Anatomy: Ch.20 Lymphatic and Immune System

How does lymphatic and immune system work together

- cells of immune system like B cells, T cells, and macrophages live in lymph node organs like lymph nodes, spleen,and MALT. Also provide place for lymphocyte development -lymphoid tissue traps pathogens for immune system so leukocytes can get to them easier -lymphoid organs activate cells of immune system; macrophages and dendritic cells activate b and T cells; thymus produces functional population of T cells Lymphatic system is more active in adaptive immunity than innate

Appendix

- defends against bacteria in large intestine -easy for bacteria and fecal matter to get trapped in appendix which is know as appendicitis, in which the appendix swells like lymph nodes when your sick and fills with bacteria or pathogens -blind end of appendix gives it little room to expand which creates potential for rupture which spills bacteria into abdominopelvic cavity and leads to internal bleeding which can be fatal -MALT is found here

Thymus

- main function is to generate T cells capable of protecting body from paths - large and active in infants and children; reaches maximum size at 12-14 yrs old - after that age it atrophies and the thymus tissue is replaced with fat, during this time production of T cells decreases also -at 65, T cell production falls to 2% This drop in production does not normally lead to a decline in immune function, however, because of the enormous number of T cells produced during infancy

Functions of the lymphatic system

- regulate interstitial fluid: filtration causes plasma to lose 2-4 liters of water a day to the interstitial fluid, that fluid must be returned to maintain blood volume, pressure and essentially homeostasis. This is done by lymphatic vessels which pick up the excess interstitial fluid, transport it through the body and return it to the cardiovascular system *when interstitial fluid exits extracellular space and enters lymphatic vessels its known as lymph, interstitial fluid and lymph have similar composition.* -absorption of dietary fat: breakdown products of fat are too large to pass through tiny spaces between endothelial cells so instead they enter lymphatic vessels in the small intestine and delivered to blood with lymph -immune functions: lymphoid organs remove pathogens(villain) from lymph and blood and house leukocytes and play a role in leukocyte maturation

Phagocytes: neutrophils (innate immunity)

-Active phagocytes -When activated oxygen consumption increases respiratory burst which allows them to create chemicals like hydrogen peroxide, hypochlorite acid, and hydroxide anions which kill pathogens —can ingest cells but are effective at destroying bacteria -reside in blood and must be sent to tissues by chemical signals

Phagocytes: eosinophils (innate immunity)

-can migrate from blood to tissue when needed -primary response to parasitic paths -when a perosn is infected with parasite eosinophils cover it and release contents of granules which damage and destroys parasites or makes it easier for other cells to destroy it

lymph node structure

-external connective tissue capsule that surrounds a network of reticular fibers filled with macrophages, lymphocytes, and dendritic cells Interior of node is divided into two regions: outer cortex and inner medulla Outer cortex: contains B-cell rich lymphoid follicles divided by inward extensions of capsule called trabelcuae base of cortex contains T-cells inner medulla: contains rows of macrophages and mature B-cells called medullary cords

How do cancer cells evade immune response

-grow too quickly -tumor cells provide poor co-stimulators signals which prevent th and tc activation -low numbers of class I molecules which prevents tc activation -tumor cells secrete cytokines that suppress T cell activity

Phagocytes: dendritic cells (innate immunity)

-most important antigen presenting cells -The substances they ingest are presented to T cells (and, to a lesser extent, B cells), which are then activated

Adaptive - Antibody Mediated Immune response three phases

1. B cell activation, clonal selection and differentiation 2.immunoglobulin mediate destruction of antigens they bind to 3.memory B cells rapidly react to antigens occurring more than once (vaccination)

Adaptive - Antibody Mediated Immunity phase 1

1. B cells are sensitized when they bind to antigen 2.sensitized B cell processes antigen and presents it on its class II MHC molecule which attracts helper T cells which activates B cell 3.B cells differentiate into plasma cells that secrete antibodies and memory B cells respond to second exposure of antigen 4. Plasma cells continue to divide and increase their numbers as they actively secrete antibodies RER IS PROMINENT IN PLASMA CELLS

Class II MHC processing and displaying

1. Cell ingest pathogen by phagocytosis 2.phagocytic vesicles fuse with lysosome and pathogen is degraded and fragmented 3. Lysosome fuses with RER vesicle that contains MHC II and they bind 4.MHC antigen complex is inserted into cells plasma membrane

Class I MHC processing and displaying

1. Cell synthesizes foreign or self antigen 2. Enzymes in cytosol break down antigen 3. Fragments of antigen with antigenic determinate couples with MHC in RER 4.MHC-antigen complex leaves RER by vesicle and insets into cells plasma membrane 1

