The Immune SystemThe Immune SystemLesson 1:Lesson 1:The Immune SystemsThe Immune Systems

Lesson ObjectivesUpon completion of this lesson, students should be able to …

Identify and discuss the anatomy of the immune system.

Discuss the functions of the immune system.

Explain the immune system and its response.

Composition of the Immune SystemTissuesOrgansPhysiological processes that identify

abnormal cellsForeign substancesForeign tissues, such as transplants

Structures Central to the Immune SystemCentral lymphoid tissue

bone marrow, thymusPeripheral lymphoid tissue

lymph nodes, spleen, and mucus membranes

Critical Thinking Questions1. What is so critical about the immune

system to one’s overall health?

2. If one has a compromised immune system would that shorten the person’s life?

The Immune Systemthroughout the bodypart of the lymphatic systemsubsystem of the CV system Primary fx is to defend against invasion Pathogens (viruses, bacteria, and fungi) Immunosuppressants, medications, and

stress can suppress system

The Lymphatic System

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Bone MarrowContains stem cells that create all the cellsProduces

RBC’sWBC’sPlateletsB cells Natural killer cells

Thymus Gland

Located posterior to the sternumManufactures infection-fighting T cells Helps distinguish normal T cells from those

that attack the bodyEnlarges during childhood Shrinks as we age

Peripheral Lymphatic System

Consists of the lymph nodes, spleen, and other lymphoid tissue

Lymph NodesDifferent sizes and

shapesMost are bean-

shaped, about 1 inch long

Covered with a thick fibrous capsule

Two Parts of Lymph NodesCortex

Populated mainly with lymphocytes

MedullaPrimarily made up of macrophages

B LymphocytesResponsible for circulating antibodies When an antigen enters the body,

B lymphocytes rapidly undergo mitosis and divide

This produces a large quantity of an antibody

Spleen Located in the ULQ of the abdomenLots of blood vesselsSpleen’s blood vessels are lined with

macrophagesswallow and digest debris in the blood

worn-out red blood cells and platelets

TonsilsLocated in the

depressionsof the throat and

the pharynxFx -filter bacteria aid in the

formation of white blood cells Factoid:

Tonsils used to be removed when infected.

Immune Troop Worksheethttp://vimeo.com/138062

The Immune SystemDefense against infectious organisms and

pathogenic invaders Immune response

cells, tissues, and organs work together to attack pathogen

white blood cells (WBCs), seek out and destroy harmful organisms

PhagocytesPhagocytes

WBC that attacks the invading organism most common are neutrophils, which fight off

bacteria

LymphocytesLymphocytes

WBC allows the body to remember previous invading organisms

Originate in the bone marrow If stays there, it matures into B cells If moves to the thymus gland, they mature

into T cells

B and T LymphocytesB lymphocytes

Seek out invading organisms and send defenses to attach onto them

T cellsDestroy the organisms that the B lymphocytes have id

AntigenForeign substance that invades the body When an antigen is detected, several types of

cells work together to recognize and respond to it

These cells trigger the B lymphocytes to produce antibodies

This process is known as humoral immunity

Antibodies

Specialized proteins that lock onto specific antigens

ImmunoglobulinsAntibodies are found in blood, tissue fluids, and

many secretions

B Cells of the Immune System

Once antibodies have been produced, they remain in the body

If re-infected, the antibodies are already there to neutralize it

antibodies can recognize an antigen and lock onto it, but are not capable of destroying it.

That is the job of the T cells.

T Cellsdestroys antigens which have been tagged

by antibodies

Immunity The body’s ability to defend itself

against pathogens 3 Forms

Innate ImmunityBorn with innate, or natural,

immunity Renders many of the viruses and

bacteria incapable of harming infantProvided by :

Skin Mucous membranesMother

Active Immunityby infection or with a vaccineIs permanent ??

Types of Active ImmunityAcquired active immunity

exposed to a live pathogendevelops the diseaseand becomes immune (primary immune

response)

Artificially acquired active immunityinduced by a vaccine (antigen)stimulates a primary response against the

antigen without causing symptoms of the disease

Passive Immunity“Borrowed” from another source and lasts for

only a short time An inherited immunity to certain diseases

Medical SpecialistsAllergistImmunologistOncologist