What is the lymphatic system consisted of?

*A fluid called lymph flowing within lymphatic vessels(lymphatics)
*Several structures and organs that contain lymphatic tissue(specialized reticular tissue containing large numbers of lymphocytes)
*Bone marrow, which is the site of lymphocyte production

What are the lymphatic system functions?

*To drain interstitial fluid
*return leaked plasma proteins to the blood
*transport dietary fats
*protect against invasion by nonspecific and specific immune responses.

What do lymphatic vessels begin as?

Blind-ended lymph capillaries in tissue spaces between cells.

How is lymph formed?

Interstitial fluid drains into lymphatic capillaries, thus forming lymph.

Lymph capillaries merge to form larger vessels, called (a)_____ _____, which convey lymph into and out of structures called (b)_____ _____.

(a) Lymphatic vessels
(b) Lymph nodes

What is the passage of lymph?

*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)

Lymph flows as a result of ...

the milking action of skeletal muscle contractions and respiratory movements. It is also aided by lymphatic vessel valves which prevent backflow of lymph.

The _____ _____ 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.

thoracic duct

The _____ _____ ______ drains lymph from the upper right side of the body.

right lymphatic duct

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

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

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

Lymph nodes

What is the process once lymph enters the nodes?

*lymph enters nodes through afferent lymphatic vessels
*is filtered to remove damaged cells and microorganisms
*exits through efferent lymphatic vessels

Foreign substances filtered by the lymph nodes are trapped by (a)_____ _____ ______.

(b)_____ then destroy some foreign substances by phagocytosis and (c)_____ bring about the destruction of others by immune responses.

(a) nodal reticular fibers

(b) macrophages

(c) lymphocytes

_____ _____ are the site of proliferation of plasma cells and T cells.

lymph nodes

Why is the knowledge of the location of the lymph nodes and the direction of lymph flow important in the diagnosis and prognosis of the spread of cancer by metastasis?

Many cancer cells are spread by way of the lymphatic system, producing cluster of tumor cells where they lodge.

_____ are multiple aggregations of large lymphatic nodules embedded in a mucous membrane at the junction of the oral cavity and the pharynx.

tonsils

The tonsils include the (a)_____, (b)_____, and (c)_____ _____.

(a) pharyngeal(adenoid)

(b) palatine

(c) lingual tonsils

The tonsils are situated strategically to ...

protect against invasion of foreign substances and participate in immune responses by producing lymphocytes and antibodies.

The _____ is 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 diaphram.

spleen

The spleen is a site of ...

* B cell proliferation into plasma cells
* phagocytosis of bacteria and worn-out or damaged red blood cells and platets
* storage of blood

Abdominal trauma frequently causes a _____ _____ which, due to its capacity for blood storage, may cause severe intraperitoneal hemorrhage and shock.

ruptured spleen

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

Splenectomy

The _____ ______ lies between the sternum and the heart and functions in immunity as the site of T cell maturation.

thymus gland

Lymphatic vessels develop from (a)_____ _____, which develop from (b)_____. Thus, they are derived from (c)_____.

(a) lymph sacs

(b) veins

(c) mesoderm

Lymph nodes develop from (a)_____ _____ that become invaded by (b)_____ _____.

(a) lymph sacs

(b) mesenchymal cells

The ability to ward off disease using a number of defenses is called _____.

resistance

Lack of resistance is called _____.

susceptibility

Disease-producing organisms

pathogens

_____ _____ refers to a wide variety of body responses against a wide range of pathogens and their toxins.

Nonspecific resistance

What are the three lines of defense?

1st line: mechanical and chemical factors/barriers

2nd line: antimicrobial substances
*transferrins
*interferon
*complement
*properdin

3rd line: (3 parts)
*phagocytosis
*inflammation
*fever

_____ _____ include the intact epidermis layer of the skin, mucous membranes, the lacrimal apparatus, saliva, mucus, cilia, the eppiglottis,and the flow of urine.

Mechanical defenses

_____ and _____ also may be considered mechanical processes that expel microbes.

Defecation and vomiting

_____ _____ are localized on the skin, in loose connective tissue, stomach and vagina.

Chemical factors

The skin produces _____, which has a low pH due to the presence of unsaturated fatty acids and lactic acid.

sebum

_____ is an enzyme component of sweat which also has antimicrobial properties.

Lysozyme

Areolar(loose) connective tissue contains _____ _____ , which helps contain infections to a localized area.

hyaluronic acid

(1)_____ _____ renders the stomach nearly sterile since its low pH(1.0 - 2.5)kills many bacteria and destroys most of their toxins;(2)_____ _____ also are slightly acidic.

