Chapter 22 Lymphatic System Nonspecific Resistance to Disease

Splenctomy

(removal of the spleen) is required to prevent death from blood loss.

Antibody - Mediated (Humoral) Immunity (AMI) (referring to B cells)

1. The body contains not only millions of different T cells but also millions of different B cells, each capable of responding to a specific antigen. Whereas cytotoxic T cells leave lymphoid tissue to meet a foreign antigen, B cells stay put.

What 3 things help in lymph flow?

1. skeleton muscle contractions 2. respiratory movements 3. aided by valves.

T cells consist of several subpopulations, name them

1.) Helper T (TH) cells or T4 cells, 2. ) Cytotoxin T (Tc) cells or T8 cells, 3). Delayed - type hypersensitivity T cells, 4). Suppressor T (Ts) cells 5). Memory T cells

plasma cells produce an at an incredible rate of

2000 molecules per second per cell for 4-5 days until the plasma cell dies.

Antibodies to HIV are usually developed within

3-20 weeks after exposure; however, these antibodies are not generally protective and are primarily useful in diagnosis of HIV infection.

Thymus

A bilobed organ that secretes hormones (thymosin and thymopoietin) that cause T lymphocytes to become immunocompetent

Explain why the lymphatic system is a one-way system, whereas the blood vascular system is a two-way system.

Blood vessels form a complete circuit from and to the heart. The lymphatic system lacks arteries and begins with blind-ended lymph capillaries. it is a "return" system only.

Hemopoieses

Formation of new RBC's, usually in bone marrow

Spleen characteristics

Largest lymphatic organ Located in left upper abdominal quadrant inferior to diaphragm and adjacent to ribs 9-11 lateral to left kidney and posterolateral to stomach Posterolateral aspect convex and rounded Concave anteromedial border contains hilum, where blood vessels and nerves enter

Spleen

Largest lymphoid organ, located on the left side of the abdominal cavity beneath the diaphragm It is served by the splenic artery and vein, which enter and exit at the hilus a. it stores platelets b. it produces red blood cells in the fetus c.it removes debris and foreign matter from the blood.

Lacteals

Lmpyhatic capillaries located within the gastrointestinal (GI) tract, they allow for the absorption of lipid-soluble substnces from the GI tract. Specific lymphatic capillaries in the small intestine.

MALT - Mucosa-associated lymphatic tissue

Located in gastrointestinal, respiratory, genital, and urinary tracts found in lamina propria of the mucosa Help defend against foreign substances Prominent in small intestines, especially ileum Peyer patches, found here large collections of lymphatic nodules

What is the function of the lymphatic vessels?

Lymphatic vessels carry lymph from peripheral tissues to the venous system. The lymphatic system transports lymphocytes, is involved in the removal of foreign matter & cell debris by phagocytes & is part of the body's immune system. It also transports fats from the small intestine to the blood.

Lymph capillaries merge to form larger vessels called

Lymphatic vessels, which convey lymph into and out of structures called lymph nodes.

Which of the following is located in the spleen''s white pulp regions?

Lymphocytes

Lymphoid Cells

Lymphocytes are the main cells involved in the immune response Two main varieties: T cells B cells

Kidney cells mostly have

MHC class II

Some cells also display

MHC class II antigens.

Which of the following is found lining the lymphatic sinuses of the lymph nodes?

Macrophages (Macrophages line the sinuses, they process foreign material passing through the sinuses).

Which of the following is NOT a lymphatic organ?

Macrophages are cells, not organs.

Clinical View: Lymphoma

Malignant neoplasm from lymphatic structures Nontender, enlarged lymph node possible night sweats, fever, and weight loss Hodgkin lymphoma affects young adults and people over 60 if caught early, cured by excision, radiation, and chemotherapy Non-Hodgkin lymphoma more common some kinds aggressive, others slow growing

T cells

Manage the immune response Attack and destroy foreign cells (circulate continuously among the blood, lymph nodes, and lymphatic stream)

The activated B cells that do not differentiate into plasma cells remain as

Memory B cells, ready to respond more rapidly and forcefully should the same antigen appear at a future time.

Lymphatic capillaries

Merge to form larger lymph vessels called lymphatic vessels, which convey lymph into and out of structures called lymph nodes. Are the smallest lymph vessels. They are microscopic, closed-ended vessels that absorb interstitial fluid. They are interspersed throughout areolar connective tissue among most blood capillary networks, except those within the red bone marrow and the central nervous system.They are absent within avascular tissues such as epithelia.

Lymph vessels include:

Microscopic, permeable, blind-ended capillaries Lymphatic collecting vessels Trunks and ducts

Structures that house immune system cells

Most found not in the blood but in lymphatic tissue select organs epithelial and mucosal membranes connective tissue

Secondary lymphatic structures

Not involved in lymphocyte formation House lymphocytes and other immune cells Provide site of immune response initiation Include lymph nodes, spleen, tonsils, and lymphatic nodules Include MALT (mucosa-associated lymphatic tissue)

Lymphatic Vessels

One-way system, lymph flows toward the heart Transport leaked plasma proteins and fluids to the cardiovascular system

Isolated areas of lymphoid follicles found in the intestinal mucosa are called

Peyer's Patch

These highly specialized lymph capillaries are found in the intestinal mucosa.

Peyer's Patch which is located in the small intestines

Aggregates of lymphoid nodules located in the wall of the ileum are

Peyer's patches - These prevent bacteria from migrating through the wall of the intestine.

MALT (Mucosa-Associated Lymphoid Tissue)

Peyer's patches of the intestinal wall, lymphoid follicles of the appendix, tonsils of the pharynx and oral cavity, and follicles in the genitourinary and respiratory tract mucosae. They prevent pathogens in these passages from penetrating the mucous membrane lining.

MALT - mucosa-associated lymphatic tissue:

Peyer's patches, tonsils, and the appendix (digestive tract) Lymphoid nodules in the walls of the bronchi (respiratory tract) protects the digestive and respiratory systems from foreign matter

Macrophages then destroy some foreign substances by

Phagocytosis and lymphocytes bring about the destruction of others by immune responses.

3 types of tonsils

Pharyngeal - in posterior wall of nasopharynx when enlarged, termed adenoids Palatine - in posterolateral oral cavity Lingual - along posterior one-third of tongue

B cells

Produce plasma cells, which secrete antibodies Antibodies immobilize antigens

The germinal center in lymph nodes are largely sites of

Proliferating

Immune system

Protects us from infectious agents and harmful substances typically without our awareness Composed of numerous cellular and molecular structures Function together to provide us with immunity Function dependent on specific type of infectious agent

Abscess

Pus must drain out of the body or it accumulates in a confined space, causing this.

