Please enable JavaScript.
Coggle requires JavaScript to display documents.
Lymphatic and Immune system Santo Celestino Period:5 - Coggle Diagram
Lymphatic and Immune system
Santo Celestino
Period:5
• Major functions of the Lymphatic & Immune systems (include BOTH)
Immune system- the physical and celluar denfense system of a living organism
• Location of Lymphatic organs and their functions
Lymphoid organs and tissues- provide structral basis of immune system by housing phagocytic cells and lymphocytes
NETWORK OF LYMPHATIC VESSLES
LYMPH: FLUID IN VESSELS
LYMPH NODES: CLEANSE LYMPH
Lymphatic SYSTEM
Lymphactic vessles-
drainage vessles
One way pathway to HEART
Larger lymphactic vessels -
lymph capillaries drain into increasingly larger vessels called collecting lymphactic vessles
consist of collecting vessels, trunks, and ducts
have structures and tunics similar to viens, expect
have thinner walls, with more internal valves
anastomose more frequently
Lymphactic capillaries
blind-ended vessles that weace tissue cells and blood capilaties
can take up larger molecules and particles that blood capillaiers connot - proteins, cell debris, pathogens, can cancer cells, can act as route for pathogen or cancer cells to travel throughtout body
Increased premeability due to two specialized structres
endothelial cells overlap lossely to form one-way minivalves
minivalves are anchored by collegen filaments to matrix, so increases in ECF volume opens minivalves even more
Lacteals: specialized lymph capillaries present in intestinal mucoisa- absorb digested fat and deliver fatty lymph (chyle) to the blood
Lymphatic trunk, whick are foremed by union of largest collecting vessles, drain large aread of body
Named for regions of body they drain:
– Paired lumbar
– Paired bronchomediastinal
– Paired subclavian
– Paired jugular trunks
– Single intestinal trunk
Distribution and Structure of Lymphatic Vessels
FROM TRUNKS INTO ONE OF TWO LARGE LYMPHATIC DUCTS
RIGHT LYMPHACTIC DUCT - DRAINS RIGHT UPPER ARM AND RIGHT SIDE OF HEAD AND THORAX
THORACIC DUCT - DRAINS REST OF BODY
Lymph node
Secondary lymphoid organs of body
Functions
Immune system activation: offer a place for lymphocytes to beomce activated and mount an attack against antigens
cleanising the lymph: act as lymph "
filters*
MACROPHAGES
remove and destroy microogranisms and debris that enter lymp
Structure
Lymph nodes
Surrounded by external fibrous capsule
Capsule fibers extend inward as trabeculae that divide node into compartmnt
two regions
Medulla
medullary cords extend inward from cortex and contain B cells, T cells, and Plasma cells
Cortex
superficial area of cortex contains follicles with germinal center that are heavy with dividing B cells
Lymph sinues are found throughout node
consist of large lymphactic capillaries spannd by crisscrossing reticular fibers
macrophages resides on fibers, checking for and phagocytizing any foregin matter
circulation
Lymph enter convex side of node via afferent lymphactic vessles
travels through large subcapsular sinus and then into smaller sinuses found throughout cortex and medulla
lymph then enters
medullary sinuses
finally exists concave side of hilum via efferent lymphatic vessles
** presense of fewer efferent vessles causes flow to somewaht stagnate, allows lymphocytes and macrophages time to function
** lymph travels through several nodes
Lymphoid organs
TWO FUNCTIONAL CATEGORIES
PRIMARY LYMPHOID ORGANS
areas where T and B cells mature - red bone marrow and thymus
SECONDARY LYMPHOID ORGAN -
areas where mature lumphocytes first encounter their antigen and become activated
INCLUDES
Nodes, spleen, MALT (MUCOSA-ASSOCIATED LYMPHOID TISSUE) and diffuse lymphoid tissue
Spleen
size : a fist, located in left side of abdominal cabity just below stomach
FUNCTION: SITE OF LYMPHOCYTE PROLIFERATION AND IMMUNE SURVEILLANCE AND RESPONSE , CLEANSES BLODD OF AGED BLOOD CELLS AND PLATELETS, MACROPHAGES REMOVE DEBRIS
MALT ( MUCOSA-ASSOCIATED LYMPHOID TISSUE)
Function
protect from pathgens trying to enter body
Location
mucosa of respiratory tract, gentouriany organs, and digestive tract, larges collection of MALT found in
Appendix
offshoot of first part of large intestine
contains a large number of lymphoid follicles
function
Destroy bacteria, preventing them from breaching intestinal wall
generates memory lumphocytes
Peyer's patches
clusters of lymphoid follicles in wall of distal portion of small intestine-
CALLED AGGREGATED LYMPHOID NODULES
location
2 more items...