T cell activation, clinal selection, and differentiation

1. Dendritic cells presents antigen to specific T-cell specific for its MHC-antigen comp0lex. When T cell receptor binds clonal selection happens where antigen selects particular T cell clone 2. Helper t or cytotoxic T cells bind to cosimulator to activate since T cell receptors have low affinity for MHC-antigen complexes which prevents unnecessary T cell activation especially for cytotoxic T cells 3. Helper t or cytotoxic T cells increase in number when activated and differentiate into effector or memory T cells. Effector: produce immediate response Memory: immunological memory to remember antigen and produce rapid response no need for cosimulator

Two ,main components of the lymphatic system

1. Lymphatic vessels 2. Lymphatic tissues and organs including clusters of lymphoid follicles such as tonsils, lymph nodes, spleen, and thymus

Part 1: The Inflammatory Response: Effects of Inflammatory Mediators

1. Tissue damage occurs 2. Damaged cells and mast cells release inflammatory mediators 3. Inflammatory mediators trigger cardinal signs

Fever (innate immunity physiological response)

36 and 38° C (or 97 and 99° F); an individual with a fever is referred to as febrile hypothalamus normally functions as the body's thermostat, and maintains body temperature within the normal range through a series of negative feedback loop Pyrogens released from damaged cells or certain bacteria cause the hypothalamic thermostat to reset to a higher range and interprets normal body temp as too low which triggers negative feedback loop and is why u feel chills phagocytes function more efficiently at a slightly higher body temperature, which helps to increase the rate of recovery from whatever caused the inflammation. antipyretics: reduce inflammation-mediated fever, Most antipyretics work in the same manner as anti-inflammatories, by inhibiting the formation of prostaglandin causes (sweating, dilation of blood vessels, making u feel hot even tho body temp is decreasing)

Hypersensitivity immune disorder

4 types according to the exact immune components causing the hypersensitivity Type 1: most common, immediate, allergies, plasma cells secrete IgE instead of IgG or IgM. Anaphylactic shock needing epinephrine epi pen Type 2: antibody mediated, antibodies bind to self antigens in 3 situations. bind to self antigens. This reaction occurs in three situations: (1) Foreign antigens bind to normal self antigens; (2) donor erythrocytes infused into an individual are mismatched in the ABO/Rh antigen groups; and (3) self-reactive B cells are not destroyed in the bone marrow, which leads to autoimmunity Type 3: immune complexes that weren't destroyed phagocytes, difficult for macrophages to ingest ,initiate an inflammatory reaction that attracts neutrophils and causes damage to the affected areas. Type 4: delayed type, mediated by T cells instead of antibodies TH cells recognize antigens bound to MHC molecules as foreign and mediate their destruction by activating and recruiting macrophages and in some cases TC cells. This reaction generally takes 2-3 Contact dermatitis: skin comes into contact with an allergen such as the oils in poison ivy or poison oak, certain metals, or other chemicals that can form complexes with skin proteins Other forms of DTH are caused by intracellular pathogens that are not easily cleared by the immune response.Mycobacterium tuberculosis, which causes the respiratory infection tuberculosis

Rejection of organ or tissue transplant

A rejected organ or tissue first fails to function properly, and then its cells die as TC cells destroy them, a condition known as necrosis. Rejection can lead to the death of the transplant recipient from organ failure and from blood clots and other complications of necrotic tissue

How is immunity classified

According to the way it responds to pathogens and forms of cellular injury

Difference between passive and active immunity

Active Immunity- Individual makes their own antibodies, received naturally or through vaccination. This gives long term immunity because memory cells form. Passive immunity- Individual gets ready made antibodies from mother or injection with preformed antibodies. Short term immunity because no memory cells. Important for infants and exposed to animal venom

Are thymic lobules found in adult or child thymus

Adult Also called thymic corpuscles, contains two regions: outer cortex and inner medulla Cortex: densely packed T cells Medulla: few T cells and site of destruction of certain populations of T cells that could react to the body's own cells

Functions of secreted antibodies

Agglutination and precipitation: IgM because of it 10 antigen binding sites, agglutination is clumping and precipitation is similar and only involves soluble antigens (proteins and biological molecules) instead of whole cells. Both processes allow antigen-antibody complexes to precipitate out of body fluids and make phagocytosis easier Opsonization: IgG are opsonis taht coat pathogens and bind, actiavte and enhance phagocytosis Neutralization: IgG or IgA, blocking, antibodies bind to bacteria and viruses and block them from affecting other cells Complement activation: blood rejection, IGM or IgG, bind and activate complement proteins, several antibodies bind a single cell, their complement-binding sites are exposed. This allows complement to activate and lyse the foreign cell with its membrane attack complex. This effect is particularly important in defense against cellular pathogens such as bacteri Stimulation of inflammation: IgE triggers inflammation by initiating the release of inflammatory mediators from mast cells and basophils. Antibodies also trigger inflammation indirectly through their activation of complement

