The Immune

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The Immune Lymphatic System, Ch.22

• Types of Defense
• ________________________ Innate defenses
• Present at birth and provide immediate protection
• 1st line of defense skin and mucous membranes
• 2nd line of defense internal defenses
• ________________________ Immunity
• ______________
• ______________

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Nonspecific Defense Mechanisms

• Physical barriers
• Chemical barriers
• Increase in body temperature
• Production of antimicrobial proteins
• Inflammatory response

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First line skin mucous membranes

• Physical and chemical barriers
• Epidermis
• Skin barrier, when sheds will remove microbes
• Invade adjacent tissues circulation thru cuts
• Mucus- traps microbes
• Hair, cilia
• Lacrimal apparatus- tears contain lysozyme
• Lysozyme found in tears, perspiration, nasal
  secretions, tissue fluids
• Urine, vaginal secretions, defecation, vomit
• Acidic sebum, perspiration, gastric juice,
  vaginal secretions

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Second line Internal defenses

• Antimicrobial proteins
• Interferons (IFN)- virus infected cells produce
  anti-viral proteins, communicate to uninfected
  cells
• Complement system- enhance immune, cytolysis,
  phagocytosis, inflammation
• Transferrins- inhibit bacterial growth
• Natural Killer Cells phagocytes
• Inflammation
• Fever
• ? temp due to reset hypothalamic thermostat
• Intensifies IFN, microbes, speed up repair

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Natural Killer Cells

• NKC 5-10 of lymphocytes in blood
• Spleen, lymph nodes, RBM
• Lack molecules to identify T B cells
• Ability to kill variety of infected tumor cells
• Attack cell w/abnormal MHC
• Bind
• Release granules of toxic substance
• Perforin ? cytolysis
• Granzymes induce apoptosis or self-destruction
• Kills cell but NOT MICROBES inside cell
• Microbes need to be phagocytized

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Phagocytes

• Phagocytosis (part of Specific Immunity)
• Neutrophils
• __________________ ? wandering macrophages
• Fixed macrophages stay put
• Histiocytes, Kupffer cells, alveolar, microglia,
  and tissue macrophages in spleen, lymph nodes,
  RBM
• 5 phases
• _________________
• Adherence
• Ingestion
• Digestion
• Killing

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Inflammatory response fig 22.10

• Causes pathogens (bacteria, virus), abrasions,
  chemical irritations, disturbances of cells,
  extreme temperatures, burns, radiation
• 4 signs symptoms
• ______________
• ______________
• ______________
• ______________
• Can also cause loss of function depending upon
  site and extent of injury

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Inflammatory response (2)

• Purpose attempt to dispose of microbes, toxins,
  foreign substances
• Prevents spread of above
• Prepare for repair and restoration
• 3 Stages of inflammation
• Vasodilation ? bv permeability
• Emigration of phagocytes
• Tissue repair

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Vasodilation ? permeability

• Vasodilation ? ? blood flow to area
• Remove microbial toxins, dead cells
• ? permeability ? proteins clotting factors
• Substances responsible
• Histamine
• Kinins
• Prostaglandins
• Leukotrienes
• Complement

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1. When a localized area exhibits increased
capillary filtration and swelling, this is an
indication that

• A. an immune response is underway
• B. fever is developing
• C. inflammation is occurring
• D. Ab are phagocytizing target cells
• E. fever is ending

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2. Which type of molecule is produced by
viral-infected cells to communicate to
non-infected cells of the presence of a virus?

• A. Complement
• B. Interferon
• C. Pyrogen
• D. Antigen
• E. Antibodies

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3. Saliva and tears contain this enzyme that
destroys bacteria.

• A. Trypsin
• B. Amylase
• C. Lysozyme
• D. Salivase
• E. Kinase

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Specific resistance Immunity

• Specificity and memory
• Humoral or antibody-mediated (AMI)
• _________________ into plasma cells ? synthesize
  ___________ or immunoglobulins
• Antibody bind and inactivates its antigen
• Cell- mediated (CMI)
• _______________ proliferate into cytotoxic T
  cells that ______________ the invading antigen

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T cell populations

• Cytotoxic T cells
• Kill infected cells and cancer cells
• Helper T cells
• Secrete __________________- help regulate B cells
  and T cells, ? play a pivotal role in BOTH
  humoral cell mediated responses
• Secrete protein factors and molecules secreted to
  regulate neighboring cells
• Memory T cells
• Remain from proliferated clone after CM response

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Cell mediated immunity

• Activation of T cells by specific antigen
• T cell proliferation differentiation into clone
  of effector cells
• Elimination ________________ ? cytolysis
• Specific to specific antigens
• Can leave lymph tissue to seek and destroy
  foreign antigens

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Antibody-mediated response

• _______________________
• ________ responds to _____________ antigen
• Stay in lymph tissue nodes,spleen,MALT
• Activated upon presence of foreign antigen
• Differentiate into plasma cells
• Produce antibodies
• Ab circulate in lymph and blood to reach invasion
  site
• Some B cells become ____________________

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Ab-mediated response

• Inactive B cell receptor binds antigen, can
  stimulate T cell to intensify response
• Plasma cells develop and produce Ab
• Memory cells develop and remain to respond to
  antigen in the future

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Production of antibodies
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4. A "foreign" molecule which can invoke the
immune response is called a(n)

• A. Antigen
• B. Immunoglobulin
• C. Hapten
• D. Antibody
• E. Histamine

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5. The immune cell that allows for subsequent
recognition of an antigen resulting in a
secondary response is called a(n)

