BIOL40C Ch. 22 Lymphatic System & Immunity

type of resistance that involves activation of specific lymphocytes that combat a foreign substance

the ability to ward off the pathogens that produce disease

lack of resistance

body system that carries out immune responses

general defense mechanisms effective on a wide range of pathogens

ability to fight a specific pathogen

• 1) cell-mediated immunity
• 2) antibody-mediated immunity

fluid flowing within lymphatic vessels

bone marrow

• 1) draining excess interstitial fluid/plasma proteins from tissue spaces
• 2) transporting dietary lipids/vitamins from GI tract to blood
• 3) facilitating immune responses (recognize foreign substances)

• 1) red bone marrow
• 2) thymus
• 3) spleen
• 4) lymph nodes

• 1) tonsils
• 2) adenoids
• 3) MALT

• 1) larger in diameter
• 2) one-way structure (interstitial fluid can flow in, but not out)
• 3) overlapping endothelial cells

• lymphatic capillary in the villus of the small intestine;
• functions to transport fats from small intestine into blood

• 1) thoracic duct
• 2) right lymphatic duct

• 1) left side of the head, neck, and chest
• 2) left upper extremity
• 3) entire body below ribs

upper right side of the body

mediastinum

• 1) T lymphocytes
• 2) macrophages

• 1) reticular epithelial cells (produce thymic hormones)
• 2) Hassall's corpuscles (T cell death site)

clusters of concentric layers of epithelial cells in the thymic medulla that are the possible site of T cell death

location of T cell maturation

• larger in infants (70g vs. 3g)
• before atrophy, populates secondary lymphatic organs/tissues with T cells

• bean shaped
• dense connective tissue capsule extends into node
• supporting network of reticular fibers & fibroblasts internal to capsule

• filters lymph
• foreign substances trapped by reticular fibers

functioning part of lymph node

lymphatic tissue (lymphocytes, macrophages) around branches of splenic artery

venous sinuses filled with blood and splenic cords (RBCs, macrophages, lymphocytes, plasma cells, granulocytes)

• 1) white pulp
• 2) red pulp

red pulp is involved in the production of blood cells during this time

capsular extensions that divide the lymph nodes into compartments, and provide support and a route for blood vessels into the interior of a node

throughout connective tissue of mucous membranes (no capsule)

ring at top of throat

cecum

spread of disease from one part of the body to another

cancer cells travel via blood/lymphatic system and establish new tumors where they lodge

• 1) skin closely packed
• 2) mucous membranes trap/move microbes
• 3) washing action of tears, urine, saliva

• 1) sebum inhibits growth
• 2) perspiration lysozymes
• 3) acidic pH of gastric juice, vaginal secretions

• 1) interferons
• 2) complement
• 3) defensins

• interferons;
• induce synthesis of antiviral proteins that interfere with viral replication

• enhance certain immune reactions
• cause cytolysis of microbes, promotes phagocytosis, and contributes to inflammation

• kill microbes and tumor cells
• attack cells displaying abnormal MHC antigens

• 1) neutrophils
• 2) macrophages

• 1) chemotaxis
• 2) adherence
• 3) ingestion
• 4) digestion
• 5) killing

• 1) capsule formation
• 2) toxin production
• 3) interference with lysozyme secretion
• 4) ability to counter oxidants produced by phagocytes

• 1) trap foreign material
• 2) begin tissue repair

• 1) redness
• 2) heat
• 3) swelling
• 4) pain
• (5) loss of function

• 1) vasodilation/increased permeability of blood vessels
• 2) phagocyte migration
• 3) tissue repair

accumulation of pus in a confined space

open sore

• abnormally high T that occurs because the hypothalamic thermostat is reset
• intensifies effects of interferons, inhibits bacterial growth, speeds up tissue repair

IL-1 (interleukin 1)

recognition of self & non-self

2nd encounter produces more vigorous response

substances recognized as foreign by the immune responses

stem cells in bone marrow

thymus

• fungi
• viruses
• parasites
• cancer
• tissue transplants

bone marrow

bacteria

small part of the antigen that triggers an immune response

• smaller than antigen
• can't trigger immune response unless attached to body protein

