Lesson Overview Lesson Overview Infectious Disease List of Contageous diseases.

Lesson OverviewLesson Overview Infectious DiseaseInfectious Disease

List of Contageous diseases


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Past due -Ch 21:1-3 Target sheet (1 source)-Prokaryotes, Fungi-10 articles?-Bacterial Lab report?-Test makeup?

New Unit- Quiz next Tues.Ch 35:2-3 Immune System one source OK


Targets: Chapter 35:2-3 The Immune SystemCh 35.2 Body Defenses Against Infection

1.Explain what a non-specific immune defense is:-Describe the “First Line of Defense”. Give examples. The skin, release of tears, secretions, mucus prevent entry of germs, may inhibit germ growth - Describe the “Second Line of Defense”. Give examples. After invasion, the inflamatory response causes soreness, mast cells release histamines causing swelling.Fever, speeds up immune system, and may slow down pathogen growth.Interferons, can interere with viral reproduction. 2


Inflammatory Response The inflammatory response causes infected areas to become red and painful, or inflamed.

The response begins when pathogens stimulate cells called mast cells to release chemicals known as histamines.

Histamines increase the flow of blood and fluids to the affected area.


Inflammatory Response Fluid leaking from expanded blood vessels causes the area to swell.

White blood cells move from blood vessels into infected tissues.


Inflammatory Response Many of these white blood cells are phagocytes, which engulf and destroy bacteria.

All this activity around a wound may cause a local rise in temperature. That’s why a wounded area sometimes feels warm.

Lesson OverviewLesson Overview Infectious DiseaseInfectious Disease2 . Explain what a specific immune defense is. Identifies what is foreign vs. self. It’s job is to destroy invaders.-Explain what it means to “Recognize Self” vs. “Recognize Nonself”. It should ID but not harm what belongs to “self”, but should tag and destroy invading pathogens. It will destroy and remember specific pathogens. -Define Antigens: (Are they invaders or part of the response?) These are foreign molecules located on the surface of bacteria and viruses that stimulate the immune response. They trigger specific immune defenses.Antibodies are created to attach to these antigens so that other immune system “weapons” can destroy them. (tagged for destruction)

Lesson OverviewLesson Overview Infectious DiseaseInfectious DiseaseThe body has 2 styles of specific defenses against pathogens. (see diagram in text 35.2)(a). Humoral Immunity has the job of “tagging” invaders to be destroyed later. This happens in the body fluids.(b)Cell-mediated immunity has the job of identifying and destroying infected cells that were ” tagged” ealier.3. Humoral immunity: Define or explain the following: (diagrams may help) -Antibody’s job and strutureSpecific Antibodies are created to attach to invading antigens so that other immune system “weapons” can destroy them. (tagged for destruction)-Plasma cellsWork in the blood stream to releaseantibodies find and “tag” pathogens for destruction.


Antigens The main role of antibodies is to tag antigens for destruction by immune cells.

Antibodies may be attached to particular immune cells or may be free-floating in plasma.

The body makes up to 10 billion different antibodies.

The shape of each type of antibody allows it to attach to one specific antigen.


Lymphocytes The main working cells of the immune response are B lymphocytes (B cells) and T lymphocytes (T cells).

B cells are produced in, and mature in, red bone marrow.

B cells have embedded antibodies and discover antigens in body fluids.


Lymphocytes T cells are produced in the bone marrow but mature in the thymus—an endocrine gland.

T cells must be presented with an antigen by infected body cells or immune cells that have encountered antigens.


-Memory B cells (form in bone, work in fluids)-After the “war is won”, Memory B cells are kept alive just in case another invasion occurs in the future. If it -does, they are ready to “tag” the enemy quickly.- This is how vaccines work. 4. Cell Mediated Immunity (2nd style of specific defense) has the job of identifying and destroying infected cells that were ” tagged” earlier. Define or explain the following: (diagrams may help)-Lymphocytes (B and T)General term for the major players in the immune defense system-Helper T cells (form in bone but mature in the thymus)Quickly activate other types immune cells-Memory T cells (form in bone but mature in the thymus) Memory T cells are ready for quick future warfare-Cytotoxic T cells kill tagged pathogens (big guns)


Macrophages “eat” invading viruses and display the foreign antigens so the various B & T cell soldiers can get prepared to fight other invaders.

