chapter 28 the lymphatic and immune systems 28-2 learning outcomes (cont.) 28.1 describe the...

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28The Lymphatic and Immune Systems

28-2


Learning Outcomes (cont.)

28.1 Describe the pathways and organs of the lymphatic system.

28.2 Compare the nonspecific and specific body defense mechanisms.

28.3 Explain how antibodies fight infection.

28-3


Learning Outcomes (cont.)

28.4 Describe the four different types of acquired immunities.

28.5 Describe the causes, signs and symptoms, and treatments of major immune disorders.

28-4


Introduction

• Immune system – Protects against

• Bacteria • Viruses • Fungi • Toxins • Parasites • Cancer

• Lymphatic system– Works with the

immune system

– Organs• Thymus• Spleen• Lymph nodes

28-5


The Lymphatic System

• Network of connecting vessels

• Functions to

– Collect lymph from between cells

– Collect lipids from digestive organs

– Defend the body against pathogens

28-6


Lymphatic Pathways

• Lymphatic capillaries– Collect fluid– Deliver lymph to lymphatic vessels

• Lymph vessels – lymph to nodes

• Lymph nodes – Remove pathogens

– Start immune response Lymph System

28-7


Lymphatic Pathways (cont.)

• Efferent lymphatic vessels lymphatic trunks

• Lymphatic collecting ducts– Thoracic duct– Right lymphatic duct

• Empty into blood streamLymph System

28-9


The Lymphatic System (cont.)

Area Drained by right lymphatic duct

Right lymphatic duct

Lymph nodes

Lymphatic trunks

Lymphatic vessels

Left internal jugular vein

Thoracic duct

Left subclavian vein

Thoracic duct

Cisterna chyli

28-10


Tissue Fluid and Lymph

• Interstitial fluid– Fluid in spaces between cells – High in nutrients, oxygen, and small proteins– Fluid not picked up by cells lymph

• Lymph moves by– Squeezing action of skeletal muscles– Squeezing action of breathing

28-11


Lymph Nodes

• Small, glandular structures

• Afferent lymphatic vessels ~ lymph to node

• Efferent lymphatic vessels ~ lymph from node

28-12


Lymph Nodes (cont.)

• Lymph pools in the nodes

• Cells in nodes– Macrophages ~ digest unwanted pathogens

– Lymphocytes ~ start an immune response against pathogen

• Nodes can generate some lymphocytes

28-14


The Thymus and Spleen

• Thymus

– Soft, bi-lobed organ located in the

mediastinum

– Functions

• Same as lymph nodes

• Also produces lymphocytes

• Produces thymosin – stimulates production of

lymphocytes

28-15


The Thymus and Spleen (cont.)

• Spleen

– Largest lymphatic organ

– Upper left quadrant of abdominal cavity

– Functions

• Filters blood similarly to lymph nodes

• Removes worn-out red cells

28-16


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.

28-17


Defenses Against Disease

• Infection – presence of a pathogen in or on the body

• Pathogen – disease-causing agent

• Innate immunity – nonspecific defenses

• Immunities – specific defenses

28-18


Non-Specific Defenses

• Species resistance

• Mechanical barriers– Skin– Mucous

membranes

• Chemical barriers

• Phagocytosis – phagocytes surround and destroy pathogens and unwanted debris

28-19


Non-Specific Defenses

• Fever

– Stimulates removal

of iron from blood

– Activates

phagocytic cells

• Inflammation

– Redness

– Heat

– Swelling

– Pain

28-20


Specific Defenses

• Immunities

• Antigens – Foreign substances in the body– On the surfaces of pathogens

• Haptens – foreign substances too small to start an immune response

28-21


Specific Defenses

• Antibodies – respond to specific antigens

• Complements – work with antibodies

• WBCs – lymphocytes and macrophages

28-22


Specific Defenses

• Cytokines – assist in immune response regulation

• Monokines– Increase B cell production

– Stimulate WBC production

28-23


Specific Defenses (cont.)

Two major types of lymphocytes

Both recognize antigens in the body

Diagram

T CELLSCell-mediated responseSecrete Lymphokines

B CELLSAntibody-mediated responsePlasma cellsMemory B cells

T Cells and B CellsT Cells and B Cells

28-25



• T cell activation– Macrophage ingests and digests a pathogen

with antigens on it

– Antigens are placed on the macrophage cell membrane next to a major histocompatibility complex (MHC)

– T cell binds to the antigen and MHC

Diagram

28-26



• Cytotoxic T cells

• Memory T cells

• Helper T cells– Increase antibody

formation

– Memory cell formation

– B cell formation

– Phagocytosis

28-27


Specific Disease (cont.)

• Natural killer (NK) cells

– Type of lymphocyte

– Primarily target cancer cells

– Kill on contact

– Do not recognize a specific antigen

28-28



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:

28-29


Antibodies

• Immunoglobulins

• IgA – prevents pathogens from entering body

• IgD – thought to control B cell activity

• IgE – involved in triggering allergic reactions

28-30


Antibodies (cont.)

• IgG– Recognizes bacteria, viruses, and toxins– Activates complements

• IgM – Binds to antigens on food, bacteria, or

incompatible blood cells– Activates compliments

28-31


Antibodies (cont.)

