The Lymphatic System February 2009. Functions drains and filters protein containing fluids from tissue which has escaped from blood capillaries drains.

The Lymphatic SystemThe Lymphatic System

February 2009February 2009

FunctionsFunctions

drains and filters protein containing drains and filters protein containing fluids from tissue which has fluids from tissue which has escaped from blood capillariesescaped from blood capillaries

transport fats from gastrointestinal transport fats from gastrointestinal tract to the bloodtract to the blood

defense – protect the body from defense – protect the body from foreign cells, microbes, cancer cellsforeign cells, microbes, cancer cells

Lymph Lymph vesselsvessels

Major Structures of the Major Structures of the Lymphatic SystemLymphatic System

FluidFluid lymph lymph VesselsVessels lymph nodeslymph nodes

TonsilsTonsils AdenoidsAdenoids SpleenSpleen thymusthymus

Lymph OrgansLymph Organs

Structure DetailsStructure Details

lymphlymph – clear and colorless; – clear and colorless; composed of water, lymphocytes, composed of water, lymphocytes, nutrients, hormones, and salts; nutrients, hormones, and salts; also known as intercellular or also known as intercellular or interstitial fluid. Originates in blood interstitial fluid. Originates in blood plasmaplasma

lymph vesselslymph vessels – carry fluid; more – carry fluid; more permeable than blood capillariespermeable than blood capillaries

LymphLymph

Structure DetailsStructure Details

lymph nodeslymph nodes – small round structures – small round structures located in lymph vessels; they are located located in lymph vessels; they are located in clusters in the following areas: cervical in clusters in the following areas: cervical (neck), axillary (armpits), pectoral (chest), (neck), axillary (armpits), pectoral (chest), abdominal (stomach), inguinal (groin area), abdominal (stomach), inguinal (groin area), popliteal (back of leg, behind knees)popliteal (back of leg, behind knees)

FunctionFunction: they fight disease by producing : they fight disease by producing antibodies, removing bacteria or malignant antibodies, removing bacteria or malignant cells, and filtering foreign substances; contains cells, and filtering foreign substances; contains large amounts of lymphocytes and large amounts of lymphocytes and macrophagesmacrophages

Structure DetailsStructure Details

tonsils & adenoids-tonsils & adenoids- lymph tissue located lymph tissue located in the upper portions of the nose and throatin the upper portions of the nose and throat

spleenspleen – largest lymphatic organ composed – largest lymphatic organ composed of lymph tissue that is located in the left of lymph tissue that is located in the left upper quadrant of the abdomen upper quadrant of the abdomen

FunctionFunction: production of B lymphocytes; : production of B lymphocytes; phagocytizes bacteria and worn out damaged phagocytizes bacteria and worn out damaged RBC; stores and releases blood in case of RBC; stores and releases blood in case of demand demand

Structure DetailsStructure Details

thymusthymus- lymph tissue; located on - lymph tissue; located on top of heart, reaches maximum size top of heart, reaches maximum size in puberty and decreases thereafterin puberty and decreases thereafter

Function: help produce T- cellsFunction: help produce T- cells

Cells of the lymphatic Cells of the lymphatic systemsystem

macrophages – large phagocytic cell macrophages – large phagocytic cell (cells eats bad stuff) (like pacman chew (cells eats bad stuff) (like pacman chew it up)it up)

lymphocytes – originate in the bone lymphocytes – originate in the bone marrow; type of white blood cell that marrow; type of white blood cell that provides immunity provides immunity

Two types T- lymphocytes & B – Two types T- lymphocytes & B – lymphocyteslymphocytes

MacrophageMacrophage

LymphocytesLymphocytes T lymphocytesT lymphocytes – – respond to foreign antigens by respond to foreign antigens by

attaching to the foreign object or cell attaching to the foreign object or cell (interact (interact directly with the cells – called directly with the cells – called cell-mediatedcell-mediated immunity); immunity);

attack cancer cells, but the problem arises when the attack cancer cells, but the problem arises when the cancer cells divide faster than the T cells can kill them. cancer cells divide faster than the T cells can kill them.

