© 2009 the mcgraw-hill companies, inc. all rights reserved the lymphatic and immune systems...

© 2009 The McGraw-Hill Companies, Inc. All rights reserved

The Lymphatic and Immune The Lymphatic and Immune SystemsSystems

PowerPoint® presentation to accompany:

Medical AssistingThird Edition

Booth, Whicker, Wyman, Pugh, Thompson

32-2


Learning Outcomes32.1 List the pathways and organs of the lymphatic system

and give their locations.

31.2 Define lymph and tell how it is circulated in the body.

31.3 Define the terms infection, pathogen, and antigen.

31.4 List and describe the nonspecific body defense mechanisms.

31. 5 Explain the signs and causes of inflammation.

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Learning Outcomes (cont.)

32.6 Explain what is meant by body defenses.

32.7 Define B cells and T cells and describe their locations and functions.

32.8 Explain the importance of MHC proteins.

32.9 List the different types of T cells and describe their functions.

32.10 Explain how antibodies fight infection.

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32.11 List the different types of antibodies and tell how they differ.

32.12 Define complement proteins and give their function.

32.13 Explain the difference between the primary immune response and secondary immune response.

32.14 Explain the four different types of acquired immunities.

32.15 Describe the function of a vaccine.

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32.16 Define the terms cancer and carcinogen.

32.17 Describe how cancers are diagnosed and treated.

32. 18 Explain how cancers are classified.

32.19 Describe how allergies develop.

32.20 Describe the causes, signs and symptoms, and treatments of other common immune disorders.

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Introduction

Immune system Protects the body

against Bacteria Viruses Fungi Toxins Parasites Cancer

Lymphatic system Works with immune

system to remove disease-causing agents

Organs Thymus Spleen Lymph nodes

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The Lymphatic System

Network of connecting vessels Collects fluid (lymph) between cells and returns

it to bloodstream

Picks up lipids from digestive organs and transports them to blood stream

Functions to defend the body against pathogens

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Lymphatic System: Pathways

Lymphatic capillaries Extend into interstitial spaces Permeable, thin walls pick up fluid, now lymph Delivers lymph to lymphatic vessels

Lymphatic vessels Deliver lymph to lymph nodes

Cells in nodes can remove pathogens from lymph and start an immune response

Leaves nodes through efferent lymphatic vesselsLymph System

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Lymphatic System: Pathways (cont.)

Lymphatic trunks Receive lymph from efferent lymphatic vessels Deliver it to

Lymphatic collecting ducts Thoracic duct

Left side of head and neck, left arm, left side of thorax, entire abdominopelvic area, and both legs

Right lymphatic duct Right side of head and neck, right arm, and right side of chestLymph

System

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Lymphatic System: Tissue Fluid and Lymph

Interstitial fluid Fluid in spaces between cells that has leaked

from blood capillaries and has not been picked up by body cells

High in nutrients, oxygen, and small proteins Becomes lymph

Pushed through lymphatic vessels by squeezing action of neighboring skeletal muscles and breathing movement

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Back

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Lymphatic System: Nodes

Small, glandular structures

Located along paths of larger lymphatic vessels Afferent lymphatic vessels

– Lymph to node Efferent lymphatic vessels

– Lymph from node

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More lymph enters than can leave at one time

Cells in nodes Macrophages – digest unwanted

pathogens Lymphocytes – start an immune

response against pathogen

Nodes can generate some lymphocytes

Lymphatic System: Nodes (cont.)

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Lymphatic System: The Thymus and Spleen

Thymus Soft, bi-lobed organ

Located just above the heart in the mediastinum

Large in children, shrinks as we age

Functions Same as lymph nodes

Also produces lymphocytes

Produces thymosin – stimulates production of lymphocytes

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Spleen Largest lymphatic organ

Located in the upper left quadrant of abdominal cavity

Functions Filters blood similarly to lymph nodes

Removes worn-out red cells

If removed (splenectomy), liver takes over most of its

function

Lymphatic System: The Thymus and Spleen (cont.)