• 1) immunogenicity (ability to provoke immune response)
• 2) reactivity (ability to react to cells/Ab's it caused to be formed)

cells have a great diversity of receptors due to genetic recombination

• major histocompatibility complex
• molecules that are unique surface markers on all nucleated cells

built into cell membrane of all cells except RBCs

endogenous antigen by an infected body cell

viruses

only on membrane of APCs (macrophages, B cells, thymus cells)

exogenous antigen by an APC

microbes

help a T cell recognize whether something is foreign

tests similarity of MHC antigens on body cells of different individuals

for tissue typing and IDing biological parents

• 1) macrophages
• 2) B cells
• 3) dendritic cells

small local mediator proteins involved in immune response

mostly secreted by lymphocytes and APCs

costimulates proliferation of T and B cells

activates macrophages, NK cells

cytokine most important in costimulation of proliferation of helper T cells, cytotoxic T cells, and B cells

activates NK cells

strongly stimulates phagocytosis by neutrophils and macrophages

activates NK cells

T cell

• from CD8+ T cells
• recognize foreign antigens combined with MHC-I molecules on surface of infected body cells, some tumor cells, cells of tissue transplant

• from CD4+ T cells
• recognize exogenous antigens associated with MHC-II molecules on the surface of APCs
• costimulates lymphocytes (secretes IL-2)

• don't attack infected body cells
• can quickly proliferate/differentiate into active T cells and more memory T cells if the same ag enters in the future

• 1) receptor binds to foreign part of MHC-I complex (on infected cell)
• 2) costimulation by IL-2 from helper T cell results in proliferation of CD8 cells
• 3) CD8 T cells proliferate/differentiate into Tc cells and memory Tc cells

• 1) inactive helper T cell receptor binds to foreign part of MHC-II (on APC) & becomes activated
• 2) activated cells produce IL-2 (costimulator)
• 3) Th cell proliferates/differentiates into Th cells and memory Th cells

• 1) secretion of granules containing perforin and granulysin
• 2) secretion of lymphotoxin that activates enzymes in the target cell resulting in DNA fragmentation
• 3) secretion of (gamma)interferon stimulates macrophages to phagocytose

immune system finds, recognizes, & destroys cells with tumor antigens

not effective in destroying types of tumors caused by viruses

B cells

in lymph nodes, spleen, Peyer's patches

B cells after they have differentiated into antibody-secreting cells

• 1) antigen on microbe binds to B cell receptors
• 2) antigen is taken into B cell, broken down, and moved to cell membrane
• 3) helper T cells recognize Ag-MHC-II complex & secretes IL-2 to costimulate B cell
• 4) B cell proliferates/differentiates into plasma cells and memory B cells
• 5) plasma cells enter circulation

• 4 polypeptide chains
• -heavy and light chains
• -variable (tips of H&L) and constant portions
• monomer
• Y shaped

IgG, IgA, IgM, IgD, IgE

protects against viruses and bacteria

localized protection of mucous membranes against viruses/bacteria

• activates complement
• causes agglutination and lysis of microbes
• antigen receptors on B cells

ABO antibodies

activation of B cells

• allergic/hypersensitivity reactions
• protection against parasitic worms

clone of plasma cells that recognize just 1 epitope

fusing B cells with tumor cells (hybridoma) and culturing them

• I) anaphylaxis
• II) cytotoxic
• III) immune complex
• IV) cell-mediated

• anaphylaxis
• most common
• interaction of allergens with IgE Abs of mast cells&basophils

• cytotoxic
• reactions by IgG or IgM against blood/tissue cells
• results in complement activation
• incompatible blood

• immune complex
• involve antigens, IgA or IgM, and complement
• most autoimmune diseases

• cell mediated/delayed hypersensitivity
• allergens are taken up by APCs that migrate to lymph and present allergen to T cells
• intracellular bacteria, some allergens (poison ivy)