Cardinal signs of inflammation

Redness (Erythema) increased blood flow Heat increased blood flow and increased metabolic activity within the area Swelling (edema) increase in fluid loss from capillaries to interstitial space Pain (algesia) stimulation of pain receptors from compression from interstitial fluid chemical irritation by kinins, prostaglandins, microbe substances Loss of function (may occur in severe cases) Acute inflammatory response typically lasts 8-10 days sometimes persists in process of chronic inflammation

The structural framework of lymphoid organs is

Reticular tissue

The lymph vessels are

Right lymphatic duct, Thoracic duct, Cisterna chyli, Lymphatic trucks, Lymphatic vessels, Lymphatic capillary. - Begin as blind-ended lymph capillaries in tissue spaces between cells.

Structures that house immune system cells (continued)

Select organs macrophages also housed in other organs some specifically named based on location e.g., alveolar macrophages of lungs; microglia of brain may be permanent residents, fixed macrophages may migrate through tissues as wandering macrophages

Lymphatic Capillaries

Similar to blood capillaries, with modifications: Very permeable Loosely joined endothelial minivalves Withstand interstitial pressure and remain open

Tonsils

Simplest lymphoid organs; form a ring of lymphatic tissue around the pharynx Location: Palatine tonsils - either side of the posterior end of the oral cavity Lingual tonsils - lie at the base of the tongue Pharyngeal tonsil - posterior wall of the nasopharynx Tubal tonsils - surround the openings of the auditory tubes into the pharynx

spleen functions

Site of lymphocyte proliferation Immune surveillance and response Cleanses the blood Stores breakdown products of RBCs for later reuse Spleen macrophages salvage and store iron for later use by bone marrow Site of fetal erythrocyte production (normally ceases after birth) Stores blood platelets

antigen determinants, or epitopes

Specific portions of antigen molecules, trigger immune responses

immunity

Specific resistance to disease involves the production of a specific lymphocyte or antibody (Ab) against a specific antigen (Ag)

The red pulp area of the spleen are sites of

Splenic sinusoids

Name the vein that each of the two collecting ducts deposit their lymph.

Subclavian vein

Third Line of Defense: Antigens

Substances that bind to a component of adaptive immunity Pathogenic organisms often detected due to their antigens Usually a protein or large polysaccharide Include protein capsid of viruses cell wall of bacteria or fungi bacterial toxins tumor cells with unique abnormal protein

Which cells of the lymph node perform a surveillance role

T- cells

Helper T cells are also called

T4 cells and (TH) cells

resistance

The ability to ward off disease using a number of defenses

antibody titer

The amount of antibody in serum.

allergens

The antigens that induce and allergic reaction

Lymph nodes are densely clustered in

The axillae, The groin and The cervical region

Which area does NOT contain a large collection of lymph nodes?

The brachial area - The extremities do NOT possess large collections of lymph nodes.

immunology

The branch of science that deals with the responses of the body when challenged by antigens

Fever is an abnormally high body temperature in response to invading microorganisms intended to kill off pathogens and other benefits include:

The liver and spleen to sequester iron and zinc (needed by microorganisms) An increase in the metabolic rate, which speeds up tissue repair

What factors are involved in the flow of lymphatic fluid?

The milking action of the skeletal muscles and on pressure changes within the thorax that occur during breathing.

what are the first line of defense against pathogens?

The skin and mucous membranes of the body. Both mechanical and chemical factors are involved

What is the first line of defense against pathogens?

The skin and mucous membranes of the body. Both mechanical and chemical factors are involved.

Interstitial fluid drains into

lymphatic capillaries, thus forming lymph

The lymphoid organs, located in the throat, that defend against invading bacteria coming in through the mouth and nose are

Tonsils (The tonsils form a ring of lymphatic tissue around the entrance to the pharynx.)

Lymphatic tissue and organs are organized into primary and secondary structures. What are the secondary ones?

Tonsils, Lymph nodes (cervical), Lymph nodes (axillary), Spleen, MALT (mucosa-associated lymphatic tissue) in small intestine, Lymph nodes (inguinal)

Lymphatic system

Tonsils, lymph nodes, spleen, and lymphatic vessels Helps immune system defend body against infectious agents Enlargement in lymphatic structures sign that organs actively engaged in defending the body Transports and houses lymphocytes and other immune cells Returns excess fluid to blood to maintain fluid balance lymph, fluid transported within the lymph vessels

Distinguish an afferent lymphatic vessel.

Toward (Lymph Node)

Elephantiasis

Typically a tropical disease in which the lymphatics (particularly those of the lower limbs and scrotum) become clogged with parasitic roundworms, an infectious condition called filariasis. Swelling (due to edema) reaches enormous proportions.

Metastasis

Wandering cancerous cells may establish secondary tumors that develop in other locations within the body, a process referred to as..

The third line of defense Inflammation. When does inflammation occur?

When cells are damaged by microbes, physical agents, or chemical agents. The injury may be viewed as a form of stress.

clone of effector cells

a population of identical cells that can recognize the same antigen and carry out some aspect of the immune attack

Lymph flows are also aided by

lymphatic vessel valves which prevent backflow of lymph

The cells in lymphoid tissues include

lymphocytes (cells called T cells or B cells), plasma cells (antibody producing offspring of B cells), macrophages and dendritic cells (cells that capture antigens and initlate an immune response) and reticular cells that form the lymphoid tissue storma.

The spleen provides

a site for lymphocyte proliferation and immune function, and destroys aged or defective red blood cells and bloodborne pathogens. It also stores and releases the breakdown products of hemoglobin as necessary, stores platelets and acts as a hematopoetic site in the fetus.

Nonspecific resistance refers to

a wide variety of the body responses against a wide range of pathogens (disease-producing organisms) and their toxins.

Which anatomical characteristic ensures that the flow of lymph through lymph node is slow? Why is this desirable?

a. The anatomical characteristic that ensures slow passage of lymph through a lymph node is the fact that there are fewer efferent vessels draining the node than afferent vessels feeding it. b. This feature is desirable to allow time for the lymphocytes and macrophages to perform their protective functions.

large clusters of lymph nodes are found near the body surface in all of the following areas

a. axillary region b. inguinal region c.cervical region

Name 2 primary lymphatic structures and tell where there location is and their function

a. red bone marrow- spaces in spongy bone within certain bones, function- formation of all formed elements b. thymus-Superior mediastinum ( in adults); anterior and superior mediastinum (in children) function- is site of T lymphocyte maturation and differentiation

All the following statements are true about lymphatic tissue

a. they house lymphocytes and macrophages b. they are largely composed of reticular connective tissue c. they are the site of lymphocyte proliferation

Pus must drain out of the body or it accumulates in a confined space, causing an

abscess

The lymphatic capillaries are typically larger in diameter than blood capillaries, lack a basement membrane, and have overlapping endothelial cells. What do theses overlapping endothelial cells do?

act as one-way flaps to allow fluid to enter the lymphatic capillary, but prevent its loss.

