anatomy & physiology chapter 12 the lymphatic system and body defenses
TRANSCRIPT
Warm-up 05/18Warm-up 05/18
What are the active and passive examples of naturally acquired immunity?
What are the active and passive examples of artificially acquired immunity?
Agenda 05/18Agenda 05/18
• Finish Humoral Immune Response– Antibodies, Immunoglobulin types, functions
• Cellular (Cell-Mediated) Immune Response– T-Cells
• Operation Antibody p.28
Monoclonal AntibodiesMonoclonal Antibodies
Antibodies prepared for clinical testing or diagnostic services
Produced from descendents of a single cell line
Examples of uses for monoclonal antibodies Diagnosis of pregnancy
Treatment after exposure to hepatitis and rabies
Antibodies (Immunoglobulins) (Igs)Antibodies (Immunoglobulins) (Igs)
Soluble proteins secreted by B cells (plasma cells)
Carried in blood plasma
Capable of binding specifically to an antigen
Antibody StructureAntibody Structure
Four amino acid chains linked by disulfide bonds
Two identical amino acid chains are linked to form a heavy chain
Antibody StructureAntibody Structure
The other two identical chains are light chains
Specific antigen-binding sites are present
Antibody ClassesAntibody Classes
Antibodies of each class have slightly different roles
Five major immunoglobulin classes IgM – can fix complement
IgA – found mainly in mucus
IgD – important in activation of B cell
IgG – can cross the placental barrier
IgE – involved in allergies
Antibody FunctionAntibody Function
Antibodies inactivate antigens in a number of ways
Complement fixation
Neutralization
Agglutination
Precipitation
Cellular (Cell-Mediated) Immune Cellular (Cell-Mediated) Immune ResponseResponse
Antigens must be presented by macrophages to an immunocompetent T cell (antigen presentation)
T cells must recognize nonself and self (double recognition)
After antigen binding, clones form as with B cells, but different classes of cells are produced
T Cell ClonesT Cell Clones
Cytotoxic T cells
Specialize in killing infected cells
Insert a toxic chemical (perforin)
Helper T cells
Recruit other cells to fight the invaders
Interact directly with B cells
T Cell ClonesT Cell Clones
Suppressor T cells
Release chemicals to suppress the activity of T and B cells
Stop the immune response to prevent uncontrolled activity
A few members of each clone are memory cells
Operation Antibody p.28
• In your small groups:– Follow directions for your assigned case.– Write a script and be ready to perform for the
class tomorrow.– EXTRA CREDIT: RECORD YOUR SKIT ON A FLIP
CAMERA (in the form of a movie)
• Homework– Packet pps. 3-4, 8-19 Due Thursday– Packet pps. 20-22 Due Friday
Agenda 05/16Agenda 05/16
• First and Second Lines of Defense
• Intro to Chapter 12 Independent Project– Due Monday May 30th
• Miracle of the Immune System
Body DefensesBody Defenses
The body is constantly in contact with bacteria, fungi, and viruses
The body has two defense systems for foreign materials
Nonspecific defense system
Specific defense system
Also known as the immune system
Nonspecific Body DefensesNonspecific Body Defenses
Body surface coverings
Intact skin
Mucous membranes
Specialized human cells
Chemicals produced by the body
Surface Membrane Barriers – Surface Membrane Barriers – First Line of DefenseFirst Line of Defense
The skin
Physical barrier to foreign materials
pH of the skin is acidic to inhibit bacterial growth
Surface Membrane Barriers – Surface Membrane Barriers – First Line of DefenseFirst Line of Defense
Stomach mucosa
Secretes hydrochloric acid
Has protein-digesting enzymes
Saliva and lacrimal fluid contain lysozyme
Mucus traps microogranisms in digestive and respiratory pathways
Defensive CellsDefensive Cells
Phagocytes (neutrophils and macrophages)
Engulfs foreign material into a vacuole
Enzymes from lysosomes digest the material
Defensive CellsDefensive Cells
Natural killer cells
Can lyse and kill cancer cells
Can destroy virus- infected cells
Inflammatory Response - Inflammatory Response - Second Line of DefenseSecond Line of Defense Triggered when body tissues are injured
Produces four cardinal signs Redness Heat Swelling Pain
Results in a chain of events leading to protection and healing
Functions of the Inflammatory Functions of the Inflammatory ResponseResponse
Prevents spread of damaging agents
Disposes of cell debris and pathogens
Sets the stage for repair
Antimicrobial ChemicalsAntimicrobial Chemicals
Complement Activated when
they encounter and attach to cells (complement fixation)
Damage foreign cell surfaces
Antimicrobial ChemicalsAntimicrobial Chemicals
Interferon
Secreted proteins of virus-infected cells
Bind to healthy cell surfaces to inhibit viruses binding
FeverFever
Abnormally high body temperature
Hypothalmus heat regulation can be reset by pyrogens (secreted by white blood cells)
High temperatures inhibit the release of iron and zinc from liver and spleen needed by bacteria
Fever also increases the speed of tissue repair
• What are the four symptoms produced by the healing process?