(1) gastric juice
(2) vaginal secretions

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

Antimicrobial substances

What are the four types of antimicrobial substances?

*transferrins
*interferon
*complement
*properdin

Body cells infected with viruses produce proteins called _____. Once produced and released from virus-infected cells _____ diffuses to uninfected neighboring cells and binds to surface receptors,inducing uninfected cells to synthesize antiviral proteins that interfere with or inhibit viral replication. _____ also enhance the activity of phagocytes and natural killer(NK) cells,inhibit cell growth, and suppress tumor formation.

Interferons(IFNs)

_____ ______ ______ have the ability to kill a wide variety of infectious microbes plus certain spontaneously arising tumor cells, their mechanisms of action and target recognition are poorly understood.

Natural killer (NK) cells

Natural killer cells are a type of _____.

T cells

A group of about 20 proteins present in blood plasma and on cell membranes comprises the _____ _____; when activated, these proteins enhance certain immune, allergic, and inflammatory reactions.

complement system

What are the three parts of the third line of defense?

*phagocytosis
*inflammation
*fever

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

Phagocytosis

What are the two categories of phagocytes?

*granulocytes(microphages--neutrophils and eosinophils)

*macrophages (fixed and wandering)

What are the four phases of the mechanism of phagocytosis?

*chemotaxis
*adherence
*ingestion
*killing

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

Inflammation

Inflammation is usually characterized by what symptoms?

*redness
*pain
*heat
*swelling
*loss of function may be a fifth symptom, depending on the sight and extent of the injury

The inflammatory response serves as a protective and defensive role by ...

*eliminating microbes, toxins, or foreign material from the site of injury
*preventing their spread to other organs
*preparing the site for tissue repair

It is an attempt to restore homeostasis.

What are the stages of the inflammatory response?

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

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

*histamine
*kinins
*prostaglandins(PGs)
*leukotrienes(LTs)
*complement

After phagocytes engulf damaged tissue and microbes, they eventually die, forming a pocket of dead phagocytes and damaged tissue and fluid called (1)_____. This must drain out of the body or it accumulates in a confined space, causing an (2)_____. An (3)_____ may result from a prolonged inflammatory response to continuously injured tissue.

(1) pus
(2) abscess
(3) ulcer

_____ 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.

Fever

Specific resistance to disease involves the production of a specific lymphocyte or (1)_____ against a specific (2)_____ and is called (3)_____.

(1) antibody(Ab)
(2) antigen(Ag)
(3) immunity

The branch of science that deals with the responses of the body when challenged by antigens is called _____.

immunology

Both T and B cells derive from stem cells in _____ _____.

Bone marrow

T cells complete their maturation and develop immunocompetence(the ability to carry out immune responses if properly stimulated) in the ______

Thymus

Before T cells leave the thymus or B cells leave the bone marrow, they acquire several distinctive surface proteins; some function as _____ _____, molecules capable of recognizing specific antigens.

antigen receptors

_____ _____ _____ refers to destruction of antigens by T cells. It is particularly effective against intracellular pathogens, such as fungi, parasites, and viruses; some cancer cells; and foreign tissue transplants; thus, _____ always involves cells attacking cells.

Cell-mediated immunity (CMI)

_____ ______ ______ refers to destruction of antigens by antibodies. It works mainly against antigens dissolved in body fluids and extracellular pathogens,primarily bacteria, that multiply in body fluids but rarely enter body cells.

Antibody-mediated (humoral) immunity (AMI)

Often a pathogen provokes what type of immune response?

Both CMI and AMI

_____ are chemical substances that are recognized as foreign when introduced into the body. They are both immunogenic and reactive. They are large, complex molecules--most often proteins, but sometimes nucleoproteins,lipoproteins,glycoproteins, and certain large polysaccharides.

Antigens (Ags)

Specific portions of antigen molecules, called (1)_____ _____, or (2)_____ trigger immune response.