ORGAN AND TISSUE TRANSPLANSTS/GRAFTS

Autografts: tissue transplanted from one part of the body on the same individual to another part. Ex. Skin grafts for burns Isografts: uncommon grafts of tissues and organs between genetically identical twins Allografts: most common grafts between non identical individuals of same species Xenografts: rare grafts of organs and tissue between individuals of different species Autografts and isografts to not produce response from cytotoxic T cells because they aren't foreign but allografts and xenografts do reject

Class switiching

B cell clone that starts out producing a certain class of antibody, such as IgM, has the ability to switch to production of a different class, such as IgG. The mechanism that allows for this process, known as class switching, involves genetic rearrangements to yield different antibody C regions, while maintaining the same antibody V regions. In this way, the antibody can have different effects while binding the same type of antigen.

Cells of adaptive immunity

B cells and T cells (lymphocytes) Proteins: antibodies and cytokines

The thymus lacks

B cells and lymphoid follicles

BACTERIAL INFECTION

Bacteria damage cells and induce an inflammatory response, as local macrophages ingest the bacteria (strep throat) Neutrophils enter the area in large numbers and phagocytize bacteria, They also trigger the bone marrow to release its store of neutrophils and increase their production, adaptive immunity may or may not be used In lymphatic tissue, dendritic cells activate TH cells, and B cells bind bacterial antigens and are activated by TH cells B cells differentiate into plasma cells that secrete antibodies to agglutinate bacteria TH cells secrete cytokines that enhance phagocyte and B cell activity

Basophils and mast cells innate immunity

Basophils-mediate inflammation -located in blood -mast cell located in mucous membrane and contain chemicals that trigger inflammation

Lymph nodes

Bean shaped cluster of lymphatic tissue located along lymphatic vessels - they filter lymph Located in axillae under armpit (axillary lymph nodes), cervical lymph nodes in the neck, Inguinal lymph lids in the groin, and mesenteric lymph nodes in the abdominal cavity around abdominal organs

Cancer

Cancer cells are mutated cells that become less specialized, lose control of cell cycles and lose attachment to cells and ECM Malignant tumor: metastasize and spreads to other parts of body cancerous, indefinite growth Benign: do not metastasize not cancerous Immune surveillance: T cells and NK cells scan the cells in the body for tumor antigens, critical to prevent tumor development When tumor cells are discovered: 1. Cancer cells invade healthy cells which secrete inflammatory mediators 2.inflammatory mediators attract NK cells to the area and they secrete interferons which kill cancer cells, activate macrophages that secrete tumor necrosis factor which kills cells 3.dendritic cells ingest cellular debris form tumor death, dendritic cells move to lymph and lymph nodes and present antigens to naive tc and th cells 4.Activated TH cells secrete cytokines that stimulate effector TC cells to kill cancer cells : Il-2 activates tc cells which can destroy any cancer

Activated complement proteins (innate immunity) leads to what 5 events

Cell lysis: some complement proteins can pop the plasma membrane of pathogens by binding to the surface and creating docking site for other complement proteins which forms membrane attack complex MAC which inserts itself on the plasma membrane of the target cell creating a pore that pops Enhanced inflammation: complement proteins like c5a and c3a trigger basophils and mast cells to release chemicals that mediate inflammation Neutralized viruses: binding to viruses and blocking them from infecting host cells Enhanced phagocytosis: c3b acts as protein opsin, opsonization makes phagocytes bind more strongly to pathogens ion crease phagocytosis Clearance of immune complexes: C3b also binds to immune complexes—clusters of antigens bound to antibodies— and triggers their phagocytosis. This clears these complexes from the circulation, which is critical to preventing them from lodging in different tissues around the body.

cells and proteins of innate immunity

Cells: phagocytic cells(macrophages, neutrophils, eosinophils, and dendritic cells) Nonphagocytic cells: NK cells and basophils Proteins: complement proteins and cytokines

How pathogens evade surface barriers

Collagenase-producing bacteria: degrade collagen, allows them access to deeper tissues such as skeletal muscle, eventually resulting in massive tissue death and produce large quantities of gas leading to gas gangrene ,C. perfringens also produces enzymes that catalyze the destruction of neutrophils, making the immune system much less able to respond to the invasion. Phagocytosis-resistant fungi: some cells are resistant to phagocytosis, blastymocycosis have thick walls that are hard for phagocytes to ingest, cryptococcosis and histoplasmosis survive in macrophages making fungi invisible to immune system and spreads through blood Acid tolerant pathogens: But certain pathogens tolerate or even prefer an acidic pH.