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Apply Your Knowledge

What are the lymphatic collecting ducts and what area do they drain?

ANSWER: The collecting ducts are: Thoracic duct, which drains the left side of the head and neck, left arm, left side of thorax, entire abdominopelvic area, and both legs; and the right lymphatic duct, which drains the right side of the head and neck, right arm, and right side of the chest.

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Defenses Against Disease Infection

The presence of a pathogen in or on the body

Pathogen A disease-causing agent

Innate immunity Nonspecific defenses to

protect against pathogens

Nonspecific defenses Species resistance

Mechanical barriers

Chemical barriers

Phagocytosis

Fever

Inflammation

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Defenses Against Disease: Specific Defenses

Immunities Protect against very

specific pathogens Antigens

Foreign substances in the body

Haptens Foreign substances too

small to start an immune response by themselves

Other substances Proteins – antibodies and

complements WBCs – lymphocytes and

macrophages Lymph system

Cytokines – assist in immune response regulation

Monokines – increase B cell production and stimulate WBC production

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Defenses Against Disease (cont.)

Two major types of lymphocytes

B Cells and T Cells

Recognize antigens in the body

T Cells Cell-mediated response Bind to antigens on cells

and attack them directly Secrete lymphokines that increase T cell production and directly kill cells with antigens

T Cells Cell-mediated response Bind to antigens on cells

and attack them directly Secrete lymphokines that increase T cell production and directly kill cells with antigens

B cells Respond to antigens by becoming plasma cells Plasma cells make antibodies Memory B cells produce stronger response with next exposure to antigen

B cells Respond to antigens by becoming plasma cells Plasma cells make antibodies Memory B cells produce stronger response with next exposure to antigen

Response

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T cell activation Begins when macrophage ingests and digests

pathogen with antigen on it Antigens are placed on cell membrane of

macrophage T cell recognizes and binds to antigen and the

major histocompatibility complex (MHC) on the surface of the macrophage

Now can divide to form other types of T cells

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Types Cytotoxic T cells

Protect body against viruses and cancer cells Helper T cells

Increase antibody formation, memory cell formation, B cell formation, and phagocytosis

Memory T cells Remember the pathogen that activated original T cell Later exposures trigger an immune response more

effective than initial response

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Natural killer (NK) cells

Type of lymphocyte

Primarily target cancer cells

Kill on contact

Do not recognize a specific antigen

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Identify whether each item refers to T cells, B cells, or NK cells:

___ Primarily target cancer cells

___ Respond to antigens by becoming plasma cells

___ Must be activated to respond to an antigen

___ Bind to antigens on cells and attack them directly

___ Kill on contact

___ Need macrophages and MHC for activation

___ Make antibodies against specific antigen

B

NK

T

T

T

B

NK

ANSWER:

Right on Target!

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Antibodies

Also called immunoglobulins IgA

Prevents pathogens from entering body IgD

Found on B cell membranes Thought to control B cell activity

IgE Found with IgA Involved in triggering allergic reactions

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Antibodies (cont.)

IgG Recognizes bacteria, viruses, and toxins Activates complements

IgM Large and binds to antigens on food, bacteria, or

incompatible blood cells Activates compliments

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Antibodies (cont.)

Actions that occur when antibodies bind to antigens Allow phagocytes to recognize and destroy antigens

Cause antigens to clump together, causing them to be destroyed by macrophages

Cover the toxic portions of antigens, making them harmless

Activate complement Group of proteins in serum that attack pathogens by forming holes

in them

Attract macrophages to pathogens and can stimulate inflammation

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What are the possible actions that occur when antibodies bind to antigens?

ANSWER: Possible actions include: They allow phagocytes to recognize and destroy antigens. They make antigens clump together, causing them to be destroyed by macrophages. They cover the toxic portions of antigens to make them harmless. They activate complements.

Very Good!