4 types – 4 types – natural killer T cellsnatural killer T cells cytotoxic t cells – cause apoptosis or cytotoxic t cells – cause apoptosis or

programmed cell deathprogrammed cell death memory t cells – remember past antigens for quicker memory t cells – remember past antigens for quicker

responseresponse Suppressor t cells – suppress immune system to prevent Suppressor t cells – suppress immune system to prevent

over-reaction to known foreign antigens. over-reaction to known foreign antigens.

Lymphocytes ContinuedLymphocytes Continued

B lymphocytesB lymphocytes – respond to foreign antigens by – respond to foreign antigens by producing producing antibodiesantibodies that destroy the that destroy the antigen-antigen-bearing particlesbearing particles (don’t kill cells directly – called (don’t kill cells directly – called antibody-mediatedantibody-mediated immunity) immunity)

B lymphocytes “taste” foreign antigens, so that B lymphocytes “taste” foreign antigens, so that they can then make appropriate matching they can then make appropriate matching antibodies which can attack the foreign antibodies which can attack the foreign invaders. invaders.

Antibodies (immunoglobulins) – destroy any cell Antibodies (immunoglobulins) – destroy any cell that bearing the matching antigen.that bearing the matching antigen.

Cells of LymphaticCells of Lymphatic

If a microbe that can cause If a microbe that can cause infection gets past your body’s infection gets past your body’s initial barriers (mechanical barrier) initial barriers (mechanical barrier) First line of defense First line of defense (skin, (skin, mucus), T cells are the army troops mucus), T cells are the army troops that do the fighting (B cells are the that do the fighting (B cells are the armed guards that hold a grudge).armed guards that hold a grudge).

Antigen vs AntibodyAntigen vs Antibody

Antigen – proteins, polysaccharides, Antigen – proteins, polysaccharides, lipids that are located on a cells lipids that are located on a cells surface that elicit an immune surface that elicit an immune response. response. Chemical markersChemical markers

Self antigens- proteins that the body Self antigens- proteins that the body cells recognize as cells recognize as “self”“self”

Non-selfNon-self- proteins that the body - proteins that the body does not recognizedoes not recognize

Continued…Continued… Antibody – protein that B cells Antibody – protein that B cells

produce in response to the presence produce in response to the presence of a non-self antigenof a non-self antigen

When an antibody combines with an When an antibody combines with an antigen, it renders the antigen-antigen, it renders the antigen-bearing cell/particle inactive and bearing cell/particle inactive and leads to the destruction of the cell. leads to the destruction of the cell.

Causes agglutination or massing of Causes agglutination or massing of cells together so they can be cells together so they can be destroyed by destroyed by migmig

Agglutination of anitgens with Agglutination of anitgens with matching antibodiesmatching antibodies

Nonspecific Defense Nonspecific Defense

mechanical barriermechanical barrier: physical barrier between : physical barrier between the body and pathogen. Ex: skin, mucous the body and pathogen. Ex: skin, mucous membranes, cilia, epiglottis. membranes, cilia, epiglottis. First line of First line of defense for the bodydefense for the body

species resistancespecies resistance: a given organism develops : a given organism develops diseases that are unique to it. Examples are diseases that are unique to it. Examples are mumps, gonorrhea and syphilis infect humans mumps, gonorrhea and syphilis infect humans but not other animals. but not other animals.

Disease may affect different animals differentlyDisease may affect different animals differently

Nonspecific DefenseNonspecific Defense all except mechanical barrier are all except mechanical barrier are secondsecond line of line of

defense defense chemical barrierchemical barrier: enzymes in body fluid that : enzymes in body fluid that

can damage, kill or make the environment can damage, kill or make the environment uninhabitable for the pathogen. Ex. Gastric uninhabitable for the pathogen. Ex. Gastric juice, tears, salt in sweatjuice, tears, salt in sweat

feverfever: : endogenous pyrogenendogenous pyrogen (protein) raises (protein) raises the set point in the brain for body temperature. the set point in the brain for body temperature. The higher temperature reduces the levels of The higher temperature reduces the levels of iron in the blood that the pathogen needs to iron in the blood that the pathogen needs to survive. Also, phagocytic cells attack more survive. Also, phagocytic cells attack more vigorouslyvigorously

inflammationinflammation: redness, swelling, heat, and pain : redness, swelling, heat, and pain due to a pathogen invasion, inhibits microbial due to a pathogen invasion, inhibits microbial growth. Decreases blood flow through the area. growth. Decreases blood flow through the area.