Endogenous and exogenous antigens

Endogenous: self or foreign, foreign antigen living on pathogen that lives inside your cell or foreign or self antigen encoded by your DNA Exogenous: foreign, foreign antigen originated outside of cell and must be taken in by phagocytosis

Vaccine

Expose individuals to antigen to elicit primary immune response so when they are exposed again secondary immune response will occur Several types depending on components: Live, attenuated vaccines: bad for compromised immune systems because of small risk that organism could revert to pathogenic form. Ability to cause disease is reduced and they can still divide and generate primary response Inactivated: require boosters(repeated vaccination) because they produce weaker primary immune response since pathogen is inactive and cannot divide Subunit: require boosters, only the portion of the pathogen that causes disease is required to develop immunit

Lines of defense against pathogens

First line of defense: cutaneous(skin) and mucous membranes act as surface barriers to block entry of pathogens into body Second line of defense: responses of cells and proteins of innate immunity Third line of defense: responses of cells and proteins of adaptive immunity

When blood enters spleen where does it go

Flows through a series of arterials until it reaches sinusoids which is the spleens large leaky capillary. At the sinusoids pathogens in the blood encounter macrophages and dendritic cells which process portions of the pathogens

Describe structure of the white pulp of the spleen

From deep to superficial... white pulp has a center zone containing mostly T cells, next this center zone surrounds central arteries, next outside of the central zone are lymphoid follicles composed of central core of B cells, and last on the outer rim of white pulp are macrophages, dendritic cells, and some B and T cells

Immunogens (antigens)

Generate an immune response Self antigens are not immunogens in your own body Happens are only immunogens when bound to protein carrier(urushiol toxin in poison ivy enters the skin, oxidized, and binds to skin proteins)

Antigen

Generate production of antibodies from B cells Usually peptides but can be carbohydrates, lipids, and metals (nickel is a notoriously antigenic metal). These other than peptides must be coupled with a peptide to function fully as an antigen.

Effects of active helper T cell

Helper T cell role: Helper T cells secrete cytokines that activate and enhance components of immune response Innate immunity: helper T cells secrete cytokine Interleukin-3 which stimulates macrophages to become more efficient phagocytes and stimulates macrophages to produce more interleukin-12 which makes helper T cells make more IL-3 Adaptive cell-mediated immunity: helper T cell secrete cytokine IL-2 which activates and proliferates(multiplies) cytotoxic T cells Adaptive antibody-mediated immunity: helper T cells directly binds to Bcells and releases IL that stimulate Bcell proliferation and differentiation and increase antibody production

Common cold

High mutation rate so there is no vaccine Most viruses are detected by surface barriers and dont enter body When virus does enter body response occurs: 1.The virus enters through the respiratory tract and infects local cells. This triggers the infected cells to secrete certain interferons and other inflammatory mediators that initiate the inflammatory response. 2. The interferons secreted by the infected cells travel to nearby cells and prevent viral infection. Interferons also bind and activate NK cells, which begin destroying infected cells. 3.Dendritic cells activate TH and TC cells in lymphatic tissue, and cytokines from TH cells activate B cells bound to viral particles 4.The activated B cells differentiate into plasma cells and memory B cells. The plasma cells secrete antibodies that bind to the viral particles and neutralize them, preventing them from interacting with the human host cells. 4.TH cells secrete cytokines that amplify the immune response, and TC cells destroy virally infected cells

Challenges to vaccines

High rates of pathogen mutation change the pathogens' antigens, which alters the B cells and antibodies needed to respond to those antigen HIV, tuberculosis, influenza Vaccines eliminated polio and smallpox

Graft rejection prevention

Human leukocyte antigen screening- allografts antigens are as similar as possible to recipient antigens, screens antigens most likely to reject. A donor individual who has a high percentage of HLA similarity to the recipient is said to be a match. Exact HLA matches are rare and most likely to be found within family's, siblings are 25% chance match Exact matches arnt neccesry 1-2 mismatches out of 4 are good Immunosuppressive therapy- risky suppressing the immune response with medications

3 disorders of the immune system

Hypersensitivity: immune system overreacts and damages tissues Immunodeficiency: components of immune system fail Autoimmune: treat self-antigens of foreign and attack bodies own tissues

5 classes of antibodies GAMED

IgG: 75-80% of antibodies, passed form mother to child in placenta, monomer IgA: dimer, mucous membrane, skin, exocrine glands(tears, sweat saliva, bre ast milk) IgM: M FOR MASSIVE PENTAMER, first to be secreted, also exits as monomer in B CELL plasma membrane as receptor IgE: monomer, low amount sin body, binds to 2 antigens, 1. Parasitic pathogens tapeworms and 2.allergic pathogens trigger mast cells to release the contents of their granules, a process called degranulation. Mast cell granules contain inflammatory mediators such as histamine that initiate a localized inflammatory response, run by nose, tears IgD: monomer not secreted by B cells in significant amounts, B cell receptor