Tonsils
Location
1 more item...
function
1 more item...
Thymus : bilobed lymphoid organ found in inferior neck - extends into mediastinum and partially overlies heart
Functio- as lymphoid organ where T cells mature
most active and largest in size during childhood
stops growing during adolescence, then gradully atrophies
still produces immunocomprompetent cells, through more slowly
Structure
thymus is broken into lobelues that contain outer cortex and inner medulla
cortex contains rapidly dividing lumphocytes ( the bulk of thymic cells) and scattered macrophages
medulla contains fewer lumphocytes and thymic corpuscles
thymic corpuscels are where regulatory T cells develop
DIFFERENT/DIFF
no follicles because lack of B cells
does not directly fight antigens
functions strictly in T lymphocytes maturation
contains blood thymus barrier: keeps immature T lymphocytes isolated from any antigens to prevent premature activation
stroma is made up of epithelial cells, not reticular fibers
provide environment in which T lymphocytes become immunocompetent
• Purpose and examples of First, Second and Third line of defense
Second line of denfense
antimicrobial proteins, phagoctyes, and other cells
inhibits spread od invaders, inflammation most important mechanism
Activated when surface barriers is breached
protects depper tissue
INCLUDES
phagocytes
natural killer (NK) cells
inflammatory response - Macrophages, mast cells, WBCs, and inflammatory chemicals
Antimicrobial proteins (interforns and complement proteins)
fever
Phagocytes
- White blood cells that ingest and figest (eat) foreign invaders
** Neutrophils: Most abundant phagoctues - - - - Dies - - - - Become phagocytic on exposure to infectious material
Macrophages
develop from monocytes and are chief phagocytic cells; most robust phagocytic cell
Third line of denfesnse
Attacks particular foregin substance-
takes longer to react than innate
First Line of denfense- Surface barriers and secretions
Skin and musus
SURFACE BARRIERS
Physical barrier to most microorganisms
keratin is resistant to weak acids and bases, bacterial enxymes and tocins
mucosae provide similar mechanical barriers
SKIN AND MUCOUS MEMBRANES
produce protective chemical that inhibits or destroy microorganisms
Acid: acidity of skin and some mucous secretions inhibts growth, called ACID MANTLE
Enzymes: Lysozyme of saliva, respiratory mucus, and lacrimal fluid kills many microorganisms; enzymes in stomach kill many microorganisms
Mucin: Sticky mucus that lines digestive and respiratory tract traps microoganisms
SKIN AND MUCOUS MEMBRANES
- * produce protective chemical that inhibits or destroy microorganisms
Acid: acidity of skin and some mucous secretions inhibts growth, called ACID MANTLE
Enzymes: Lysozyme of saliva, respiratory mucus, and lacrimal fluid kills many microorganisms; enzymes in stomach kill many microorganisms
Mucin: Sticky mucus that lines digestive and respiratory tract traps microoganisms
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 mucus toward mouth
• Innate(natural) immune defenses and Adaptive(acquired) immune defenses
Adaptive response
Specfic cells attack specifc antigens
slower response
No restricted to intital site (BIRTHPLACE/ORGIN)
Mounts an even stronger attack to known antigens (second and subsequent exposures)
is systemic: not restricted to initial site
after first exposer of known antegen, the system response and time is stronger and faster
Humoral immunity
B cells
antibodies, produced by lymphocytes, circulate freely in body fluids
bindly temporarily to target cell - TARGETS AND MARKS CELL FOR DESTRUCTION
Cellular immunity
T cells
Lymphoctyes act against target cell
Directly- killing infected cells
Indirectly- by releasing chemicals that enhance inflammatory response OR activating other lymphoctyes or Macrophages
Innate response
No antibodies are needed
Faster
Inflammatory response
Every general, cells will attack anything that is a pathogen/antibody
First line and second lines of denfense
innate defenses do have specific pathways for certain substance
Attacks pathogens
Surface barriers
skin
mucous membranes
Internal denfenses
phagocytes
natural killer cells
inflammation
antimicrobial proteins
fever
Both have quility of -
both release and regonize many of same denfensive molecules
THEY WORK TOGETHER BY
innate response release proteins that alert cells of adaptive system to foregien molecules
• Humoral response and cellular response
Cellular response-
Cellular events
T cells
slower response
Lymphocytes
T ymphocytes
Hemural response-
B cells
Immidate response
Skin and mucus
WHEN ENCOUNTERED BY B CELL THAT HAVES ENCOUNTERS WITH TARGET ANTIGEN, IT
TRIGGERES
Lymphocytes :
B lymphocytes
• Antigens and antibodies
Antibobies-
IMMUNOGLOBULINS (IGS)
PROTEINS secrteded by plasma cells
