Functions of the Immune System

Functions of the Immune System

To protect the entire body from a variety of harmful substances pathogenic microorganisms allergens toxins malignant cells

Antigen-Antibody Reactions

Antigen-Antibody Reactions

Antigen - any substance that the body regards as foreign (virus, bacterium, toxin)

Antibody - a disease fighting protein developed by the body in response to the presence of an antigen

Structures of the Immune SystemStructures of the Immune System

Not contained in a single system

Action depends on structures from lymphatic, cardiovascular, and Integumentary systems

Works primarily through antigen-antibody reaction

Check for Understandin

g1.1. What other body What other body

systems work with the systems work with the immune system? immune system? How How do they do they work together? work together? Hint* Think back to the Hint* Think back to the past units. past units.

2.2. What are all the What are all the different vocabulary different vocabulary words that mean words that mean viruses, bacteria and viruses, bacteria and fungus?fungus?

External Defenses

Intact skin and mucous membranes Form physical barriers that stop the

entry of pathogens

Certain cells of the mucous membranes produce mucus A viscous fluid that traps microbes

and other particles

Body’s Defenses In the trachea, ciliated epithelial cells

Sweep mucus and any entrapped microbes upward, preventing the microbes from entering the lungs

Figure Figure 43.343.3

1010mm

•Secretions of the skin Secretions of the skin and mucous membranesand mucous membranes

•Provide an Provide an environment that is environment that is often hostile to often hostile to microbesmicrobes

•Secretions from the skinSecretions from the skin•Give the skin a pH Give the skin a pH between 3 and 5, between 3 and 5, which is acidic enough which is acidic enough to prevent colonization to prevent colonization of many microbesof many microbes•Also include Also include lysosymeslysosymes, that , that digests the cell walls of digests the cell walls of many bacteriamany bacteria

Check for Understandin

g1.1. What is the trachea? Where What is the trachea? Where

is it located?is it located?2.2. What is an epithelial cell?What is an epithelial cell?3.3. What is a lysosome? What is a lysosome?

Where is it found? Why Where is it found? Why would skin cells need them would skin cells need them more? more? Hint* Think back to the Hint* Think back to the cell unit.cell unit.

4.4. If your body is fighting a war If your body is fighting a war against pathogens, why is it against pathogens, why is it smart to put defenses where smart to put defenses where it did? Where are they it did? Where are they placed? Why is that placed? Why is that strategic?strategic?

ImmunityImmunityImmunity-state of being resistant or not susceptible

to a specific disease

Body’s reaction to invaders

Passive Acquired

Active Acquired

Acquired Immunity Passive

Acquired

Injecting antibodies (not patients) to fight a disease

Mother to newborn

Active Acquired

Natural types are people recovering from a disease and can’t get it again

Artificial types are vaccines

Check for Understandin

g1.1. What is the difference What is the difference

between injecting between injecting antibodies and antibodies and injecting a vaccine? injecting a vaccine? How does your body How does your body respond differently?respond differently?

WBCs for Immune Reactions

WBCs for Immune Reactions

Monocytes - formed in bone marrow/transported where needed by body become macrophages

Macrophage - phagocytic cell that protects body by ingesting invading cells

Lymphocytes - major class of WBCs formed in lymphatic

tissue

Figure Figure 43.143.1

33mm

Where

Imm

une

Cells co

me fro

m

Macrophage•Large numbers are Large numbers are released during infectionsreleased during infections

•Short lived – die after Short lived – die after digesting bacteriadigesting bacteria

•Found in the organs, not the blood.•Made in bone marrow as monocytes, called macrophages once they reach organs.•Initiate immune responses as they display antigens from the pathogens to the lymphocytes.

Phagocytosis

Process of engulfing and destroying cells.

Lymphocytes T cells or T Lymphocytes

mature in thymus gland Cell mediated immunity

B cells or B Lymphocytes mature in bone marrow antibody-mediated

immunity

Check for Understandin

g1.1. What is the What is the

relationship between relationship between monocytes and monocytes and macrophages? macrophages?

2.2. What is the What is the relationship between relationship between Lymphocytes, B-Cells Lymphocytes, B-Cells and T-Cells?and T-Cells?

3.3. Where are Where are macrophages found?macrophages found?

4.4. Where are B-Cells Where are B-Cells found?found?

5.5. Where are T-Cells Where are T-Cells found?found?

T Cell or T LymphocyteT Cell or T Lymphocyte

T Cell (cell mediated immunity) Helper T-cells

The Helper T-cells coordinate the attack.

Killer T-cells Killer  T-cells do the

work of destroying the infected cells.

B-Cells• There are 10 million different B-

lymphocytes, each of which make a different antibody.

• Some activated B cells become PLASMA CELL PLASMA CELL .

• Plasma cells produce antibodies ~1000/sec

Antibodies

Antibodies don’t Antibodies don’t attack viruses. attack viruses.

Antibodies attach Antibodies attach to viruses, and to viruses, and bring them in bring them in clumps to clumps to macrophage. macrophage.

B-Cells Other Roles Some activated B cells MEMORY CELLS.

Memory cells divide rapidly as soon as the antigen is reintroduced.

When the pathogen/infection infects again it is destroyed before any symptoms show.

Check for Understandin

g1.1. What is the relationship What is the relationship

between antibodies and between antibodies and macrophages?macrophages?

2.2. Where do antibodies Where do antibodies come from?come from?

3.3. How many T-Cells are How many T-Cells are there and what are their there and what are their individual jobs?individual jobs?

4.4. Why are B-Cells so Why are B-Cells so special that they are special that they are called “morphing” cells?called “morphing” cells?