Specific Defense (Immunity) Specific Defense (Immunity)

ThirdThird line of defense line of defense resistance to particular pathogens or resistance to particular pathogens or

to their toxinsto their toxins cell-mediated immunity – this is cell-mediated immunity – this is

where T-cells, B-cells, and where T-cells, B-cells, and macrophages are activated. macrophages are activated.

Specific Defense (Immunity)Specific Defense (Immunity)

Antibody-mediated immunityAntibody-mediated immunity Immune responsesImmune responses

Primary immune responsePrimary immune response – B cells and T – B cells and T cells are activated and fight the pathogen. cells are activated and fight the pathogen. Anti-bodies are produced (takes 5-10 days Anti-bodies are produced (takes 5-10 days to reach detectable levels)to reach detectable levels)

Secondary immune responseSecondary immune response – Some of the – Some of the B cells activated by the primary response B cells activated by the primary response remain dormant as memory cells; if the remain dormant as memory cells; if the antigen is encountered in the future, the antigen is encountered in the future, the memory B cells immediately begin to memory B cells immediately begin to produce the antibodyproduce the antibody

Active and Passive Active and Passive ImmunityImmunity

Active immunityActive immunity – results when a person – results when a person produces an immune response to an produces an immune response to an antigen that is long-lasting antigen that is long-lasting

Occurs naturally when a person is exposed Occurs naturally when a person is exposed to a pathogen and develops a disease; to a pathogen and develops a disease; person gains resistance by initiating a person gains resistance by initiating a primary immune response.primary immune response.

The primary immune response gives The primary immune response gives immunity or a secondary immune response. immunity or a secondary immune response.

Active Immunity ContinuedActive Immunity Continued

Occurs artificially when a person receives Occurs artificially when a person receives a vaccine (bacteria or viruses that have a vaccine (bacteria or viruses that have been killed or weakened so they can’t been killed or weakened so they can’t cause a serious infection); but they still cause a serious infection); but they still contain antigens that stimulate an contain antigens that stimulate an immune response; doesn’t always last immune response; doesn’t always last for life. for life.

Still activates a secondary immune Still activates a secondary immune responseresponse

Passive ImmunityPassive Immunity occurs when a person receives antibodies occurs when a person receives antibodies

produced by another individual; person does produced by another individual; person does not have an immune response, so immunity not have an immune response, so immunity is short-term is short-term

Occurs naturally when antibodies pass from Occurs naturally when antibodies pass from mother’s blood into fetal bloodstream, also mother’s blood into fetal bloodstream, also thru breastfeeding; fetus acquires immunity thru breastfeeding; fetus acquires immunity against pathogens that mother has against pathogens that mother has developed immunity against; lasts 6 months developed immunity against; lasts 6 months to a year after birthto a year after birth

Occurs artificially when a person receives Occurs artificially when a person receives antiserumantiserum (ready-made antibodies) (ready-made antibodies)

Types of Acquired Types of Acquired ImmunityImmunity Type Mechanism Result

Naturally acquired active immunity

Exposure to pathogens

Symptoms of disease and an immune response

Artificially acquired active immunity

Vaccine Stimulation of immune response without severe symptoms of disease

Artificially acquired passive immunity

Injections of antibodies (antiserum)

Short term immunity without an immune response

Naturally acquired passive immunity

Antibodies passed to fetus

Short term immunity for infant without immune response (lasts 6 mon to 1 yr)

Vaccines Vaccines

mixtures of antigens (killed microbes, mixtures of antigens (killed microbes, those that are unable to cause those that are unable to cause infection, or proteins not recognized infection, or proteins not recognized as self) Administered orally, nasally, as self) Administered orally, nasally, inoculation - not for life – usually inoculation - not for life – usually repeated repeated