APC's include

macrophages

(Self-recognition and Immunological Tolerance) Forms of immunotherapy in use include

adoptive cellular immunotherapy, cytokine therapy (Interleukin-1 and Interleukin-2), and antibody therapy

(Circulation in the Lymph Nodes) Lymph enters the lymph nodes via

afferent lymphatic vessels and exits via efferent vessels. There are fewer efferent vessels therefore, lymph flow stagnates within the lymph node, allowing time for its cleansing.

Lymph enters nodes through

afferent lymphatic vessels, is filtered to remove damaged cells and microorganisms, and exits through efferent lymphatic vessels.

Antimicrobial substances, such as transferrins, interferon, complement, and properdin work

against colonization by viruses and bacteria and provide a second line of defense should microbes penetrate the skin and mucous membranes.

Inflammation

aids in disposal of microbes, toxins, or foreign material at the site of the injury and prepares the site for tissue repair. the response to tissue damage, 4 symptoms- redness , pain ,heat, swelling

Chemical factors/ Lysozyme is?

an enzyme component of sweat which also has antimicrobial properties.

T cells and B cells protect the body against

antigens

Antibody - mediated (humoral) immunity (AMI) works against

antigens dissolved in body fluids and extracellular pathogens, primarily bacteria, that multiply in body fluids but rarely enter body cells.

exogenous antigens

antigens formed outside the body

B cells can recognize and bind to

antigens in extracellular fluid

endogenous antigens

antigens that were synthesized in a body cell (e.g. viral proteins from virus-infected cells).

The U.S. governments's definition of AIDS as simplified in 1991 to include

anyone infected with HIV and having a CD4 lymphocyte count under 200/mm3 of blood (normal CD4 count is approximately 1200/mm3)

Antigen

anything the body perceives as foreign Bacteria and their toxins; viruses Mismatched RBCs or cancer cells

This structure attached to the cecum is in an ideal place to destroy bacteria before it migrates into the large intestine.

appendix This structure extends from the cecum.

guard mucosal surfaces include

appendix follicles, the tonsils , peyer's patches

Antigens (Ags)

are chemical substances that are recognized as foreign by antigen receptors when introduced into the body.

Tonsils

are multiple aggregations of large lymphatic tissue in the body and is found a mucous membrane at the junction of an oral cavity and the pharynx. Tonsils are our nodules and we have 3 pairs of tonsils. B cells hang out in tonsils.

Memory T cells

are programmed to recognize the original invading antigen, allowing initiation of a much swifter reaction should the pathogen invade the body at a later date.

Monoclonal antibodies (MAbs)

are pure antibodies produced by fusing a B cell with a tumor cell that is capable of proliferating endlessly. The resulting cell is called a hybridoma.

Suppressor T (Ts) cells

are thought to be a class of T cells distinct from TH and Tc cells. They appear to downregulate immune responses by producing cytokines such as TGF-B, which inhibits proliferation of B cells and T cells. (Make us down regulate/surpress B and T cell cloning)

Infectious agents Five major categories:

bacteria viruses fungi protozoans multicellular parasites

Lymphatic vessels begin as

blind-ended lymph capillaries in tissue spaces between cells

The only means of preventing AIDS is to

block transmission of the virus, including during intercourse, use of sterile hypodermic needles, and avoidance of pregnancy in HIV-infected women.

Although HIV has been isolated from several body fluids, the only documented transmissions are by way of

blood, semen, vaginal secretions, and breast milk from an infected nursing mother.

Tissue rejection of a transplanted tissue or organ involves

both cell-mediated and antibody-mediate immune responses. May be minimized by closely matching the MGC (HLA) antigens between donor and recipient and may often be overcome with immunosuppressive drugs (such as cyclosporine)

phagocytes participate in?

both nonspecific defenses and in immunity

(Self-recognition and Immunological Tolerance) T cells undergo

both positive and negative selection to ensure that they can recognize self-MHC antigens (self-recognition) and that they do not react to other self-proteins (tolerance). Negative selection involves both deletion and energy.

Often a pathogen provokes

both types of immune responses (Cell - mediated (CMI) and Antibody - mediated (humoral) immunity (AMI)

What lymphatic structure absorbs excess tissue fluid?

capillary - These vessels have pressure sensitive valves.

During inflammation lymph capillaries can absorb

cell debris, pathogens and cancer cells

Monoclonal antibodies (MAbs) antibodies are important in

measuring levels of a drug in a patient's blood and in the diagnosis of pregnancy, allergies, and diseases such as hepatitis, rabies, and some sexually transmitted diseases.

Plasma cells are concentrated in which portion of the lymph node

medulla

(Immunological Memory) Immunization against certain microbes is possible because

memory B cells and memory T cells remain after the primary response to an antigen.

The inflammatory responses serves a protective and defensive role by eliminating

microbes, toxins, or foreign material from the site of injury, preventing their spread to other organs, and preparing the site for tissue repair. It is an attempt to restore tissue homeostasis.

four phases of phagocytosis are?

chemotaxis, adherence, ingestion, and killing

The sac-like initial portion of the thoracic duct that receives lymph from the legs and the intestinal tract is the:

cisterna chyli

What lymphatic structure forms from the merging of the intestinal and lumbar trunks?

cisterna chyli - This structure is an enlarged collecting sac.

The pressure exerted by lymph after it enters the lymphatic capillary forces the endothelial cells of these vessel to _____

close

A group of about 20 proteins present in blood plasma and on cell membranes comprises the

complement system; when activated these proteins "complement" or enhance certain immune, allergic, and inflammatory reactions.

Body cells infected with viruses produce proteins

complement system; when activated these proteins "complement" or enhance certain immune, allergic, and inflammatory reactions.

Lymphatic system

consists of a fluid called lymph flowing within lymphatic vessels (lymphatics), several structures and organs that contain lymphatic tissue, and bone marrow, which is the site of lymphocyte production. (reclaiming system)

Cytotoxic T (Tc) cells or T8 cells

develop from T cells that display CD8 protein and recognize antigen fragments associated with MHC-1 molecules. (On the #8 position - first responder to APC intruder)

The lymphatic (lymphoid) tissue-containing components of the lymphatic system are

diffuse lymphatic tissue, lymphatic nodules, and lymphatic organs (lymph nodes, spleen, and thymus gland).