• A. helper T-cell
• B. memory cell
• C. antigen-presenting cell
• D. plasma cell
• E. macrophage

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6. Active, artificially acquired immunity is a
result of

• A. Vaccination
• B. Ab passed from mother to fetus through the
  placenta
• C. Ab passed from mother to baby through breast
  milk
• D. injection of immune serum
• E. Ab produced due to previous exposure to an
  antigen

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Clinical Connections

• Organ transplants- rejection dependent upon
  similarity of MHCs
• Immunodeficiency- as in HIV, lose helper T cells,
  opportunistic infections may occur
• Autoimmune diseases- fail to display self
  tolerance and attack own tissues
• Hypersensitivity- allergic rxn to things that
  most people tolerate (4 types)

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7. Cytotoxic T cells kill target cells

• A. through insertion of perforins into the
  target's membrane
• B. by secreting antibodies
• C. by phagocytosis
• D. through injection of tumor necrosis factor
• E. Causing an inflammatory response

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8. Lymphocytes that develop immunocompetence in
the thymus are

• A. neutrophils
• B. T lymphocytes
• C. B lymphocytes
• D. Basophils
• E. Eosinophils

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9. This type of disease results from the
inability of the immune system to distinguish
self from non-self antigens

• A. Allergy
• B. Immunodeficiency
• C. Anaphylaxis
• D. Autoimmune disease
• E. Inflammatory response

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The Lymphatic System

• Vessels
• Primary lymphatic organs
• Red bone marrow
• Thymus
• Secondary lymph organs and tissue
• Lymph nodes
• Spleen
• Lymph nodules (tissue because lacks capsule)

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Functions of the Lymphatic System

• Draining excess interstitial fluid
• ______________ interstitial fluid that has
  passed into a lymph vessel
• Transporting dietary lipids
• Lacteals-- GI tract to blood
• Protecting against invasion through immune
  responses
• Lymphatic tissue specialized reticular CT with
  many lymphocytes

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Lymphatic vessels, fig 22.2
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Lymphatic vessels

• Begin as lymph capillaries
• Spaces between cells, closed one end
• Unite to form larger vessels
• Lymph vessels resemble veins but
• Are thinner
• Have more valves
• Intervals along vessels lymph nodes w/masses of
  T cells B cells

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Lymphatic vessels (2)

• In skin lie in subQ, follow same general route
  as veins
• Viscera generally follow arteries forming
  plexuses around them
• Avascular tissue often lack lymphatic
  capillaries
• Cartilage, epidermis, cornea, CNS, spleen, RBM

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Lymph capillaries

• Slightly larger than blood capillaries
• have a unique structure interstitial fluid can
  flow in but not out
• endothelial cells in wall overlap BUT
• when pressure is greater in interstitial fluid
  than in lymph, cells separate slightly
• one-way valve opening, fluid enters
• when pressure greater capillary, closed lymph
  cannot flow out

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Lymph capillaries (2)

• Anchoring filaments- contain elastic fibers,
  attach lymphatic endothelial cells to surrounding
  tissues
• When excess interstitial fluid accumulates,
  tissue swells? filaments are pulled, opening
  larger for fluid to enter
• Lacteals- specialized lymph capillaries in small
  intestine
• Carry dietary lipids lymph vessels?blood
• Chlye- lipids present in lymph

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Lymph formation and flow

• Most components of plasma can filter freely to
  form interstitial fluid
• More out than back in ? lymph returns this fluid
• Excess filtered fluid 3L/daylymph
• Small amt of proteins (most plasma proteins too
  large)
• Proteins dont easily diffuse back?lymph
  important
• Valves for one way movement
• Skeletal and respiratory pumps (as veins)

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Lymph nodes

• 600 scattered throughout body
• superficial and deep, usually in groups
• however, high concentration in
• Mammary gland
• Axillae
• Groin
• Function as filters
• Foreign substances trapped by reticular fibers
  within sinuses
• Macrophages destroy by phagocytosis
• Lymphocytes destroy by immune responses

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Flow thru nodes is unidirectional

• Afferent lymphatic vessels ?
• valves of node ?
• subcapsular sinus ?
• trabecular sinuses (cortex) ?
• medullary sinuses ?
• one of 2 efferent lymph vessels ?
• valves ?
• hilum also where bv enter and leave

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Primary (1) lymphatic organs

• Where stem cells divide become immunocompetent
• Red Bone Marrow
• Thymus
• Stem cells divide mature into
• B cells red bone marrow
• T cells - thymus

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2 Lymphatic organs and tissue

• Where most immune responses occur
• Lymph nodes
• Spleen
• Lymphatic nodules
• MALT mucosa associated lymphatic tissue in
  mucous membrane GI, urinary, repro tracts and
  respiratory airways
• GALT- gut associated lymphoid tissue
• Tonsils
• Peyers patches

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Spleen is a lymphatic organ, fig 22.7

• Largest single mass of lymphatic tissue
• In fetus develops blood cells
• Phagocytosis of worn out blood cells
• 2 types of tissue
• white pulp- mostly lymphatic tissue
• Macrophages lymphocytes arranged around
  branches of splenic artery
• red pulp consists of venous sinuses filled with
  blood cords of splenic tissue
• RBC, macrophages, lymphocytes, plasma cells,
  granulocytes

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Functions of the red pulp of spleen

• ______________ by macrophages of ruptured, worn
  out, or defective red blood cells and platelets
• _______________________ (up to 1/3 of bodys
  supply)
• _____________________ during fetal life

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