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Kayla Lay P2 Lymphatic/Immune System - Coggle Diagram
Kayla Lay P2 Lymphatic/Immune System
Artificial vs. Naturally acquired immunity
Active
Naturally aquired
formed in response to actual bacteria or viral infection
Artificially aquired
formed in response to vaccine of dead or attenuated pathogens
Passive
Naturally acquired
antibodies delivered to fetus via placenta or to infant through milk
Artificially acquired
injection of serum, such as gamma globulin
protection immediate but ends when antibodies naturally degrade in body
Passive vs. Active immunity
Passive
occurs when ready-made antibodies are introduced into body
protection ends when antibodies degrade
B cells are not challenged by antigens; immunological memory does not occur
Active
occurs when B cells encounter antigens and produce specific antibodies against
Humoral response and cellular response
Humoral immunity
antibodies, produced by lymphocytes, circulate freely in bodily fluids
bind temporary to target cell
mark for destruction
B lymphocytes against extracellular pathogens and their toxins
Cellular immunity
lymphocytes act against target cell
directly- by killing infected cells
indirectly- by releasing chemicals that enhance inflammatory response; or activating other lymphocytes or macrophages
T lymphocytes against intracellular pathogens
Major functions of Lymphatic and Immune Systems
Immune
provides resistance to disease
Innate (nonspecific) defense system
constitutes first and second lines of defense to stop attacks by pathogens
Adaptive (specific) defense system
third line of defense attacks particular foreign substances (takes longer to react)
eliminates almost any pathogen or abnormal cell in body
both release and recognize many of the same defense molecules
innate defenses do have specific pathway for certain substances
innate repsonses release proteins that alert cells of adaptive system to foreign molecules
Lymphatic
returns fluids leaked from blood vessels back to blood
Lymph: fluid in vessels; circulates ~ 3L interstitial fluid
delivered from trunks into one of two large lymphatic ducts
Lymph nodes: cleanse lymph
Network of lymphatic vessels (lymphatics): elaborate network of drainage vessels
offer one-way system, ensuring lymph flows only toward heart
Lymphatic capillaries present in meninges where they help drain interstitial fluid and CSF
take up larger molecules and particles; increased permeability b/c minivalves
Larger lymphatic vessels
thinner walls w. more internal valves and anastomose more frequently
collecting vessels in skin travel w/ superficial veins, but deep vessels travels w/ arteries
Lymphatic trunks drain large areas of body
lymphoid organs and tissues provide structural basis of immune system by housing phagocytic cells and lymphocytes
Purpose and examples of First, Second, and Third Line of defense
Second: cells and chemicals- inhibits spread of invaders, inflammation, most import. mechanism
Inflammatory response
macrophages, mast cells, WBCs, and inflammatory chems
triggered whenever body tissues are injured
injuries: trauma, heat, irritating chems, or infections by microorganisms
Benfits
disposes of cell debris and pathogens
alerts adaptive immune system
sets the stage for repair
prevents spread of damaging agents
Four cardinal signs of acute inflammation
heat
swelling
redness
pain
Stages of inflammation
Vasodilation and increased vascular permeability
Phagocyte mobilization
Inflammatory chemical release
Inflammatory chemical release
chem are released into ECF by injured tissues or immune cells
ex: histamine released by mast cells; key inflammatory chem
other inflammatory mediators besides histamine
ex: kinins, prostaglandins, cytokines, and if pathogens involved, complement
all cause vasodilation of local arterioles
all make capillaries leaky
many attract phagocytes to area
Antimicrobial proteins
inferior and complement proteins
Natural Killer Cells
attack cells that lack "self" cell-surface receptors
kill by inducing apoptosis in cancer cells and virus-infected cells
nonphagocytic, large granular lymphocytes that police blood and lymph
kill caner and virus-infected cells
secrete potent chemicals that enhance inflammatory response
Fever
Phagocytes
Phagocytes: WBCs that ingest and digest (eat) foreign invaders
Neutrophils: most abundant phagocytes, but die fighting; become phagocytic on exposure to infectious material
Macrophages: develop from monocytes and are chief phagocytic cells; most robust phagocytic cell
Third: attacks particular foreign substances (take longer to react than inncate)
T lymphocytes: cellular immunity
provide defense against intracellular antigens
ex: cells infected w/ viruses or bacteria, cancerous or abnormal cells, foreign (transplanted) cells
some T cells directly kill cells; others release chems that regulate immune response
two population
CD4 cells become helper T cells: activate B cells, other T cells, and macrophages; direct adaptive immune response
CD8 cells become cytotoxic T cells: destroy cells harboring foreign antigens
Antigen presenting cells
do not respond to specific antigen