Cytotoxic T cells, TC cells, or killer T cells, are the only T cells that can

directly attack and kill other cells

What is the role of T cells?

directly attack virus-infected tissue cells, some help activate the B cells and cytotoxic T cells, and others can inhibit the immune response. They provide cellular immunity.

Pathogens

disease producing organisms

Helper T (TH) cells, or T4 cells

display CD4 protein, recognize antigen fragments associated with MHC-II molecules, and secrete several cytokines, most importantly, interleukin-2, which acts as a costimulator for other helper T cells, cytotoxic T cells, and B cells.

Lymphatic system functions to

drain interstitial flud, return leaked plasma proteins to the blood, transport dietary fats, and protect against invasion by nonspecific defenses and specific immune responses.

Lymph nodes are

encapsulated oval structures located along lymphatic vessels. They are scattered throughout the body, usually in groups.

Most cells of the body can process and present

endogenous antigens

Cells called antigen-presenting cells (APC's) process

exogenous antigens and present the together with MHC molecules to T cells.

Reticular cells

fibroblast-like cells that produce a stroma, or network, that supports other cell types in lymphoid organs

Each lymph node has a

fibrous capsule, a cortex, and a medulla. The cortex contains mostly lymphocytes, which act in immune responses; the medulla contains macrophages, which engulf and destroy viruses, bacteria, and other foreign debris, as well as lymphocytes and plasma cells.

Trabeculae:

fibrous partitions made of collagen fibers that extend from capsule into interior of lymph node

Which of the following is a function only of the lymph nodes and not the other lymphoid organs?

filter lymph

What are the two major functions of the lymph nodes?

filtering and protection

T cells, however can only recognize

fragments of antigenic proteins that first have been processed and blended in association with MHC self-antigens (can only identify hybrid).

How can a ulcer result?

from a prolonged inflammatory response to a continuously injured tissue (e.g. in the lining of the stomach or the tissues of the legs in persons with poor circulation to their extremities).

The passage of lymph is

from arteries and blood capillaries (blood) to interstitial spaces (interstitial fluid) to lymph capillaries (lymph) to lymphatic vessels to lymph trucks to the thoracic duct or right lymphatic duct to the subclavian veins (blood).

What is the passage flow of lymph?

from lymph capillaries to lymphatic vessels to lymph trunks to the thoracic duct or right lymphatic duct to the subclavien veins.

Antigen receptors exhibit great diversity due to

genetic recombination

Therapy for Autoimmune disease typically involves

giving drugs to suppress immune responses, leaving the person prone to opportunistic infections Another treatment in the testing stage is oral antigen therapy

What are the two categories of Phagocytes?

granulocytes (microphages - neturophils and eosinophils) and macrophages (fixed and wandering)

Allergy localized anaphylactic reactions include

hay fever, asthma, eczema, and hives; accute anaphylaxis is a severe reaction with systemic affects. Allergies most common plant based.

Among the substances that contribute to vasodilation, increased permeability, and other aspects of the inflammatory response are:

histamine, kinins, prostaglandins (PGs), leukotriences (LTs), and complement

A retrovirus is called

human immunodeficiency virus (HIV)

Chemical factors/ Areolar (loose) connective tissue contains?

hyaluronic acid, which helps to contain infections to a localized area

Without TH, there is no

immune response

Antigens are both

immunogenic and reactive

Monoclonal antibodies (MAbs) have also been used

in early detection of cancer and assessment of extent of metastasis; they may be useful in preparing vaccines to counteract transplant rejection, to treat autoimmune response, ad perhaps to treat AIDS.

Where is the spleen found

in the left hypochondriac region between the fundus of the stomach and the diaphragm.

Where do T cells complete their maturation and develop immunocompetence?

in the thymus

The driving force to move fluid into the lymphatic capillaries is an

increase in hydrostatic pressure within the interstitial space

(Self-recognition and Immunological Tolerance) Tumor immunotherapy

inducing the immune system to mount an attach cancer, is becoming a viable means of treating some types of human cancer.

Note three areas where lymph nodes are densely clustered:

inguinal, axillary, and cervical regions of the body.

Mechanical defenses include the

intact epidermis layer of the skin, mucous membranes, the lacrimal apparatus, saliva, mucus, cilia, the epiglottis, and the flow of urine. Defecation and vomiting also may be considered mechanical process that expel microbes.

Second line of defense

internal processes of innate immunity Cells: neutrophils, macrophages, NK cells Chemicals: interferon and complement Inflammation Fever

Lymph

interstitial fluid once it has entered lymphatic vessels

The passage of lymph is from arteries and blood capillaries (blood) to....

interstitial spaces (interstitial fluid) to lymph capillaries (lymph) to lymphatic vessels to lymph trunks to the thoracic duct or right lymphatic duct to the subclavian veins (blood).

Cell - mediated (CMI) is particularly effective against

intracellular pathogens, such as fungi, parasites, and viruses; some cancer cells; and foreign tissue transplants; thus, CMI always involves cells attacking cells

opportunistic infections

invasion of normally harmless microorganisms that now proliferate wildly because of the defective immune system

Primary Lymphatic structure

involved in the formation and maturation of lymphocytes. Both the red bone marrow and thymus are considered primary lymphatic structures.

Systemic lupus erythematosus (SLE or Lupus)

is a inflammatory disease of connective tissue, occurring mostly in young women.

antibody (Ab)

is a protein that can combine specifically with the antigenic determinant on the antigen that triggered its production. It's a hat maker.

Severe combined immunodeficiency

is a rare disease in which both B cells and T cells are missing or unable to provide immunity. It may be genetic (Boy in Plastic bubble)

Hodgkin's disease (HD)

is a usually curable malignant disorder, generally arising in the lymph nodes

Cytotoxic T cells leave the lymphoid and

migrate to the site of invasion, infection, or tumor formation. They recognize and attach to the target cell that bears the same antigen as the one that stimulated their activation and proliferation. They then eliminate invaders cells by secreting perforin, which causes cytolysis or lymphotoxin (LT) which causes fragmentatin of the DNA of a target cell.

antigen receptors

molecules capable of recognizing specific antigens

With advancing age, the immune system functions less effectively. Individuals become

more susceptible to infections and malignancies, response to vaccines is decreased, and more autoantibodies are produced. Cellular and humoral responses also diminish

Entry of lymph into the lymphatic capillaries is promoted by what?

one-way minivalves formed by overlapping endothelial cells and greater fluid pressure in the interstitial space

Systemic lupus erythematosus (SLE or Lupus) symptoms include

painful joints slight fever, fatigue, mouth ulcers, weight loss, enlarged lymph nodes and spleen, photosensitivity, rapid loss of large amounts of scalp hair, and sometimes an eruption across the bridge of the nose and cheeks called a "butterfly rash.". Other skin lesions may occur with blistering and ulceration; the most serious complications involve inflammation of the kidney, liver spleen, lungs, heart, and the central nervous system.