capable of binding specific with antigen detected by B cells
grouped into one of five IG classes
Anatomy
overall T- or Y-shaped antibody monomer consists of four looping polypeptides chains linked by disulfide bonds
four chains consists of
Two identifical heavy (H) chains with hinge region at "middles"
Two identifical light (L) chains
Variable (V) regions at one end of each arm combine to form two identical antigen-binding sites
stems make up constannt (C) regions
Antibodies
Five major classes
IgM
IgA
IgD
IgG
IgE
Antigens targets and functions
antibodies do not destroy antigens; they inactivat and tag them -
FORM ANTIGEN-ANTIBODY (IMMUNE) COMPLEXES
Denfensive mechanisms used by antibodies
NEUTRALIZATION
AGGLUTINATION
PRECIPITATION
COMPLEMENT FIXATION
NEUTRALATION
SIMPLEST
IMPORTANT
Prevent antigens from binding to receptors on tissue cells
*Antibodies block specific sites viruses or bacterial exotoxins
Antigen-antibody complexes undergo phagocytosis
Complement Fixation and Activation
Main antibody denfense against cellular antigens (bacteria, mismatched RBCs)
When servral antibodies are bound close together on same antigen complement-binding sites on their stem regions are aligned
Precipitation
Soluble molecules (instead of cells) are cross-linked into complexes
complexes precipaitate out of solution
precipated complexes are easier for phagocytes ro engulf
Aggulatination
Allows for antigen-antibodies complexes to become cross-linked into large lattice-like clumps
Process referred to as agglutination
Antigen- The actual sickness . . . mobilizw adaptive denfense and provoke immune response . . . Provokes all immune response . . . ARE LARGE COMPLEX MOLECULES NOT NORMALLY FOUND IN BODY
Self-antigen
Major Histocompatibility complex (MHC)- are part of glycoproteins
*part of self-antigen
MEANS: all cells are covered with variety of proteins located on the surface that are not antigenic to self, but may antigenic to others in surroundings
Contain antigenic determinants
Can be complete antigen or hapten (INCOMPLETE)
• Artificial vs. Naturally acquired immunity
passive
Naturally acquired: antibodies selivered to fetus via placenta or to infant through milk
Artficially acquired: injection of serum - protection immediates but ends when antibodies naturally degrade in body
active
Naturally acquired: formed in response to actual bacterial or viral infection
2, artifically aquired: formed in response to vaccine of dead or attenuated pathogens
• Passive vs. Active immunity
Passive humoral immunity: occurs when ready-made antibodies are introduced into body
B cells are not challenged by antigens, immunogical memory does not occur
protection ends with antibodies humoral immunity
Active humoral immunity- occurs when B cells encounter antigens and produce specfic antibodies against them
• Cells involved in the immune system and their functions
Hempostisis- Formation of cells in the red bone marrow
Lympoid Cells
Natural Killer ( NK) cells
Characteristics:
Nonphagocytic
Large granular lymphocytes that MONITORS BLOOD LYMPH
Can kill canver and virus cells before ADAPTIVE IMMUNE SYSTEM is ACTIVATED
CAUSES APOPTOSIS - A-pop =death of cells
B lymphocytes- Humoral immunity
ACTIVATION AND DIFFEREATION
B cells activared by antigens bind to surface recepotors, cross-linking
Triggers receptor-mediated endocytosis of cross-linking antigen-(
CLONAL SELECTION
) . . . LEADS TO PROLIFERATION ANF DIFFERENTION of B cell into effector cells
most clone cells become
plasma cells
, antibody-secreting effector cells
secrete specific antibodies
antibodies circulate in blood or lymph, binds to free antigens, marking them for destruction by innate or other adaptive mechanisms
Clone cells that do not become plasma cells become
memory cells
provided immunological memory
mount an immediate to future exposer to same antigen
T lymphocytes - Cellular immunity
Lymphocytes - Development, maturation, and activation
Origin: Both lymphocytes originate in red bone marror
Maturation -
REASON-
Immunocompetence: lymphocytes must be able to regonize specific antigen
Self tolerance: must not attack self
EDUCATION
T cells in thymus
B cells in bone marrow
Seeding secondary lymphoid Organs and circulation
immunocompetent B and T cells not yet exposed to anitgen are called NAVIE
exported from primary lymphoid organs (bone marrow and thymus to "seed" (colonize) secondary lymphoid organs ( lymph nodes , spleen, ect)
Antigen encounter and activation
naive lymphocytes first encounter with antigen triggers lymphocytes to develop further
Lymphocyte is selected to differeniate into active cell by binding to its specfic antige - clonal selection
if rights, differentiation into active cell
Proliferation and differentation