play essential auxiliary roles in immunity
Dendritic cells, macrophages, B cells
engulf antigens and present fragments of antigens to T cells for recognition
B lymphocytes: humoral immunity
When B cells encounters target antigen, it provokes humoral immune response
antibodies specific for that particular antigen are then produces
First: Surface barriers
Skin and mucous membranes, along w/ their secretions
keratin is resistant to weak acids and bases, bacterial enzymes, and toxins
mucosae provide similar mechanical barriers
physical barrier to most microorganisms
produce productive chem that inhibit or destroy microorganisms
Acid: acidity of skin and some mucous secretions inhibits growth; acid mantle
Enzymes: lysozyme of saliva, respiratory mucus, and lacrimal fluids kills
Mucin: sticky mucus that lines digestive and respiratory tract traps
Respiratory system also has modifications to stop pathogens
mucus-coated-hairs in nose trap inhaled particles
cilia of upper respiratory tract sweep dust-and-bacteria-laden mucus toward mouth
Antigens and antibodies
Antigens
substances that can mobilize adaptive defenses and provoke an immune response
targets of all adaptive immune responses
most are large, complex molecules not normally found in body (nonself)
characteristic
contain antigentic determinants
can be self-antigens
all cells are covered w/ variety of proteins located on surface that are not antigenic to self, but may be antigenic to others in transfusions or grafts
one set of important self-proteins are group of glycoproteins called MHC proteins
coded by genes of MHC and unique to each individual
contain groove that can hold piece of self-antigen or foreign antigen
can be a complete antigen or hapten (incomplete)
Antibodies
capable of binding specifically w/ antigen detected by B cells
grouped into one of five Ig classes
proteins secreted by plasma cells
Basic antibody structure
overall T- or Y-shaped antibody monomer consists of four looping polypeptide chains linked by disulfide bonds
four chains
two identical heavy (H) chains w/ hinge region at "middles"
two identical light (L) chains
variable (V) regions at one end of each arm combine to form two identical antigen-binding sites
stems make up constant (C) regions
Antibody classes
five major classes: IgM, IgA, IgD, IgG, and IgE
Antibody targets and functions
antibodies do not destroy antigens; they inactivate and tag them
form antigen-antibody (immune) complexes
defense mechanisms used by antibodies
Neutralization
antibodies block specific sites on viruses or bacterial exotoxins
prevent antigens from binding to receptors on tissue cells
Agglutination
allows for antigen-antibody complexes to become cross-linked into large lattice-like clumps
Precipitation
soluble molecules are cross-linked into complexes
complexes precipitate out of solution
Complement fixation
when several antibodies are bound close together on same antigen, complement-binding sites on their stem regions align
Location of Lymphatic organs and their functions
Primary
Bone marrow
function
where T and B cells originate; only B cells mature in bone marrow
major hemopoietic tissue; produce all formed elements of blood: RBCs, WBCs, and platelets
location
center of most bones, such as ribs, breast bone, shoulder blades, collarbones, hipbones, skull, and spine
Thymus
location
upper chest behind breastbone; inferior neck
function
where T cells mature
most active and largest in size during childhood
stops growing during adolescence, then gradually atrophies
still produces immunocompetent cells, though more slowly
Secondary
Lymph nodes
location
some are nearer to body surface in inguinal, axillary, cervical, neck, and chest regions of body where collecting vessels converge into trunks
most embedded deep in CT in clusters along lymphatic vessels
function
Cleansing the lymph: act as lymph "filters"
macrophages remove and destroy microorganisms and debris that enters lymph; prevent unwanted substances in blood
Immune system activation: offer place for lymphocytes to become activated and mount an attack against antigens
Spleen
location
left side or abdominal cavity, below stomach
function
cleanses blood and removes aged or defective RBCs
site for lymphocyte activation and proliferation
stores platelets, monocytes, and iron
MALT
Peyer's patches
location
ileum (distal part of small intestine)
function
destroy bacteria, preventing them from breaching intestinal wall
generate "memory" lymphocytes
Appendix
location
lower right of abdomen, in large intestine
function
destroy bacteria, preventing them from breaching intestinal wall
generate "memory" lymphocytes
Tonsils
location
Palatine tonsils: posterior end of oral cavity
Lingual tonsil: lumpy collection of follicles at base of tongue
Pharyngeal tonsil: adenoids; in posterior wall of nasopharynx
Tubal tonsils: surround openings of auditory tubes into pharynx
function
gather and remove pathogens in food and air
tonsillar crypts: bacteria or particulate matters enter, become trapped and destroyed
Cells involved in the immune system and their functions
Innate
Phagocytes: WBCs that ingest and digest foreign invaders