Types of immunity

Innate (nonspecific) immunity: -responds to all pathogens the same way -responds quickly within first 12 hrs because cells and proteins are always present in bloodstream even without stimulus Adaptive(specific/acquired immunity): -cells and proteins respond specifically to individual antigens -must be exposed to specific antigen for response to initiate -takes 3-5 days to initiate then its the dominant responses -immunological memory: exposure to antigen is remembered by lymphocytes and antibodies and allows rapid and efficient response when exposed again Cell mediated adaptive immunity: brought about by two types of T cells Antibody mediated adaptive immunity: carried out by B cells and proteins they produce called antibodies INNATE AND ADAPTIVE IMMUNITY NEED EACH OTHER TO FUNCTION PROPERLY IF THEY DONT IMMUNE SYSTEM CAN FAIL

Effects of active cytotoxic T cells

Kill foreign antigens bound to class I MHC molecules they can detect abnormalities in any cell type with a nucleus, which is critical for the detection of cancer cells, foreign cells, and cells infected with intracellular pathogens such as viruses and bacteriA require IL-2 from TH cells to activate fully TC cells also bind to proteins on the plasma membrane of target cells that induce the process of apoptosis, or programmed cell death

What are the capillaries that collect fat in small intestine called

Lacteals

Mucosa associated lymphatic tissue (MALT)

Loosely organized cluster of lymphoid tissue located along mucous membranes ( gastrointestinal tract, respiratory passages, genitourinary tract) Mostly consist of B and T cells Specialized MALT are encapsulated by connective tissue

Are lymphatic veins under low or high pressure

Low pressure circuit because there is no pump to drive lymph through vessels; lymph flow through vessels is driven by contractions of smooth muscle in the walls of lymph collecting vessels, contraction of muscle, and valves Because lymphatic vessels are transporting lymph against gravity they have lymphatic valves to prevent back flow Found lodged between muscles where the contracting muscles ,massage lymph up toward heart

Lymph is collected in

Lymph collecting vessels which merge to from lymph trunks, there's are nine lymph trunks that drain from specific areas in the body Lumbar trunks: receives lymph from lower limb and pelvis area Intestinal trunk: receives fat contains lymph from small intestine Jugular trunks: receives lymph from head and neck Bronchomediastinal trunks: receives lymph from thoracic cavity Subclavian trunk: receives lymph from upper limbs

How are blood capillaries and lymphatic capillaries different

Lymphatic capillaries flow one way only moving lymph away from tissues; blood flows both ways on blood capillaries Endothelial cells in blood capillaries are tightly joined unlike lymphatic endothelial cells

What happens if lymph vessels are blocked or flow is interrupted

Lymphedema removal of lymphatic vessel during surgery or pathogens blocking vessels can prevent the lymphatic vessels from returning the excess interstitial fluid back to the cardiovascular system, so it accumulates in the tissues and causes affected area to swell Picture: breast cancer patient had surgical removal of lymph nodes

What are the cell types in lymphoid tissues and organs

Lymphocytes: B and T lymphocytes/ B and T cells are agranulocytosis that function in immunity Phagocytes: two types which are macrophages and dendritic cells. Macrophages are mature monocytes that are active phagocytes(get rid of cellular debris). Dendritic cells are leukocytes with spiny processes that activate lymphocytes Reticular cells: abundant in spleen and lymph nodes, reticular cells produce reticular fibers which are composed of specialized thin collagen protein

Phagocytes: macrophages (innate immunity)

Monocytes, neutrophils, and eosinophils can act as phagocytes -monocytes become macrophages in the tissues, some remain fixed in certain tissues and others roam freely -activated by substances on pathogens, chemicals secreted by damaged cells, and signals from cells of adaptive immunity -macrophages are usually first cell to respond to cellular injury -macrophages kill pathogens they have ingested with chemicals, including hydrogen peroxide and hypochlorous acid -macrophages have cytosol effects meaning they can secrete those substances on pathogens that are to large to ingest -act as antigen presenting cells that display antigens they ingest on plasma membrane which activates T cells and T cells secrete substances that increase activity of macrophages positive feedback loop

Does the immune system have its own organs or tissues ?

No, it has cells and proteins located blood and tissues of other organs.