Major events in the local inflammatory response

Figure 43.6Figure 43.6

PathogenPathogen PinPin

MacrophageMacrophage

Chemical signalsChemical signals

CapillaryCapillaryPhagocytic cellsPhagocytic cells

Red blood cellRed blood cell

BloodBloodclottingclottingelementselements

Blood clotBlood clot

PhagocytosisPhagocytosis

Fluid, antimicrobial proteins, Fluid, antimicrobial proteins, and clotting elements move and clotting elements move from the blood to the site.from the blood to the site.Clotting begins.Clotting begins.

22Chemical signals released Chemical signals released by activated macrophages by activated macrophages and mast cells at the injury and mast cells at the injury site cause nearby capillaries site cause nearby capillaries to widen and become more to widen and become more permeable.permeable.

11 Chemokines released by various Chemokines released by various kinds of cells attract more kinds of cells attract more phagocytic cells from the bloodphagocytic cells from the bloodto the injury site.to the injury site.

33 Neutrophils and macrophagesNeutrophils and macrophagesphagocytose pathogens and phagocytose pathogens and cell debris at the site, and thecell debris at the site, and the tissue heals.tissue heals.

44

Function of Lymphatic

System• Returns excess interstitial fluid (from

tissues) to circulatory system

• Absorption of fat and fat soluble vitamins from GI system

• Defense against invading pathogens and disease

Lymphatic System

Lymphatic System

Major structures lymph vessels lymph nodes lymph fluid Tonsils Lymphatic trunks Collecting ducts

Also spleen thymus

Lymph SystemLymph System Fluid in lymphatic

capillaries are called “lymph”

Lymphatic vessels are like blood veins with valves

Lymph nodes are specialized organs

Lymph NodesLymph Nodes located in lymph

vessels

small round or oval structures (filters)

depositories for cellular debris

bacteria and debris phagocytized

Swollen if bacteria is overwhelming

Check for Understandin

g1.1. Glue the lymph model Glue the lymph model

in your notebook and in your notebook and label all major lymph label all major lymph nodes and clusters. nodes and clusters.

2.2. Why are lymph nodes Why are lymph nodes so important?so important?

3.3. Why are Why are lymph lymph vessels and the vessels and the cardiovascular system cardiovascular system so closely connected?so closely connected?

SpleenSpleen Sac-like mass of lymphatic tissue

filter for blood from lymph

Phagocytic cells (macrophages) used to destroy bacteria and toxins

ThymusThymus Primary role: matures T

cells

T cell development: cells migrate from bone marrow and differentiate into T cells

Thymus gets progressively smaller (and less active) through life

TonsilsTonsils Used to catch

pathogens before they are swallowed into the GI tract.

any or all may become so loaded with bacteria that the pathogens gain dominance.

Should not be Should not be removed unless removed unless absolutely absolutely necessarynecessary

Lymph Carry proteins back into blood

Absorb dietary fats

Transport pathogens to lymph nodes to be destroyed

Maintain balance of pressure in tissue fluid

Exercise is important

Lymphatic vessels are not muscles

Need physical exercise to contract and push lymph through vessels

Squeezing vessels cause flow to go into collecting ducts

Check for Understandin

g1.1. Why do elderly people get sick Why do elderly people get sick

more often than young adults? more often than young adults? Give specific examples and Give specific examples and reference specific organs. reference specific organs.

2.2. What immune cells are found in What immune cells are found in the bone marrow? the bone marrow? Hint* Look Hint* Look through all your notes.through all your notes.

3.3. What immune cells are found in What immune cells are found in the Thymus? the Thymus?

4.4. How areHow are blood vessels and blood vessels and lymph vessels different? lymph vessels different?

5.5. Why do people say that Why do people say that exercise and health go exercise and health go together?together?

Acquired Immune Deficiency Syndrome

(AIDS)

Acquired Immune Deficiency Syndrome

(AIDS) Caused by HIV (Human Immunodeficiency Virus)

HIV infects T-helper cells with often a long incubation of up to 10 years

AIDS name applied during advanced stages of disease

After immune system destroyed, opportunistic infections occur.

Autoimmune DisordersAutoimmune Disorders

Antigens stimulate development of antibodies that are unable to distinguish antigens of internal cells.

Body makes antibodies and T cells against itself and attacks own tissues.

Multisystemic involvement.

Myasthenia gravis, rheumatoid arthritis

Edema Hypoproteinemia

lowers osmotic pressure within blood large amounts of plasma pass out of blood

poor lymph drainage

increased capillary permeability

congestive heart failure

localized edema, ascites

Hemophilia Hereditary blood clotting disorder

sex-linked, usually in men

lack factor VIII, essential for blood clotting

hematomas

hemarthrosis

Infectious Mononucleosis

Infectious Mononucleosis

Acute infection caused by virus.

Fever, sore throat, swollen lymph glands, atypical lymphocytes, splenomegaly, hepatomegaly, abnormal liver function, and bruising.

transmitted by droplet infection

Infection confers permanent immunity

Treatment symptomatic

Oncology, the study of tumors

Oncology, the study of tumors

Metastasis, Metastasize

Carcinoma Malignant Melanoma Adenocarcinoma

Sarcoma (arises from bone, fat, muscle, etc.) Osteocarcoma Osteosarcoma Myosarcoma Myeloma

Leukemia Major oncological disorder

of blood-forming organs

Monocytes develop quickly in to B or T cells but do not die

Cancerous B or T cells overcrowd the body and organs until other cells can’t function normally

Hodgkin’s DiseaseHodgkin’s Disease Malignant disorder- Cancer

cells can spread

Cancerous B cells begin to form and grow abnormally large

Painless, progressive enlargement of lymph tissue

Anorexia, weight loss, anemia

Kaposi’s Sarcoma Malignancy associated with AIDS

lesions emerge as purplish-brown macules and develop into plaques and nodules