16.6
PHAGOCYTOSIS
Figure 16.7
HOW DO WBC SURVEY AND
RECOGNIZE?
• PRRs – Patten Recognition Receptors
• Protein located on surface of WBC
• PAMPs – Pathogen Associated Molecular Pattern
• Proteins, lipids, or carbs located on the pathogen that are
distinguishable from other non-pathogenic cells such as:
• Peptidoglycan, lipoteichoic acid, lipopolysaccharides, flagellin,
zymosan, double stranded RNA, etc…
• Adherence
COMPONENTS OF LYMPHATIC SYSTEM
Figure 16.5a
MAJOR FUNCTIONS OF LYMPHATIC
SYSTEM
• 1. Provide a route for the extracellular fluid to return
back to the circulatory system
• 2. Acts a “drain off system” for inflammatory system
• 3. Involved in immune response by transporting
numerous WBC (esp. T & B cell, and antibodies)
Imp differences from circulatory system:
Lymph fluid travels only in ONE DIRECTION (extremities to heart)
 Lymph is moved only by contraction of the skeletal muscles
THE LYMPHATIC SYSTEM
Figure 16.5b–c
INFLAMMATION
Identifiable signs of inflammation:
• Redness (rubor)
• Swelling (tumor)
• Pain (dolor)
• Warmth (calor)
• Acute-phase proteins activated (complement,
cytokine, and kinins)
• Vasodilation (histamine, prostaglandins, and
leukotrienes)
WHAT CAUSES AN INFLAMMATORY
RESPONSE?
• Tissue injury or death (physical – bump, fall, etc..)
• Trauma from infection
• Allergic reactions (diet or environmental factors)
PRIMARY FUNCTION OF THE
INFLAMMATORY RESPONSE
• 1. mobilize and attract immune response to site of
injury
• 2. sets scene to repair tissue damage & clear away
harmful substances
• 3. destroy and block microbes from further invasion
THE PROCESS OF INFLAMMATION
Figure 16.8a, b
PHAGOCYTE MIGRATION AND
PHAGOCYTOSIS
[Insert Animation Inflammation: Overview, Steps.]
Figure 16.8c
FEVER
• Hypothalamus normally set at 37°C
• Toxins from bacteria trigger the deregulation of the
hypothalamus (exogenous pyrogen). Examples are
endotoxins (remember them?).
• Pyrogen – substance that causes a rise in body temp
• Monocytes, neutrophils, and macrophages 
endogenous pyrogens as part of inflammatory
response. (ex: macrophages -> interleukin 1 (IL-1) &
tumor necrosis factor (TNF)).
• Vasodilation and sweating: Body temperature falls
FEVER
• Advantages
• Inhibits multiplication of
temp sensitive microbes
• Lower iron concentrations
(nutrient used by some
microbes that can limit their
growth)
• Speeds up immune
response such as
phagocytosis
• Produces Interferons
• Disadvantages
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•
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Tachycardia
Acidosis
Dehydration
44–46°C fatal
INTERFERONS (IFNS)
• IFN- and IFN-: Cause cells to produce antiviral
proteins that inhibit viral replication
• Gamma IFN: Causes neutrophils and macrophages
to phagocytize bacteria
ANTIVIRAL ACTIONS OF INTERFERONS
Figure 16.15
IMMUNE CELL TYPES (AGAIN…)
Good site for review (click here)