once selected and activated lymphocytes proliferates - forms army of exact copies of itself - CLONES
many clones become effector cells that fight infections
some will remain as MEMORY CELLS
Antigen-Presenting cells
ENGULF ANTIGENS AND PRESENT FRAGMENTS OF ANTIGENS TO T CELLS FOR RECOGNITION
Macrophages
Widely distrubuted in connective tissues and lymphoid organs
present antigens to T cells which not only activates T cell, but also further activates marcophages
ACTIVATED
marcophages become
PHAGOCYTIC KILLER
TRIGGERS: inflammatory response and recruit additional defenses
B cells
Do not activate naive T cells
present antigen to helper T cell to assist their own activation
Dendrictic cells (
KEY LINK BETWEEN INNATE AND ADAPTIVE IMMUNITY
)
found in connective tissue and epidermis - act as mobile sentinels of boundary tissue
Phagocytize pathogens that enter tissue, then enter lymphatic to present antigens to T cells in Lymph node
Cellular immune response
T CELLS
T cells provide denfense against intracellular antigens
Some T cells directly kill cells
TWO POPULATIONS OF T CELLS
CD8 cells become Cytotoxic T cells (Tc)
Capable of destroying cells with foreign antigen
Also become memory T cells
CD4 cells usually become helper T cells (Th) that can activate B cells other T cells, and marochages, direct adaptive immune response
Regulatory T cells- moderate immune response
Memory T cells
HELPER, CYTOTOXIC, AND REGULATORY T CELLS ARE ACTIVATED T CELLS
T cells respind only to processed fragmanet of antigens displayed on surfaces of cells by MAJOR HISTOCOMPATBILITY COMPLEX PROTIENS
Activation and Differenation of T cells
T cells can be activated only when antigen is presented to them!!
Activation is a two-step process
both occur on surface on same APC
both are required for clonal selectuon of T cell
co-stimulation
Complete T cell activation requries T cell to also bind to one or more co-stimulatory signals on surface on APC
Antigen binding
T cell antigen receptors (TCRs) bind to antigen - MHC complez on APC surface
TCR must reconginze both MHX and foreign antigen it displays
binding of TCR to complez triggeres multiple intracellular signaling pathways that starts T cells activation
Proliferation and differentiation
T cells that are activated enlarge and proliferation in response to cytokines - differetiate and perform functions according to their T cell clas
Primary T cell reponse peaks within a week
T cell apoptosis occurs between days 7 and 30
activated T cells are a hazard because they produce large amount of inflammatory
could result in hyperplasaia or cancer if not clearted from system
memory T cells remain ad mediate seondary responses
Cytokines
CHEMICAL MESSENGERS OF IMMUNE SYSTEM
Mediate cell development, differentiation, and responses in immune system
INCLUDE INTERFERONS AND INTERLEUKINS
Interleukin 1 (IL-1) is released by macrpphages and stimulates T cells to
release interleukin 2 (IL-2)
synthesize more IL-2 receptors
IL-2 is a key growth factor, acting on same cells that releases it and other T cells
Encourges activated T cells to divide rapidly
Other cytokines amplify and regulate innate and adaptive responses
Helper T (Th) cells
play central role in adaptive immune response
activare both HUMORAL AND CELLULAR ARMS
Once primed by APC presentation of antigen, helper T cells
help activate B cells and other T cells
induce T and B cell proliferation
secrete cytokines that recruit other immune cells
WITHOUT HELPER T CELLS THERE IS NO IMMUNE RESPONSE
Activatation of CB8 cells
CD8 cells require Th cell to become activated into destructive cytotoxic T cells
causes denritic cells to express co-stimulatory molecules required for CD8 cell activation
Amplification of innate denfenses
Amplify responses of innate immune system
Activate macrophages, leading to more ponent killer
Moblize lymphocyres and macrophages and attract other types of WBCs
Activation of B cells
Helper T cells interact directly with B cells displaying antigen fragments bound to MHC II receptor
Stimulate B cells to divide more rapidly and gegin antibody formation
Cytotoxic T (Tc) cells
Directly attak and kill other cells
Activated Tc cells circulate in blood and lymph and lymphoid organs in search of body cells displaying antigen they regonize
activate Tc cells target
( virus-infected cells, cells with intracellular bacteria or parasites, canver cells, foregin cells)
Cytotoxic t cells deliver lethal hit using two mechanisms
Tc cell releases perforins and granzymes by exocytosis -stimulates apoptosis
Tc cell binds specific membrane receptor on target cell and stimulates apapotosis
Regulatory T(reg) cell
important in preventing autoimmune reaction
• Disorders associated with the Immune system
Hepatitis B- caused by the HBV- Hepatitis B virus, attack the liver, and can cause liver cancer or failure.