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Immune Responses and Acquired Immunity

Primary immune response occurs with first exposure to antigen Slow process Memory cells are formed

Secondary immune response with next exposure to same antigen Quick and carried out by memory cells Usually prevents person from developing disease from

the antigen

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Immune Responses and Acquired Immunity (cont.)

Naturally acquired active immunity Natural exposure to antigen – having an illness Makes antibodies and memory cells Long-lasting

Artificially acquired active immunity Injected with pathogen – immunizations Makes antibodies and memory cells Long-lasting

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Immune Responses and Acquired Immunity (cont.)

Naturally acquired passive immunity Acquired from mother

Breast milk Placenta

Short-lived

Artificially acquired passive immunity Injected with antibodies (such as antivenom) Short-lived

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ANSWER: Immunization is an artificially acquired immunity because a person develops this immunity by being injected with a pathogen and then making antibodies and memory cells against the pathogen.

After you give an immunization to a 2-year-old, her mother asks you why this will work to prevent her from getting a disease.

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Major Immune System Disorders Cancer

Uncontrolled growth of abnormal cells form malignant tumors

200 known types Treatment based on stage

0 – very early; cancer cells localizedI – spread to deeper layers or some in surrounding tissuesII – spread to surrounding tissues but contained in primary siteIII – spread beyond primary site into nearby areasIV – spread to other organsRecurrent – reappeared after treatment

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Major Immune System Disorders (cont.)

Allergies Immune response to an allergen

Can be excessive IgE antibodies bind to allergens and stimulate mast cells

to release histamine and heparin Triggers allergic response

Allergy shots Small amounts of allergen stimulates production of IgG to

prevent IgE from binding to antigen IgG antibodies do not stimulate mast cells, so immune response

is not generated

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Signs/symptoms Inhaled allergens – runny nose, sneezing, coughing, wheezing Ingested allergens – nausea, vomiting, diarrhea Skin allergens – rashes Allergens in blood – most life-threatening; can affect many

organs

Treatment Antihistamines, decongestants – OTC or prescription Epinephrine for anaphylaxis – vasoconstriction, increasing BP

Anaphylaxis – life-threatening response

Major Immune System Disorders (cont.)

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Common Immune System Disorders Autoimmune disease

Body attacks its own antigens Examples

Scleroderma Rheumatoid arthritis Multiple sclerosis Glomerulonephritis Chron’s disease Diabetes mellitus, type I

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Common Immune System Disorders (cont.)

Disorder Description AIDS Development of severe signs and symptoms

caused by HIV as it destroys lymphocytes; leaves immune system weakened and susceptible to other diseases

Chronic fatigue syndrome (CFS)

Condition of severe tiredness not relieved by rest and not related to other illnesses

Lymphedema Blockage of lymphatic vessels results in tissue swelling that increases over time

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Common IS Disorders (cont.)

Disorder Description Mononucleosis “Mono”; highly contagious viral infection

spread through saliva of infected person

Systemic lupus erythematous (SLE)

Autoimmune disorder; antibodies produces that target own cells and tissues; affects women more often than men

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Matching:

___ Immune response to a substance A. CFS

___ Blockage of lymphatic vessels B. SLE

___ “Kissing disease” C. Cancer

___ “Butterfly” rash on face D. Autoimmune disease

___ Severe tiredness E. Lymphedema

___ Uncontrolled growth of abnormal cells F. Mononucleosis

___ Body attack its own antigens G. Allergy

G

F

E

D

C

B

A

ANSWER:

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In Summary Immune system is the body’s major line of defense

Primary function – protect against infection, toxins, and cancer

Specific or nonspecific defenses Lymphocytes are major cells of immune system

Immune response may be primary or secondary Medical assistant must understand immune system

Aseptic technique Infection control Educate patients

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End of Chapter

Thought is an infection. In the case of certain

thoughts, it becomes an

epidemic.

~Wallace Stevens

© 2009 the mcgraw-hill companies, inc. all rights reserved the lymphatic and immune systems...

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