1.Redness 2.Heat3.Pain4.Swelling
Warm-up 05/17Warm-up 05/17
• Third Line of Defense – THE IMMUNE SYSTEM– Humoral immunity– Cellular immunity
• Classwork/Homework Due Thursday– Packet pps. 3-4, 8-19
Agenda 05/17Agenda 05/17
Specific Defense: The Immune Specific Defense: The Immune System – Third Line of DefenseSystem – Third Line of Defense
Antigen specific – recognizes and acts against particular foreign substances
Systemic – not restricted to the initial infection site
Has memory – recognizes and mounts a stronger attack on previously encountered pathogens
Types of ImmunityTypes of Immunity
Humoral immunity
Antibody-mediated immunity
Cells produce chemicals for defense
Cellular immunity
Cell-mediated immunity
Cells target virus infected cells
Antigens (Nonself)Antigens (Nonself) Any substance capable of exciting the
immune system and provoking an immune response
Examples of common antigens Foreign proteins
Nucleic acids
Large carbohydrates
Some lipids
Pollen grains
Microorganisms
Self-AntigensSelf-Antigens
Human cells have many surface proteins
Our immune cells do not attack our own proteins
Our cells in another person’s body can trigger an immune response because they are foreign
Restricts donors for transplants
AllergiesAllergies
Many small molecules (called haptens or incomplete antigens) are not antigenic, but link up with our own proteins
The immune system may recognize and respond to a protein-hapten combination
The immune response is harmful rather than protective because it attacks our own cells
Cells of the Immune SystemCells of the Immune System
Lymphocytes Originate from hemocytoblasts in the red bone
marrow
B lymphocytes become immunocompetent in the bone marrow
T lymphocytes become immunocompetent in the thymus
Macrophages Arise from monocytes
Become widely distributed in lymphoid organs
Humoral (Antibody-Mediated) Humoral (Antibody-Mediated) Immune ResponseImmune Response
B lymphocytes with specific receptors bind to a specific antigen
The binding event activates the lymphocyte to undergo clonal selection
A large number of clones are produced (primary humoral response)
Humoral (Antibody Mediated) Humoral (Antibody Mediated) Immune ResponseImmune Response
Most B cells become plasma cells
Produce antibodies to destroy antigens
Activity lasts for four or five days
Some B cells become long-lived memory cells (secondary humoral response)
Secondary ResponseSecondary Response
Memory cells are long-lived
A second exposure causes a rapid response
The secondary response is stronger and longer lasting
Active ImmunityActive Immunity
Your B cells encounter antigens and produce antibodies
Active immunity can be naturally or artificially acquired
Passive ImmunityPassive Immunity
Antibodies are obtained from someone else Conferred naturally from a mother to her
fetus
Conferred artificially from immune serum or gamma globulin
Immunological memory does not occur
Protection provided by “borrowed antibodies”
Immunoglobulin Classes
I. IgGo Structure: Monomero Percentage serum antibodies: 80%o Location: Blood, lymph, intestineo Half-life in serum: 23 dayso Complement Fixation: Yeso Placental Transfer: Yeso Known Functions: Enhances phagocytosis,
neutralizes toxins and viruses, protects fetus and newborn.