• Actions

– Allow phagocytes to recognize and destroy antigens

– Cause antigens to clump together

– Cover the toxic portions of antigens

– Activate complements

28-32



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.

28-33


Immune Responses and Acquired Immunities

• Primary immune response– Slow process– Memory cells are formed

• Secondary immune response– Quick and carried out by memory cells– Usually prevents person from developing

disease from the antigen

28-34


Immune Responses and Acquired Immunities (cont.)

• Naturally acquired active immunity– Natural exposure to antigen – Makes antibodies and memory cells

• Artificially acquired active immunity– Injected with pathogen – Makes antibodies and memory

cells

28-35


Immune Responses and Acquired Immunities (cont.)

• Naturally acquired passive immunity– Acquired from mother– Short-lived

• Artificially acquired passive immunity– Injected with antibodies – Short-lived

28-36



ANSWER: Immunization is an artificially acquired immunity . 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. What would you tell her?

28-37


Major Immune System Disorders

• Cancer

– Uncontrolled growth of abnormal cells

– Carcinogen

– Signs/symptoms vary

– Treatment based on staging

28-38


Major Immune System Disorders (cont.)

Stage Description

Stage 0Very early cancer. Cancer cells are localized in a few cell layers.

Stage I

Cancer cells have spread to deeper cell layers, or some may have spread to surrounding tissues.

Stage IICancer cells have spread to surrounding tissues but are considered contained in the primary cancer site.

28-39



Stage Description

Stage IIICancer cells have spread beyond the primary cancer site to nearby areas.

Stage IVCancer cells have spread to other organs of the body.

RecurrentCancer cells have reappeared after treatment.

28-40



• Allergies– Immune responses to an allergen

– IgE antibodies• Bind to allergens • Stimulate mast cells

– Allergy shots

– Anaphylaxis ~ life threatening allergic response

28-41



• Allergies (cont.)– Signs/symptoms are based on where

exposure occurs

– Treatment• Antihistamines, decongestants

• Epinephrine for anaphylaxis

28-42


Common Diseases and Disorders of the Immune System

• Autoimmune disease– Body attacks its own antigens

– Examples • Scleroderma• Rheumatoid arthritis• Multiple sclerosis• Glomerulonephritis• Crohn’s disease• Diabetes mellitus, type I

28-43


Common Diseases and Disorders of the Immune System (cont.)

Disorder Description

Acquired immunodeficiency syndrome

(AIDS)

Development of severe signs and symptoms caused by HIV as it destroys lymphocytes (T cells); 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

28-44


Common Immune System Disorders (cont.)

Disorder Description

Lymphedema Blockage of lymphatic vessels resulting in tissue swelling

Mononucleosis “Mono”; highly contagious viral infection spread through saliva of infected person

Systemic lupus erythematous (SLE)

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

28-45



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 E. Lymphedema

___ Severe tiredness F. Mononucleosis

___ Uncontrolled growth of G. Allergy

abnormal cells

___ Body attacks its own antigens

G

F

E

D

C

B

A

ANSWER:

28-46


In Summary

28.1 The lymph system is composed of pathways known as lymph vessels. In addition to the lymph vessels, the organs of the lymphatic system include lymph nodes, located throughout the body; the thymus, in the mediastinum; and the spleen, located in the LUQ.

28.2 Nonspecific body defenses include species resistance, mechanical and chemical barriers, phagocytosis, fever, and inflammation.

Specific defenses are immunities or defenses against very specific antigens created by B cells, T cells, and natural killer (NK) cells.

28-47


In Summary (cont.)

28.3 Antibodies work in the following ways: phagocytosis, antigen clumping, covering (inactivating) toxic portions of antigens, and activating complements. Antibodies are also known as immunoglobulins.

IgA prevents pathogens from entering the body;

IgD controls B cell activity;

IgE works with IgA in triggering allergic reactions;

IgG recognizes bacteria, viruses, and toxins and activates complements; and

IgM binds to antigens on food, bacteria, or incompatible blood cells. IgM also activates complements.

28-48


In Summary (cont.)

28.4 The four types of immune response are naturally acquired active immunity, such as when someone becomes ill and develops immunity; artificially

acquired active immunity, as when an injection is given against a pathogen, preventing illness; naturally acquired passive immunity, which occurs when an infant has its mother’s immunity for a short while after birth and through breast milk; and artificially acquired passive immunity, which occurs after injection of antibodies such as with an antivenom.

28-49


In Summary (cont.)

28.5 Diseases and disorders of the immune system include HIV infection, AIDS, cancer, and allergies, as well as other autoimmune diseases, in which the body attacks its own antigens.

The signs, symptoms and treatments are as numerous and varied as the diseases.

Some of the more common diseases and disorders are discussed in the Common Diseases and

Disorders of the Immune System section near the end of this chapter.

28-50


End of Chapter 28

Thought is an infection. In the case of certain

thoughts, it becomes an

epidemic.

~Wallace Stevens

chapter 28 the lymphatic and immune systems 28-2 learning outcomes (cont.) 28.1 describe the...

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