Pus: creamy yellow mixture of dead neutrophils, tissue/cells and living/dead pathogens
Immunodeficiencies
congenital or acquired conditions that impair function or production of immune cells or molecules
Server combined immunedeficiency (SCID) genetic defect with mark defict in B and T cells
defective adenosisn deaminase (ADA) enzyme allows accumulation of metabolites lethal to T cells
TREATED BY BONE MARROW TRANSPLANT
Hodgkin's disease is an accuiered immunodefincy that cause cancer of B cells- which depresses lymph node cells thus leading to immunodeficiency
Acquired immunedefincany virus (HIV) cripples immune system by interfering with activity of helper T cells
symptoms - weitght loss, night sweats, swollen lymph nodes
Spread- via body fludis: blood, seme, vaginal secretions
hiv enters through blodd transfusions, blood-contaminated needles, sex
0
, oral sex
0
, mother to fetus
HIV destroys Th cell, thereby depressing celluar immuniy
Opportunist infection occur, including PNEUMOCYTIS PNEUMONIA and KAPOSI'S SARCOMA
Auntoimmune diease results when immune system loses ability to distinguish from one self from sickness
autoimmunity production of autoantibodies and sensitized Tc cells that destroys body tissue
Examples
– Rheumatoid arthritis: destroys joints
– Myasthenia gravis: impairs nerve-muscle connections
– Multiple sclerosis: destroys white matter myelin
– Graves’ disease: causes hyperthyroidism
– Type 1 diabetes mellitus: destroys pancreatic cells
– Systemic lupus erythematosus (SLE): affects multiple organs
– Glomerulonephritis: damages kidney
Hypersensitivities: immune reponse to harmless threat for most, that causes tissue damage
Immediate hypersensitivity
also called acute (type I) hypersentivites (allegies)- begin in seconds after contact with allergen, antigen that cuases allegric reaction
initial contact with allergen is ASYMPTOMATIC BUT SENSITIZED PERSON
Activated IgeE against antigen binds to mast cells and basophils
later encounter with same allergen cause flodd of histamine release from IgEs reulting in induced inflammatory response
histamines cause vasodilation and leakiness of vessles, leading to symptoms of runny nose, itchy hives, or even water eyes
ststemic response is
ANAPHLACTIC SHOCK
bronchioles constrict making breathing difficult
vasodilation results in low blood volume, which could cause circulatory collapse
Inflamation:
*triggered when skin is injured
BENIFTS:
prevents spread of damaging agents
disposes of cell debris and pathogens
ALTERS ADAPTIVE IMMUNE SYSTEM
sets the stages of repair
FOUR STEPS OF CARDINAL SIGNS OF ACUTE INFLAMMATION:
1.redness
2.heat
swelling
pain
5.impaired function of area
STAGES OF INFLAMMATION
Inflammatory chemical release
-vasodilation and increased vascular permeability
Phagocytes mobilization
CHEMICALS REALSE DURING INFLAMATION:
chemicals realsed into ECF by injured tissue or immune cells (HISTAMINE- Realsed by MAST cells is key inflammatory chemical)
OTHER MEDIATORS BESIDES HISTAMINE
Kinins, prostaglandis( PGs), cytokine
PURPOSE
all caused vasodilation of local arterioles
all make capillaries leaky
many attract phagocytes to area
Vasodilation and increased VASCULAR PERMEABILITY
PHAGOCYTE MOBILIZATION
Neutrophils flood area first, macrophages follow
inflammation is due pathogens, complement is activated ; adaptive immunity element arive