How do pathogens cause infection

Pathogens are microorganisms that cause infection by invading a tissue, increasing in number and causing cellular damage Microorganism can be bacterial cells, viruses, fungi, and parasites Cancer cells, bacterial toxins, and toxins found in animal venoms are also pathogens

How are peyers patches exposed to potential pathogens

Peyers patches are locate din small intestine and small intestine joins with the large intestine, which houses bacteria which are not harmful to large intestine but if they gain entry to small intestine they could cause disease

Primary and secondary lymphatic organs

Primary: Red bone marrow: PRODUCES FORMED ELEMEMTS OF BLOOD INCLUDING LYMPHOCYTES (B AND T CELLS) Thymus:matures T cells although 99% dont make it Secondary: lymph node-lymphocyte activation and cloning and filters lymph spleen-filters blood, immune defense against bacteria tonsils-lymphocyte activation and cloning, present in respiratory tract Peyer's patches in small intestine Primary: MAKE AND MATURE lymphocytes Secondary: sites of lymphocyte ACTIVATION AND CLONING

Differences between primary and secondary immune response

Primary: IgM takes longer, you feel sick during lag phase Secondary: IgG, quicker, antibodies secreted are more effective, last longer

organs of the lymphatic system

Primary: thymus and red bone marrow Secondary: Tonsils,lymph nodes, spleen, mucosa associated lymphatic tissue(not organ)

Immunity (hero and villain)

Processes that protect the body from cellular injury and pathogens (diseases causing cells and substances) Immunity is the hero and pathogens are villains Crucial to homeostasis which is why diseases like AIDS are so based because they destroy components of immune system (why auntie dee is always sick)

Complement proteins

Proteins of innate immunity Consist of 30 plasma proteins produced by the liver Circulate in their inactive form and must be activated (can be done in 3 ways): Classical pathway: inactive complement protein binds to antibody on pathogen thats bound to antigen Lectin Pathway: protein lectin binds to carbs on surface of microbes Alternative pathway: cleavage of c3 into c3b which can also occurs when inactive complement proteins encounter foreign cells like bacteria 3 pathways come together when c3b is activated which activates c5b

Cardinal signs of inflammation (innate immunity)

Redness, heat, swelling(edema(, and pain Redness/heat: Hyperemia accounts for the redness and heat that accompany inflammation caused by vasodilation (because blood is warmer than the body's surface) Swelling: Inflammatory mediators increase the permeability, or "leakiness," of local capillary beds. This allows protein-rich fluid to leak from the blood vessels into the tissue spaces, and leads to the cardinal sign of swelling. The proteins in the fluid include clotting proteins such as fibrinogen, complement proteins, and proteins needed for tissue repair Pain: bradykinin and prostaglandins, trigger action potentials in the peripheral processes of sensory neurons. This leads to the extremely important and underappreciated effect of pain, which serves numerous protective functions. Pain lets us know when our tissues are being damaged so that we can try to avoid further damage Chemotaxis: Inflammatory mediators attract and activate a number of leukocytes, particularly macrophages and neutrophils. Note that as this is occurring, complement proteins are also being activated.

Process of how lymph node filters lymph

Remember lymph nodes main function is trapping pathogens to stop them from flowing to the rest of the body(traps 90%of pathogens) 1. Lymph flows into node through afferent lymphatic vessels 2. In the node, it enters hollow area called subscsapular sinus and then flows through cortical sinuses that run next to inward trabeculae 3. As lymph passes through cortical sinuses, pathogens and immune cells like dendritic cells move into into the lymphoid nodule to initiate an immune response 4. Lymph continues to flow from cortical sinuses to medullary sinuses and drains out through efferent lymphatic vessels at the hilum When pathogens enters lymoh node B-cells are activated and causes germinal centers of lymphoid follicles to swell which is called swollen glands (term is incorrect lymph nodes are not glands) Bacterial and viral infections cause swollen lymph nodes to become painful, allergies and cancerous cells causes nodes to enlarge with little pain

What organ protects the body from pathogens in blood

Spleen the largest lymphoid organ in the body - Located on later side of left upper quadrant of abdominopelvic cavity -consist of reticular fibers -within the spleen there are two regions: red pulp and white pulp -red pulp: contains macrophages and destroys old erythrocytes -white pulp: filter pathogens from the blood and contains leukocytes

The lymphatic and immune system are similar in

Structure and function

1st line of defense

Surface barrier: -cutaneous(skin) and mucous membranes provide physical barrier to block pathogens from entering the body -keratin in the epithelial tissue of skin makes it resistant to mechanical stress -mucous membranes line passageways in the body that open to the outside like respiratory, gastrointestinal, and genitourinary -mucous membrane epithelia lack keratin so are thinner then skin epithelia and less resistant to mechanical stress protective secretions: -sebum: secreted by sebaceous glands in skin, oily acidic mixture that deters growth of most pathogenic organisms -mucous: secreted by mucous membranes, thick stick substance that traps debris and pathogens and protects underlying cells from mechanical stress -cilia in respiratory tract beaut in unison to propel substances trapped in mucous out of respiratory tract -mucosa of stomach secrete acid which kills ingested pathogens -defensins: cells of skin produce defensins which are antimicrobial peptides that damage membrane of pathogens -normal flora: non disease causing bacteria that compete with pathogens for space and resources which limits growth, they also secrete substances that kill bacteria, and acidify surface barriers to deter growth of pathogens