What lymphatic structures trap bacteria in the posterior oral mucosa?

palatine tonsils - These tonsils are most often infected.

Nonspecific resistance refers to a wide variety of body responses against a wide range of

pathogens (disease-producing organisms) and their toxins.

Macrophages

phagocytize foreign substances and help activate T cells

Steps in processing and presenting an exogenous antigen by an APC are:

phagocytosis or endocytosis of the antigen, partial digestion, fusion of vesicles, binding of peptide fragments to MHC-II molecules, and exocytosis.

An activated B cell develops into a clone of antibody-producing

plasma cells

Delayed - type hypersensitivity T Cells

produce cyctokines and are important in hypersensitivity and are important in hypersensitivity (allergic) reactions. Responds to plant or fur dander

Chemical factors/ The skin

produces sebum, which has a low pH due to the presence of unsaturated fatty acids and lactic acid

Lymph nodes are the site of

proliferation of plasma cells and T cells. (T cells can destroy intruders, B cells identify intruders, they become antibodies)

(Immunological Memory) The secondary response provides

protection should the same microbe enter the body again. There is rapid proliferation of memory cells, resulting in a far greater antibody titer than during a primary response.

Antibodies

proteins that bind to specific antigens and mark them for destruction.

For an immune response to occur, B and T cells must

recognize that a foreign antigen is present.

In a cell-mediated immune response, an antigen is

recognized (bound), a small number of specific T cells proliferate and differentiate into a clone of effector cells, and the antigen (intruder is eliminated).

All cells display MHC class I antigens except for

red blood cells

Almost all cells have antigens except for

red blood cells

After a splenectomy what other structures take over functions

red bone marrow and the liver

Inflammation is usually characterized by these four symptoms.

redness, pain, heat and swelling. Loss of function my be a fifth symptom, depending on the site and extent of the injury.

Cell - mediated (CMI)

refers to destruction of antigens by T cell

Antibody - mediated (humoral) immunity (AMI)

refers to destruction of antigens by antibodies

In Systemic lupus erythematosus (SLE or Lupus), damage to blood vessel walls results in the

release of chemicals that mediate the inflammatory response; the blood vessel damage can be present in virtually every body system.

Chemical factors/ Gastric juice

renders the stomach nearly sterile since its low pH (1.5-3.0) kills many bacteria and destroys most of their toxins; vaginal secretions are also slightly acidic.

Autoimmune disease (autoimmunity)

results when the body does not recognize "self" antigens and produces antibodies against them.

These cells produce the stroma of the lymph organs

reticular cells

The structural framework of lymphoid tissue is offered by

reticular connective tissue. This tissue dominates in all lymphoid organs EXCEPT the thymus.

A major function of the lymphatic system is

return of tissue fluid to the cardiovascular system. (About 3 L of fluid are picked up each day.)

Human Autoimmune disease include

rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), thyroidits, rheumatic fever, glomerulonephritis, encephalomyelitis, hemolytic and pernicious anemias, Addison'ts disease, Graves' disease, insulin-dependent (type 1) diabetes mellitus, myasthenia gravis, and multiple selerosis (MS)

Before T cells leave the thymus or B cells leave the bone marrow, they acquire

several distinctive surface proteins; some function as antigen receptors

First line of defense

skin and mucosal membrane

Chronic fatigue syndrome (CFS) symptoms are

sore throat, headache, muscular aches, fever and chills, fatigue, joint pain, neuropsychological complaints, sleep disturbances, and development of the initial sysmptoms over a few hours to a few days. Its cause is not known

lymphatic tissue

specialized reticular tissue containing large numbers of lymphocytes.

Dendritic cells

spiny-looking cells with functions similar to macrophages - nearly encapsulate the follicles

The largest lymph organ in the body is the

spleen ( largest mass of lymphatic tissue)

B- cells are found in the

spleen, tonsils, and appendix

Both T and B cells derive from

stem cells in bone marrow

Peptide fragments from foreign antigen help

stimulate MHC molecules

immunocompetence

the ability to carry out immune responses if properly stimulated

After lymph enters the lymphatic capillaries, it continues to flow into increasinly larger lymphatic vessels, trucks, and ducts. Ultimately, the lymph empties into ___ ____ ____.

the blood circulation

chemotaxis

the chemical attraction of phagocytes to a particular location

Skin and mucous membranes of the body are

the first line of defense against pathogens. Both mechanical and chemical factors are involved.

sentinel node

the first node that receives lymph drainage from a body area suspected of being cancerous. When examined for presense of cancer cells, this node given the best indication of whether metastasis through the lymphatic vessels has occurred.

The third line of defense is phagocytosis

the ingestion and destruction of microbes of any foreign particulate matter by cells called phagocytes.

The spleen is

the largest mass of lymphatic tissue in the body

spleen

the largest mass of lymphatic tissue in the body and is found in the left hypochondriac region between the fundus of the stomach and the diaphragm. It is a site of B cell proliferation into plasma cells, phagocytosis of bacteria and worn out or damaged red blood cells and platelets, and storage of blood.

Lymph flows as a result of

the milking action of skeletal muscle contractions and respiratory movements.

Other complications for AIDS victims include

tuberculosis, persistent diarrhea, leukoplakia (whitish patches on mucous membranes) cytomegalovirs (leading to blindness) disseminated herpes simplex, and severe shingles, among other bacterial and fungal infections.

There are four basic types of hypersensitivity reactions: The first three involve antibodies, the last involves T cells.

type I (anaphylaxis), type II (cytotoxic), type III (immune complex) and type IV (cell-mediated)

Major histocompatibility complex (MHC) antigens (also called human leucocyte associated, or HLA, antigens) are

unique to each person's body cells. These self-antigens aid in the detection of foreign invaders. We have about 272 make up MHC class I antigens.

Who doesn't filter lymph?

unlike lymph nodes, the spleen, thymus, tonsils, and Peyer's patches do not filter lymph. Most lymphoid organs contain both macrophages and lymphocytes.

Chronic fatigue syndrome (CFS)

usually occurs in young adults, primarily females. It is characterized by extreme fatigue that impairs normal activities for at least six months and the absence of known disease that might produce similar symptoms.

The stages of the inflammatory response are:

vasodilation (increase in diameter of blood vessels) and increased permeability of the blood vessels, phagocyte migration, and repair.