(1)antigenic determinants
(2)epitopes

Antigen receptors exhibit great diversity due to _____ ______.

genetic recombination

_____ ______ _____ _____ are unique to each person's body cells. These self-antigens aid in the detection of foreign invaders.

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

All cells except _____ desplay MHC class I antigens.

RBs

_____ can recognize and bind to antigens in extracellular fluid.

B cells

_____ can only recognize fragments of antigenic proteins that first have been processed and presented in association with MHC self-antigens.

T cells

_____ fragments from foreign antigens help stimulate MHC molecules.

Peptide

Most cells of the body can process and present _____ ______, antigens that were synthesized in a body cell(e.g. viral proteins from virus-infected cells).

endogenous antigens

Cells called _____ _____ _____ process exogenous antigens(antigens formed outside the body)and present them together with MHC class II molecules to T cells. _____ include macrophages, B cells, and dendritic cells.

Antigen-presenting cells(APCs)

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

*phagocytosis or endocytosis of the antigen
*partial digestion
*fusion of vesicles
*binding of peptide fragmentsto MHC-II molecules
*exocytosis

_____ are small protein hormones needed for many normal cell functions. Some of them regulate immune responses.

Cytokines

An _____ is a protein that can combine specifically with the antigenic determinant on the antigen that triggered its production.

antibody (Ab)

Antibodies consist of _____ and _____ chains and _____ and _____ portions.

heavy (H) and light (L) chains
variable and constant portions

Based on chemistry and structure, antibodies are grouped into five principal classes, each with specific biological roles. What are the five classes?

IgG
IgA
IgM
IgD
IgE

In a(1) _____ ______ ______ ______, an antigen is recognized(bound), a small number of T cells proliferate and differentiate into a clone of (2)_____ ______(a population of identical cells that can recognize the same antigen and carry out some aspect of the immune attack), and the antigen(intruder) is eliminated.

(1)cell-mediated immune response
(2)effector cells

_____ ______ recognize antigens fragments associated with MHC molecules on the surface of a body cell.

T cell receptors (TCRs)

Proliferation of T cells requires _____, by cytokines such as interleukin(IL-1) and interleukin-2(IL-2), or by pairs of plasma membrane molecules, one on the surface of the T cell and a second on the surface of an APC.

co-stimulation

Name five subpopulations of T cells.

*Helper T cells(or T4 cells)
*Cytotoxic T cells(or T8 cells)
*Delayed-type hypersensitivity T cells
*Suppressor T cells
*Memory T cells

_____ display CD4 protein, recognize antigen fragments associated with MHC-II molecules, and secrete several cytokines, most importantly, interleukin-2

Helper T cells, or T4 cells

_____ develop from T cells that display CD8 protein and recognize antigen fragments associated with MHC-1 molecules.

Cytotoxic T cells or T8 cells

_____ produce cytokines and are important in hypersensitivity(allergic)responses.

Delayed-type hypersensitivity T cells

_____ are thought to be a class of T cells distinct from Th and Tc cells.They appear to down regulate immune responses by producing cytokines such as TGF-B which inhibits proliferation of B cells and T cells.

Suppressor 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.

Memory T cells

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 invader cells by secreting (1)_____, which causes cytolysis; or (2)_____, which causes fragmentation of the DNA of a target cell. The also indirectly secrete (3)_____ _____ which attracts neutrophis and macrophages to the site and greatly increases their phagocytic activity. Finally, they detach from the target cell and can seek out and destroy another invader that displays the same antigen.

(1)perforin (directly)
(2)lymphotoxin (directly)
(3)gamma interferon (indirectly)

Whereas (1)_____ leave lymphoid tissue to meet a foreign antigen, (2)_____ stay put.

(1) cytotoxic t cells
(2) b cells

An activated B cell develops into a clone of antibody-producing plasma cells. These cells produce antibody at an incredible rate of (1)_____ molecules per second per cell for (2)_____ days until the plasma cell dies.

(1) 2000
(2) 4-5

The activated B cells that do not differentiate into plasma cells remain as _____, ready to respond more rapidly and forcefully should the same antigen appear at a future time.

memory b cells

(1)_____ _____ 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 (2)_____. They are important in measuring levels of a drug in a patient's blood and in diagnosis of pregnancy, allergies, and diseases such as hepatitis, rabies, and some sexually transmitted diseases.

(1)monoclonal antibodies (MAbs)
(2)hybridoma

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

Immunological memory