Immunoglobulin Classes
II. IgMo Structure: Pentamero Percentage serum antibodies: 5-10%o Location: Blood, lymph, B cell surface (monomer)o Half-life in serum: 5 dayso Complement Fixation: Yeso Placental Transfer: Noo Known Functions: First antibodies produced during
an infection. Effective against microbes and agglutinating antigens.
Immunoglobulin Classes
III. IgAo Structure: Dimero Percentage serum antibodies: 10-15%o Location: Secretions (tears, saliva, intestine, milk),
blood and lymph.o Half-life in serum: 6 dayso Complement Fixation: Noo Placental Transfer: Noo Known Functions: Localized protection of mucosal
surfaces. Provides immunity to infant digestive tract.
Immunoglobulin Classes
IV. IgDo Structure: Monomero Percentage serum antibodies: 0.2%o Location: B-cell surface, blood, and lympho Half-life in serum: 3 dayso Complement Fixation: Noo Placental Transfer: Noo Known Functions: In serum function is
unknown. On B cell surface, initiate immune response.
Immunoglobulin Classes
V. IgEo Structure: Monomero Percentage serum antibodies: 0.002%o Location: Bound to mast cells and basophils
throughout body. Blood.o Half-life in serum: 2 dayso Complement Fixation: Noo Placental Transfer: Noo Known Functions: Allergic reactions. Possibly lysis
of worms.
Warm-up 05/19Warm-up 05/19
• What are the three lines of defense against infection that your body has?
• What is involved with each line of defense?• What is the major difference between
humoral and cell mediated responses
Organ Transplants and RejectionOrgan Transplants and Rejection
Major types of grafts
Autografts – tissue transplanted from one site to another on the same person
Isografts – tissue grafts from an identical person (identical twin)
Allografts – tissue taken from an unrelated person
Xenografts – tissue taken from a different animal species
Organ Transplants and RejectionOrgan Transplants and Rejection
Autografts and isografts are ideal donors
Xenografts are never successful
Allografts are more successful with a closer tissue match
Disorders of Immunity: Allergies Disorders of Immunity: Allergies (Hypersensitivity)(Hypersensitivity) Abnormal, vigorous immune responses
Types of allergies
Immediate hypersensitivity
Triggered by release of histamine from IgE binding to mast cells
Reactions begin within seconds of contact with allergen
Anaphylactic shock – dangerous, systemic response
Disorders of Immunity: Allergies Disorders of Immunity: Allergies (Hypersensitivity)(Hypersensitivity)
Types of allergies (continued)
Delayed hypersensitivity
Triggered by the release of lymphokines from activated helper T cells
Symptoms usually appear 1–3 days after contact with antigen
Disorders of Immunity: Disorders of Immunity: ImmunodeficienciesImmunodeficiencies
Production or function of immune cells or complement is abnormal
May be congenital or acquired
Includes AIDS – Acquired Immune Deficiency Syndrome
Disorders of Immunity: Disorders of Immunity:
Autoimmune DiseasesAutoimmune Diseases
The immune system does not distinguish between self and nonself
The body produces antibodies and sensitized T lymphocytes that attack its own tissues
Disorders of Immunity: Disorders of Immunity:
Autoimmune DiseasesAutoimmune Diseases Examples of autoimmune diseases
Multiple sclerosis – white matter of brain and spinal cord are destroyed
Myasthenia gravis – impairs communication between nerves and skeletal muscles
Juvenile diabetes – destroys pancreatic beta cells that produce insulin
Rheumatoid arthritis – destroys joints
Disorders of Immunity: Disorders of Immunity:
Autoimmune DiseasesAutoimmune Diseases
Examples of autoimmune diseases (continued)
Systemic lupus erythematosus (SLE) – affects kidney, heart, lung and skin
Glomerulonephritis – impairment of renal function
Self Tolerance BreakdownSelf Tolerance Breakdown Inefficient lymphocyte programming Appearance of self-proteins in the
circulation that have not been exposed to the immune system Eggs Sperm Eye lens
Cross-reaction of antibodies produced against foreign antigens with self-antigens Rheumatic fever