The components of lymph include

water, dissolved solutes (e.g., ions), a small amount of protein (approximately 100 to 200 grams that leaked into the interstitial space during capillary exchange), sometimes foreign material that includes both cell debris and pathogens, and perhaps metastasized cancer cells.

Lymphatic System

is composed of lymph vessel and lymphatic tissues and organs. Consists of a fluid called lymph flowing within lymphatic vessels (lymphatics), several structures and organs that contain lymphatic tissue and bone marrow. It functions to drain interstitial fluid, return leaked plasma proteins to the blood, transport dietary fats, and protect against invasion by nonspecific defenses and specific immune responses.

Immunological Memory

is due to the presence of long-lived antibodies and very long-lived lymphocytes that arise during proliferation and differentiation of antigen-stimulated B and T cells.

Hypersensitivity (allergy)

is overreactivity to an antigen.

Phagocytosis

is the ingestion of microbes or any foreign particulate matter by cells.

Thoracic duct

is the main collecting duct of the lymphatic system and receives lymph from the left side of the head, neck, and chest, the left upper extremity, and the entire body below the ribs. (The largest duct)

bone marrow

is the site of lymphocyte production

Fever

is usually caused by infection from bacteria (and their toxins) and viruses. The high body temperature inhibits some microbial growth and speeds up body reactions that aid repair.

The third line of defense is Fever

is usually caused by infection from bacteria (and their toxins) and viruses. The high body temperature inhibits some microbial growth and speeds up body reactions that aid repair.

Peyer's patches

isolated clusters of lymphoid tissue, similar to tonsils Found in the wall of the distal portion of the small intestine Similar structures are found in the appendix

Susceptibility

lack of resistance

Antigens are

large, complex molecules - most often proteins, but sometimes nucleoproteins, lipoproteins, glycoproteins, and certain large polysaccharides

Thymus gland

lies between the sternum and the heart and functions in immunity as the site of T cell maturation

Acquired Immune deficiency syndrome (AIDS)

lowers the body's immunity by decreasing the number of helper T cells; the result is progressive collapse of the immune system, making the person susceptible to opportunistic infections

The right lymphatic duct drains

lymph from the upper right side of the body

Lymphatic tissue

lymph nodes, spleen, tonsils, MALT, lymphatic nodules many T- and B-lymphocytes, macrophages, NK cells housed here

Cytotoxic T cells, TC cells, or killer T cells, are the only T cells that can directly attack and kill other cells. They circulate throughout the body in search of body cells that display the antigen to which they have been sensitized. Their targets include:

• Virus-infected cells • Cells with intracellular bacteria or parasites • Cancer cells • Foreign cells from blood transfusions or transplants

Foreign substances filtered by the lymph nodes are

trapped by nodal reticular fibers

How do lymphatic capillaries differ from blood capillaries?

1). Blood capillaries carry blood from small arterioles to small venules. 2). Lymphatic capillaries carry lymphatic fluid from tissue to lymphatic venules. 3). In structure, lymph capillaries are slightly bigger in diameter but have thinner walls than blood capillaries

Name Disorders: Homeostatic Imbalaces

1) Acquired Immune deficiency syndrome (AIDS), 2) Autoimmune disease (autoimmunity) 3) Systemic lupus erythematosus (SLE or Lupus) 4) Chronic fatigue syndrome (CFS) 5) Severe combined immunodeficiency 6) Hypersensitivity (allergy) 7) Tissue rejection of a transplanted tissue or organ 8) Hodgkin's disease (HD)

The 3rd line of defense is

1) phagocytosis, the ingestion and destruction of microbes of any foreign particulate matter by cells called phagocytes, and 2). inflammation and 3) fever

Hodgkin's lymphoma

A malignancy of lymphoid tissue: symptoms include swollen, nonpainful lymph nodes, fatigue, and often intermittent fever and night sweats. Characterized by presence of giant malignantly transformed B cells called Reed-Sternberg cells. Infection with Epstein-Barr virus (see mononucleosis) and genetic susceptibility appear to be predisposing factors. Treated with chemotherapy and radiation, high cure rate.

Lymphatic system consists of 2 semi-independent parts:

A network of lymphatic vessels Lymphoid tissues and organs scattered throughout the body Returns lymph (interstitial fluid and leaked plasma proteins) back to blood

Which of the following best describes the arrangement of lymphatic vessels?

A one-way system of vessels beginning with blind-ended lymphatic capillaries (The lymphatic vessels form a one-way system in which lymph flows only toward the heart. It begins as blind-ended capillaries.)

Mononucleosis

A viral disease common in adolescents and young adults; symptoms include fatigue, fever, sore throat, and swollen lymph nodes. Caused by the Epstein-Barr virus which is transmitted in saliva ("kissing disease") and specifically attacks B lymphocytes. This attack leads to a massive activation of T lymphocytes, which in turn attack the virus-infected B cells. Large numbers of oversized T lymphocytes circulate in the blood stream. (these lymphocytes were originally misidentified as monocytes) Usually lasts four to six weeks.

lymphatic capillaries are absent from

A. THE CENTRAL NERVOUS SYSTEM B. BONES C.TEETH

Drugs currently in use or in clinical trials that may slow the progress of symptoms of HIV include

AZT (azidothymidine, ore Restrovir) ddl (dideoxynosine), and ddC(dideoxycytidine)

What frequently causes a ruptured spleen?

Abdominal trauma, which due to its capacity for blood storage, may cause severe intraperitoneal hemorrhage and shock

Clinical View: Hypersensitivities

Abnormal and exaggerated response of immune system to antigen Acute hypersensitivities occurring within seconds Subacute hypersensitivities occurring within 1-3 hours both involve humoral immunity Delayed hypersensitivities within 1 to 3 days involve cell-mediated immunity Acute hypersensitivity, allergy overreaction of immune system noninfectious substance, allergen e.g., pollen, latex, peanuts may cause multiple symptoms runny nose and watery eyes red welts and itchy skin (hives) labored breathing and coughing (allergic asthma) vomiting and diarrhea systemic vasodilation and inflammation may go into anaphylactic shock

What is the function of B cells in the immune response?

B cells differentiate into plasma cells that secrete antibodies. Antibodies are proteins that bind to specific antigens and mark them for destruction. They provide humoral immunity.