Neutrophil: destroy by ingesting and releasing enzymes
Eosinophil: fight helminthic parasites
Basophil: initiate allergic repsponses
Mast cell: cause inflammation in allergic responses
Dendritic cells: presents antigens to T cells
Macrophage: phagocytic killers; triggers powerful inflammatory responses and recruit additional defenses
Monocyte: inflammatory and anti-inflammatory responses
Natural Killer cells
killer cancer and virus-infected cells before adaptive immune system is activated; induce apoptosis
Adaptive
T cells
provide defense against intracellular antigens
CD4 cells become helper T cells that can activate B cells, other T cells, and macrophages
some become regulatory T cells, moderate immune system
secrete cytokines that recruit other immune cells
induce T and B cell proliferation
can only see antigen on MCH II
CD8 cells become cytotoxic cells that destroy cells harboring foreign antigens
target virus-infected cells, cells w/ intracellular bacteria or parasites, cancer cells, or foreign cells w/ antigen on MCH I
release perforins and granzymes by exocytosis; stimulate apoptosis
binds specific membrane receptor on target cell; stimulate apoptosis
some become memory cells
Cytokines: chemical messengers
IL-1 released by macrophages and stimulates T cells to release and synthesize IL-2 (encourage T cells to divide rapidly)
Regulatory T cell
important in preventing autoimmune reactions
B cells
encounters target antigen and provokes humoral immune response
most clones become plasma cells, secreting antibodies; marking free antigens for destruction
Innate(natural) immune defenses and Adaptive(acquired) immune defenses
Innate (nonspecific) defense system
constitutes first and second line of defense
First line of defense: exteral body membranes (skin and mucosae)
Second line of defense: antimicrobial proteins, phagocytes, and other cells (inhibit spread of invaders; inflammation most import.)
stop attacks by pathogens
Adaptive (specific) defense system
Third line of defense attacks particular foreign substances (takes longer to react than innate)
eliminates almost any pathogen or abnormal cell in body
characteristics
It is systemic: not restricted to initial site
It has memory: mounts an even stronger attack to "known" antigens (second and subsequent exposures)
It is specific: recognizes and targets specific antigens
two main branches
Cellular (cell-mediated) immunity
Humoral (antibody-mediated) immunity
Disorders associated with the Immune system
Pus
creamy yellow mixture of dead neutrophils, tissue/cells, and living/dead pathogens
Abscess: collagen fibers are laid down, walling off sac of pus; may need to be surgically drained
some bacteria, such as tuberculosis bacilli, resist digestion by macrophages and remain alive inside
bacteria may remain inactive forever, or if immunity decreases, may break free, become activated, and cause disease
can form tumorlike growths called granulomas
Immunodeficiency
congenial or acquired conditions that causes cancer of B cells, which depress lymph node cells
Acquired immune deficiency syndrome
Human immunodeficiency virus cripples immune system by interfering w/ activity of helper T cells
severe weight loss, nigh sweats, and swollen lymph nodes
opportunistic infections occur, pneumocystis pneumonia and kaposi's sarcoma
HIV transmitted via bodily fluids: blood, semen, and vaginal secretions
HIV enter body via: blood transfusions; blood-contaminated needles; sexual intercourse and oral sex; mother to fetus
HIV destroys helper T cells, depress cellular immunity
symptoms: immune system collapse
no cure for AIDS
Severe combined immunodeficiency syndrome: genetic defect w/ marked deficit in B and T cells
ADA enzyme allows accumulation of metabolites lethal to T cells; fatal if untreated
treatment: bone marrow transplant
Hodgkin's disease: an acquired immunodeficiency that causes cancer of B cells, which depress lymph node cells
Autoimmune disease
results when immune system loses ability to distinguish self from foreign
Autoimmunity: production of autoantobodies and sensitized Cytototoxic T cells that destroy body tissues
treatment
suppress entire immune system
anti-inflammatory drugs, such as corticosteroids
blocking cytokine action
blcoking co-stimulatory molecules
research
activating regulatory T cells; inducing self tolerance using vaccines; directing antibodies against self-reactive immune cells
Hypersensitivities
immune responses to perceived (otherwise harmless) threat that cause tissue damage
Immediate
activated IgE against antigen bind to mast cells and basophils
later encounter w/ same allergen causes flood to histamine release from IgEs, resulting in induced inflammatory response
histamines causes vasodilation and leakiness of vessels
allergic reactions local or systemic
systemic
anaphylactic shock
usually seen w/ injected allergen (ex. bee sting)
bronchioles constrict, making breathing difficult
vasodilation results in low blood volume, cam cause circulatory collapse
treatment: epinephrine
Acute (type I) hypersensitivities (allergies); antigen that causes allergic reaction begins in secs. after contact w/ allergen