Immune System Concerns Immune System Concerns

Three types of immune system Three types of immune system disorders disorders Autoimmune DiseasesAutoimmune Diseases AllergiesAllergies Immunodeficiency'sImmunodeficiency's

autoimmune diseases –autoimmune diseases – a. your system attacks your own self a. your system attacks your own self

cellscells b. Occurs when bacteria/virus causes T b. Occurs when bacteria/virus causes T

cells to attack body’s own macrophage. cells to attack body’s own macrophage. Eventually killer T cells start to view Eventually killer T cells start to view other cells in the body as foreign other cells in the body as foreign

c. Ex. Lupus, Rheumatoid arthritis, c. Ex. Lupus, Rheumatoid arthritis, multiple sclerosismultiple sclerosis

Allergies –Allergies – a. Allergens cause the system to have a a. Allergens cause the system to have a

hypersensitivity reaction which causes hypersensitivity reaction which causes an excessive immune response. Severity an excessive immune response. Severity can change year to year and some start can change year to year and some start late in life – genetics can predispose late in life – genetics can predispose people to allergiespeople to allergies

b. Delayed reaction allergy results from b. Delayed reaction allergy results from repeated exposure to antigens repeated exposure to antigens

Allergies ContinuedAllergies Continued

c. IgE antibodies cause the release of c. IgE antibodies cause the release of histamine …. Initiating allergic histamine …. Initiating allergic reactions which can damage the reactions which can damage the tissues in the bodytissues in the body

d. dilation of blood vessels, increased d. dilation of blood vessels, increased vascular permeabilty, swelling, vascular permeabilty, swelling, contract of bronchial and smooth contract of bronchial and smooth muscles, increased mucous productionmuscles, increased mucous production

Allergies ContinuedAllergies Continued

e. the result is severe inflammation- hives, e. the result is severe inflammation- hives, hay fever, asthma, or gastric disturbanceshay fever, asthma, or gastric disturbances

f. some are seasonal and others are year f. some are seasonal and others are year round (food)round (food)

g. A severe allergic reaction (sudden g. A severe allergic reaction (sudden breathing difficulty) is anaphylaxis can cause breathing difficulty) is anaphylaxis can cause anaphylactic shock which can lead to death – anaphylactic shock which can lead to death – treatment is an epinephrine injection or treatment is an epinephrine injection or tracheotomy. Symptoms of an anaphylactic tracheotomy. Symptoms of an anaphylactic shock: hives, vomiting, diarrhea, face, tongue shock: hives, vomiting, diarrhea, face, tongue and larynx swelland larynx swell

Immunodeficiencies Immunodeficiencies

(acquired immunodeficiency syndrome) is (acquired immunodeficiency syndrome) is caused by HIV (human immunodeficiency caused by HIV (human immunodeficiency virus. HIV targets helper T cells, which virus. HIV targets helper T cells, which makes a person infected unable to fight makes a person infected unable to fight against this virus. against this virus.

Over time, the person is deficient in helper Over time, the person is deficient in helper T cells T cells immunodeficiency. It is acquired immunodeficiency. It is acquired (rather than induced) via lifestyle choices (rather than induced) via lifestyle choices (unprotected sex, intravenous drug use) (unprotected sex, intravenous drug use) or events (blood transfusions)or events (blood transfusions)

ImmunodeficienciesImmunodeficiencies

initial symptoms- weakness, recurrent initial symptoms- weakness, recurrent fever, night sweats, swollen glands, fever, night sweats, swollen glands, weight loss (similar symptoms of the flu)weight loss (similar symptoms of the flu)

latency period- 5-10 years person feels latency period- 5-10 years person feels well, immune system struggles with well, immune system struggles with growing HIV invading cellsgrowing HIV invading cells

AIDS (third stage)-opportunistic infection. AIDS (third stage)-opportunistic infection. Those infected don’t die from AIDS, they Those infected don’t die from AIDS, they die due to the flu, pneumonia, etc die due to the flu, pneumonia, etc because their immune system is so because their immune system is so weak, they can’t fight anymore.weak, they can’t fight anymore.