Clinical View: HIV and AIDS

Acquired immunodeficiency syndrome life-threatening condition Result of human immunodefiency virus infects and destroys helper T-lymphocytes numbers dropping to low numbers resides in body fluids of infected individuals can be transmitted by intercourse, needle sharing, breastfeeding Prevention through safe sex HIV tests looking for HIV antibodies in the blood Becomes AIDS when helper T-lymphocytes drop below certain level individuals prey to opportunistic infections may have CNS complications No cure for HIV treatments alleviating symptoms and helping prevent spread of HIV

Lymph node components

Afferent lymphatic vessels bring lymph into lobe Efferent vessel drains node originates at involuted portion of node, hilum Capsule enclosing node sends internal extension into it, trabeculae subdivide node into compartments

Pus

After phagocytes engulf damaged tissue and microbes, they eventually die, forming a pocket of dead phagocytes and damaged tissue and fluid

In lymphatic capillaries The minivalves function as one-way gates that:

Allow interstitial fluid to enter lymph capillaries Do not allow lymph to escape from the capillaries

Thymus gland

An endocrine gland located in the upper mediastinum Lies between the sternum and the heart, that assists the body with the immune function and the development of antibodies. As part of the immune response it secretes a hormone, thymosin, that changes lymphocytes to T cells

Lymphadenopathy

Any disease of the lymph nodes

Lymphoma

Any neoplasm (tumor) of the lymphoid tissue, whether benign or malignant.

Cytokines

Are small protein hormones needed for many normal cell functions. The hormones are loitering inside cell membrane. Some of them regulate immune responses. Respond to second messenger.

The spleen is a site of

B cell proliferation into plasma cells, phagocytosis of bacteria and worn-out or damaged red blood cells and platelets, and storage of blood.

Compare and contrast blood, interstitial fluid, and lymph.

Blood, the carrier of nutrients, wastes, and gases, circulates within blood vessels through the body, exchanging materials with the interstitial fluid. Interstitial fluid, formed by filtration from blood, is the fluid surrounding body cells in the tissue spaces and is essential to proteinless plasma. Lymph is the protein-containing fluid that enters the lymphatic capillaries (from the tissue spaces); hence, its composition is the same as that of the interstitial fluid.

Interferons (IFNs)

Body cells infected with viruses produce proteins

Name four tissues that do not contain lymphatic capillaries.

CNS, Splenic pulp, Bone marrow , Avascular tissues

Which sequence best describes the flow of lymph through the lymphatic system?

Capillaries - vessels - trunks - ducts ------- (Capillaries pick up lymph and ducts return it to the cardiovascular system).

What are the two types of (immunity) Immune responses

Cell - mediated (CMI) and Antibody - mediated (humoral) immunity (AMI)

Third Line of Defense: Two branches of immunity

Cell-mediated immunity immune response involving T-lymphocytes Humoral immunity immune response involving B-lymphocytes develop into plasma cells to release antibodies

Lymph and Lymph Vessels: Lymph and Lymphatic Capillaries

Characteristics of Lymph 15% of fluid entering interstitial spaces not reabsorbed into capillaries about 3 liters daily Moves passively into lymphatic capillaries due to pressure gradient Termed lymph once inside lymph vessels Components: water, dissolved solutes, and small amount of protein sometimes cell debris, pathogens, or metastasized cancer cells

Helper T cells are regulatory cells that play a central role in the immune response by doing the following:

Chemically or directly stimulate proliferation of other T cells and Stimulate B cells that have already become bound to antigen

Anchoring filaments

Collagen fiber which attach the endothelial cells of lymph capillaries to the surrounding tissue structures so that any increase in interstitial fluid volume opens the minivalves (loose connections between endothelial cells), rather than causing the lymph capillaries to collapse.

Structures that house immune system cells (continued)

Connective tissue mast cells located here typically in close proximity to small blood vessels abundant in dermis abundant in mucosa of respiratory, digestive, urogenital tracts also found in connective tissue of organs e.g., endomysium ensheathing muscle fibers

Lymph Nodes 2 basic functions

Filtration - macrophages destroy microorganisms and debris Immune system activation - monitor for antigens and mount an attack against them

Peyer's patches and the appendix:

Destroy bacteria, preventing them from breaching the intestinal wall Generate "memory" lymphocytes for long-term immunity

Second Line of Defenses: Cells Natural killer cells (Kiss of Death)

Destroy wide variety of unwanted cells virus- and bacteria-infected cells, tumor cells, cells of transplanted tissue Formed in bone marrow and circulate in blood Accumulate in secondary lymphatic structures Patrol the body detecting unhealthy cells termed immune surveillance Destroy unhealthy cells by releasing cytotoxic chemicals include perforin, forming transmembrane pore in unwanted cells include granzymes, initiating apoptosis Apoptosis, form of cellular death

Lymphangiography

Diagnostic procedure in which the lymphatic vessels are injected with radiopaque dye and then visualized with X rays.

What is cisterna chyli?

Enlarged terminus of the thoracic duct that receives lymph from the digestive viscera.

splenomegaly

Enlargement of the spleen due to accumulation of infectious microorganisms, typically caused by septicemia, mononucleosis, malaria, or leukemia.

Which of the following are NOT found in a lymph node?

Eosinophils are a type of leukocyte found in the blood.

Structures that house immune system cells (continued)

Epithelial layers of skin and mucosal membranes dendritic cells here derived from monocytes engulf pathogens in skin and mucosal membranes migrate to lymph node through lymph vessels

Distinguish efferent lymphatic vessel.

Exit (Lymphatic Trunk)

Second Line of Defenses: Chemicals Interferons

Group of antimicrobial protein Class of cytokines released from leukocytes, fibroblasts Non-specific defense mechanism against viral spread Released from virus-infected cell Binds receptors of neighboring cells prevent them from becoming infected triggers synthesis of enzymes destroying viral RNA or DNA triggers synthesis of enzymes that inhibit synthesis of viral proteins Stimulates macrophages and NK cells stimulates to destroy virus-infected cells prevents them from becoming infected triggers synthesis

based on chemistry and structure, antibodies are grouped into five principal classes, each with specific biological roles name them...

IgG, IgA, IgM, IgD, and IgE

Second Line of Defenses: Inflammation

Immediate, local, nonspecific response Occurs in vascularized tissue against variety of stimuli e.g., response to scratch of skin, bee sting e.g., overuse of body structure Major effector response of innate immunity Helps eliminate most infectious agents from body

natural killer (NK)

In addition to cells and T cells, another population of lymphocytes have the ability to kill a wide variety of infectious microbes plus certain spontaneously arising tumor cells; the mechanisms of action and target recognition are poorly understood.

Non-Hodgkin's lymphoma

Includes all cancers of lymphoid tissues except Hodgkin's lymphoma. Involves uncontrolled multiplication and metastasis of undifferentiated lymphocytes, with swelling of the lymph nodes, spleen, and Peyer's patches; other organs may eventually become involved. The seventh most common cancer. A rapid progressing type, which primarily affects young people, grows quickly but responds to chemotherapy' up to a 75% remission rate. A slowly progressing type, which affects the elderly, resists chemotherapy and so is often fatal.