T cell maturation

T cells are produced in bone marrow then enter the thymus to be matured which includes gene rearrangement to form distinct T-cells that have T cell receptors for specific antigens. Population of T cells that can respond to a specific antigen are called Clones, not all T cells are clones and are destroyed either because they are self recitative( see self antigens as foreign and destroys them) or not immunocompetent (cannot respond to foreign antigens) The cells that do survive are naive T cells and must bind with specific antigen to be activated, they reside in blood, lymphoid tissue, and lymphoid organs

AIDS

TH cells are required for normal function of all components of the immune system, including innate, antibody-mediated, and cell-mediated immunity. For this reason, failure of TH cells to function, which we see with conditions such as acquired immunodeficiency syndrome (AIDS), can lead to failure of the entire immune response

How does the lymphatic system control the amount of fluid between cells

The endothelial cells lining the walls of the lymphatic capillaries are lose and flap open, when pressure in the interstitial fluid rises (from fluid being lost from blood capillaries) it forces the cells apart and large amounts of interstitial fluid flows in lymphatic capillary becoming lymph. When the pressure in interstitial fluid decreases the endothelial cells flap shut Vessels are leaky enough to allow macrophages and other immune cells in also

HIV

The first phase, the acute phase, lasts about 3 months and is characterized by a sharp decline in TH cells and a sharp rise in HIV-1 virions. Patients may exhibit flu-like symptoms during this phase, although the condition often goes unnoticed. The second phase, the chronic phase, begins with the production of antibodies to HIV-1 virions, an initial slight recovery in the number of TH cells, and a decline in the number of HIV-1 virgins 8 years It is during the final phase when an individual is said to have AIDS, which is characterized by progressively declining numbers of TH cells and progressively increasing numbers of HIV-1 virions. Without treatment, the duration of the final phase is generally no more than 3 years There are three main mechanisms by which most of these drugs work: (1) inhibiting reverse transcriptase, (2) inhibiting viral enzymes needed to synthesize mature virions, and (3) blocking the entry of HIV-1 into its target cells No cure

How do pathogens enter lymphatic capillaries

The same permeability of the endothelial cells of lymphatic capillaries that allows interstitial fluid to leak in also allows pathogens like bacteria and cancer cells from interstitial fluid to enter capillaries as well. So these pathogens can spread to other parts of the body via lymphatic system But lymph nodes limit spread of pathogens by acting as filters and trapping them and preventing the m from spreading (spider web)

SEROLOGY

The study of antibodies derives from the antibody-containing fluid called serum, which is the part of blood that is left over when you remove the cells, platelets, and clotting proteins from the rest of the plasma

Two lymphatic ducts

Throacic duct: cisternae chyli and trunks from left side of body drain into this duct; largest lymphatic duct. Drains all of the lower body and left side of upper body Right lymphatic duct: trunks from right side of the body drain into this duct

Cytokines (innate immunity)

Tumor necrosis factor: TNF death of tumor cells, secreted by macrophages, effects include inducing flu like symptoms of fever chills and aches, attracting phagocytes to infected area, and stimulating phagocytes to release more cytokines. In severe infections, increase in TNF can cause septic shock(low bp, kidney/liver failure, bad blood clotting, low blood glucose) Interferons: interfere with ability of pathogens to infect other cells, inhibit viral replication inside host cells, activate component of innate and adaptive immunity like stimulating cells to produce antimicrobial proteins and flu like responses muscle aches and fever Interleukin

What is the predominant tissue of the lymphatic system

Type of loose connective tissue called reticular tissue which is just called lymphoid tissue in lymphatic system Contains reticular fiber that from webs/nets that trap pathogens Lymphoid tissue is also located in independent structures

Cell mediated adaptive immunity

Use T cells, specifically helper T cells/CD4 cells and cytotoxic cells/CD8 cells CD" stands for "cluster of differentiation," which refers to specific molecules within the plasma membrane that differentiate one cell type from another Respond to cells infected with intracellular pathogens, cancer cells, and foreign cells such as those from a transplanted organ.