Tonsillitis

Inflammation of the tonsils, typically due to bacterial infection. Tonsils become red, swollen, and sore.

Adaptive Immunity: Third Line of Defense

Initiated upon entry of foreign substance Takes longer to respond than innate immunity Contact with antigen causes lymphocyte to proliferate and form specialized "army" Lymphocytes and products released collectively termed immune response

Fluid enters the lymhphatic system directly from the

Interstitial space

Primary lymphatic structures

Involved in formation and maturation of lymphocytes Red bone marrow and thymus

The Thymus

Is the first lymphoid organ to develop bi-lobed organ (2). In children it is quiet large 30-50- grams, continuous to grow until puberty. Thymic lobed with connective tissue CAPSULE, fibrous extensions of the capsule, called TRABECULAE, subdivide the THYMIC lobes into LOBULES,. Each lobule is arranged into an outer CORTEX, and inner MEDULLA.

Lymph

Is the fluid transported within lymph vessels.

Which statement is true of the thoracic duct?

It drains the lymph from the entire left side of the body and the right abdomen and leg.(The thoracic duct drains its lymph at the junction of the left internal jugular and subclavian veins.)

Which statement describes the lymphatic system''s role in relation to the cardiovascular system?

It maintains blood volume and hence, pressure. (As much as 3 liters of lymph must be returned to the blood volume each day.)

List the six primary body regions drained by lymphatic trunks.

Jugular trunk, Bronchomediastinal trunk, Intercostal trunk, Subclavian trunk, Intestinal trunk, Lumbar trunk

AIDS victims frequently develop

Kaposi's sarcoma (KS) and Pneumocystic carinii pneumonia (PCP).

What lymphatic structure absorbs lipids in the intestine?

Lacteals are located in the intestinal villi.

Which of the following statements is true when comparing large lymphatic vessels to larger veins of the circulatory system?

Large lymphatic vessels have the same three layers, but are thinner and have more valves. (The larger lymphatic collecting vessels have the same three tunics as veins, but the collecting vessels are thinner-walled, and have more internal valves.)

Lymphatic Vessels

Larger structures formed from lymphatic capillaries Superficial vessels positioned adjacent to superficial veins Deep vessels next to deep arteries and veins Have all three vessel tunics (intima, media, externa) Have valves within their lumen required to prevent lymph from pooling in vessel prevent lymph backflow in low-pressure system (develop from lymph sacs, which develop from veins. Thus, they are derived from mesoderm.)

Circulation in the Lymph Nodes

Lymph enters via afferent lymphatic vessels It then enters a large subcapsular sinus and travels into smaller sinuses It meanders through these sinuses and exits the node at the hilus via efferent vessels Because there are fewer efferent vessels, lymph stagnates somewhat in the node This allows lymphocytes and macrophages time to carry out protective functions

one way system

Lymph flows to the heart

What is lymph?

Lymph is a clear to yellowish watery fluid which is found throughout the body. It circulates through body tissues picking up fats, bacteria, and other unwanted materials, filtering these substances out through the lymphatic system; a thin coagulable fluid (similar to plasma but) containing white blood cells (lymphocytes) and chyle

Which of the following make up the principle lymphoid organs in the body?

Lymph nodes (The principle lymphoid organs in the body are the lymph nodes, which cluster along the lymphatic vessels of the body.)

Name the 4 secondary structures

Lymph nodes, tonsils, spleen, MALT

Trace the flow of lymph from interstitial tissues to the bloodstream.

Lymphatic capillaries > Afferent lymphatic vessels > Lymph nodes > Efferent Lymphatic vessels > Lymphatic trunks > Collecting Duct > Subclavian Veins

In addition to lymphoid function, this organ holds a reservoir of platelets.

The spleen holds a reservoir of platelets; it also removes old and damaged red blood cells.

Lymphoid Organs

The spleen, thymus gland, and tonsils Peyer's patches and bits of lymphatic tissue scattered in connective tissue All are composed of reticular connective tissue All help protect the body Only lymph nodes filter lymph

Collections of lymphoid tissue (MALT) that guard mucosal surfaces include

The thymus is the site of T cell maturation.

Plasma cells

These cells are able to produce antibodies

B- lymphocytes

These cells populate the germinal centers of lymphoid follicles

Which statement is true regarding lymph nodes?

They have fewer efferent than afferent (incoming) vessels.(This slows the flow of the lymph through the node.)

hybridoma

This type of cell can create an endless supply of antibodies & is made by fusing a plasma cell with a cancerous cell:

Name the two lymphatic collecting ducts and indicate the portion of the body that is drained by each.

Thoracic Duct (Left Lymphatic Duct) Drains Left and lower right (75%) of body Right Lymphatic Duct Drains upper right 25% of body

The lymphoid organ that functions primarily during youth and then begins to atrophy is what?

Thymus

This organ ensures that the T-lymphocytes are immunocompetent

Thymus

This organ's stroma is composed of hormone- secreting epithelial cells

Thymus

Which of the following is the major lymphoid organ that ""trains"" T-lymphocytes to become immunocompetent?

Thymus ( T cells develop in the thymus).

Lymphatic tissue and organs are organized into primary and secondary structures. What are the primary ones?

Thymus, Red bone marrow

Lymph nodes

the principal lymphoid organs, are clustered along lymphatic vessels. They filter lymph and help activate the immune system. are encapsulated val structures located along lymphatic vessels. They develop from lymph sacs that become invaded by mesenchymal cells. They are scattered throughout the body, usually in groups. Lymph enters them through afferent lymphatic vessels, is filtered to remove damaged cells and microorganisms, and exits through efferent lymphatic vessels. Foreign substances filtered by them are trapped by nodal reticular fibers. Macrophages then destroy some foreign substances by phagocytosis and lymphocytes bring about the destruction of others by immune responses. They are the site of proliferation of plasma cells and T cells. Many cancer cells are spread by way of the lymphatic system, producing clusters of

Chemical factors are localized on

the skin, in loose connective tissue, stomach and vagina

Whenever an allergic reaction occurs,

there is tissue injury

What else does Interferons (IFNs) do?

they enhance the activity of phagocytes and natural killer (NK) cells, inhibit growth, and suppress tumor formation: they may hold promise as clinical tools in AIDS and cancer treatment once they are more fully understood.

What name is given to the terminal duct draining most of the body?

thoracic duct

Thymus produced hormones

thymosin, thymulin, and thymopoietin that stimulates the maturation of T- lymphocytes.

The lymphoid organ that does not directly fight antigens is the

thymus

Blind-ended crypts are found in the

tonsils

This connective tissue divides lymph nodes into compartments

trabeculae