How do pathogens evade immune response

Virus block cytokines from releasing interferons viruses are able to block display of viral antigens on class I MHC molecules, which prohibits TC cell activation. adaptations that allow them to attach more strongly to host cells, secretion of substances that destroy antibodies, and inhibition of phagocytes

Germinal centers

When lymphoid follicles/nodules are exposed to pathogens they develop light staining regions where the B cells are actively dividing In gastrointestinal tract they are found in three locations: 1) tonsils in oral and nasal cavity, 2)peyer's patches/ aggregated lymphoid nodules/follicles in the ileum of small intestine 3)appendix of large intestine

Antibody structure and classes

Y shaped protein formed from 4 peptide chains, 2 heavy H chains and 2 light L chains Constant region: similar among antibodies and responsible for antibody effects Variable region: unique sequences of amino acids responsible for antigen recognition and binding with 2 antigen binding sites one on each arm Single: monomer Dimer: two subunits Pentamer: 5 subunits

Does the lymphatic system have its own organs and tissues?

Yes, it has organs and tissues that function in immunity and fluid homeostasis.

What causes pus formation?

dead neutrophil and macrophages collections, dead tissue cells, and fluid pus indicates only that an inflammatory response took place Pus filled wound is purelent, pyogenic bacteria, are known for producing quite purulent wounds. The pus is generally absorbed into the surrounding tissues and lymphatic vessels when healing has completed.

Immunodeficiency

decrease in the function of one or more components of the immune system primary immunodeficiencies, which are genetic or developmental in nature, and secondary immunodeficiencies, which are acquired through infection, trauma, cancer, or certain medications Primary are more common

Part 2: The Inflammatory Response: Phagocyte Response

divide the arrival and activation of phagocytes into stages, based on which phagocytes enter the area and the processes occurring there 1. Within minutes local macrophages already present in tissue enlarge and phagocytize pathogens which contains invading pathogens 2. Neutrophils leave blood and enter tissue because inflammatory mediators make the capillary endothelium in the damaged area "sticky," and the neutrophils adhere to the capillary wall, a process called margination. The inflammatory mediators also increase capillary permeability, as we discussed earlier, which provides enough spaces between endothelial cells for neutrophils to squeeze through into the damaged tissue. This is a process known as diapedesis Once the neutrophils are in the tissue, they then begin to destroy bacteria and other cellular debris, after ingesting a single microbe, neutrophils die also so neutrophils in bone marrow are released so they're circulating at all times 3. Monocytes migrate to tissue and become macrophages and ingest pathogens and damaged cells, slower processes than neutrophil because monocytes take hrs to mature and there a fewer of them in circulation but they live longer and are more aggressive 4. bone marrow increases production of leukocytes, leading to leukocytosis: cytokines increase neutrophils and monocytes over 4 days which leads to elevated numbers of leukocytes allowing the damaged area to be cleared and any pathogens removed so that cells such as fibroblasts can begin the process of healing

What is lymph

excess interstitial fluid carried by lymphatic vessels

Why do u feel sick

inflammatory response triggers increased blood flow and capillary permeability in the upper respiratory tract, and the fluid that leaks out of capillaries tends to leak out of your nose. Interferons cause fever body ache cold viruses mutate rapidly, and new strains for which you lack memory cells emerge every year. Your body must mount a primary immune response for each new type of mutated virus, which takes time to complete. During this time, you feel sick as the virus does local damage and your immune system works to combat it.

3 main tonsils

pharyngeal (adenoid) tonsil: posterior nasal cavity palatine tonsils: posterolateral oral cavity lingual tonsils: base of tongue epithelium lining the tonsils indents deeply in several locations, forming tonsillar crypts that trap bacteria and debris Tonsils location puts them in contact with a large number potential pathogens and they become inflamed (tonsillitis)

natural killer cells (NK cells) innate immunity

recognize cancerous cells and cells infected with certain viruses in spite of the fact they cannot recognize antigens do this by scanning the cells for irregularities and by reacting to cells that have bound to antibodies cytotoxic, releasing substances that destroy their target cells. In addition, they secrete an antimicrobial cytokine that activates macrophages and enhances phagocytosis.

Autoimmune disorder

self-reactive T cells or of B cells that secrete antibodies that bind to self antigens, called autoantibodies Autoimmune disorders may be localized and affect only one organ or tissue, or they may be systemic and affect multiple parts of the body. Autoimmunity results in a type II, III, or IV hypersensitivity reaction, which is what produces the organ and tissue damage characteristic of the disease Many situations could lead to the development of autoimmunity, including the following: Release of self antigens not previously encountered by T cel Foreign antigens mimic self antigens if an individual comes into contact with these pathogens, co-stimulatory signals activate these T cells, which then attack self cells Cells may inappropriately express class II MHC molecule Certain pathogens nonspecifically activate B cells.

Where is MALT found?

tonsils, peyer's patches(small intestine), appendix(large intestine)