White blood cells, phagocytes, engulf bacteria.


Ch. 35.3 Fighting Infectious Disease5. Explain how a vaccine works. Vaccines introduce a killed or de-activated pathogen (antigen) so the immune system can develop antibodies designed to prevent a future infection of the same live or active virus or bacteria. The “antigen” is the part of the germ that the immune system can recognize as an invader in the future. It can quickly attack it when this germ invades in the future.Vaccines can’t “treat” or cure once the person is sick.

-Explain the differences between “Active immunity” and “Passive immunity”. Give examples. “Active immunity” is what happens when the immune system creates memory B and memory T cells after being exposed to “antigens” given in a vaccine. Person’ defenses are ready for future attacks. “Passive immunity” is when antibodies created in another organism are injected to give temporary help in fighting an attack. (borrowed weapon in an emergency)


6. What steps can be taken to improve public health and prevent infectious diseases? Clean water and food supply, public sanitation methods, vaccinations, education about how to prevent spreading germs, enforce laws that protect us.7. Explain what “New” and “Re-Emerging Diseases” are. Give examples. Newer diseases include AIDS, SARS (viral respiratory infection), West Nile virus spread by mosquitoes, Ebola, avian influenze (“bird” flu), monkey pox, hantavirus.Re-emerging: TB bacteria, MRSA bacteria and Malaria (protist parasite) evolved resistance to antibiotic drugs

Measles and whopping cough have reappeared due to people not getting vaccinated.

What are Vectors? Vectors are organisms that help transfer diseases to other species.EX. Malaria, lime’s disease, West Nile virus are spread by mosquitoes or ticks.Hantavirus is spread by rodents.

What is a Zoonosis? Zoonosis is a disease that is passed from an animal to a human.Illegal trade of exotic wild animals has led to some of this. In some parts of the world these animals are hunted and eaten increasing the odds that a disease will spread to humans.8. Explain how misuse of antibiotics is related to the re-emergence of some diseases.Over use of antibiotic drugs has led to the evolution of drug- resistance in bacteria like TB and MRSA.


Humoral Immunity The immune response that defends against antigens in body fluids, such as blood and lymph, is called humoral immunity.

B cells play the major role in humoral immunity.

When a pathogen invades the body, its antigens are recognized by antibodies on the surfaces of a few existing B cells.

Antibodies are the main weapons of the humoral immune response.


Humoral Immunity An antibody is shaped like the letter Y and has two identical antigen-binding sites.

The shapes of the binding sites enable an antibody to recognize a specific antigen with a complementary shape.


Humoral Immunity When an antigen binds to an antibody carried by a B cell, T cells stimulate the B cell to grow and divide rapidly.

That growth and division produces many B cells of two types: plasma cells and memory B cells.


Plasma Cells Plasma cells produce and release antibodies that are carried through the bloodstream.

These antibodies recognize and bind to free-floating antigens or to antigens on the surfaces of pathogens.

When antibodies bind to antigens, they signal other parts of the immune system to attack and destroy the invaders.

Some types of antibodies can disable invaders until they are destroyed.


Cell-Mediated Immunity When a cell is infected by a pathogen or when a phagocyte consumes a pathogen, the cell displays a portion of the antigen on the outer surface of its membrane.

This membrane attachment is a signal to circulating T cells called helper T cells.


Cell-Mediated Immunity Activated helper T cells divide into more helper T cells, which go on to activate B cells, activate cytotoxic T cells, and produce memory T cells.


Cell-Mediated Immunity Cytotoxic T cells hunt down body cells infected with a particular antigen and kill the cells.

They kill infected cells by puncturing their membranes or initiating apoptosis (programmed cell death).


Cell-Mediated Immunity Memory helper T cells enable the immune system to respond quickly if the same pathogen enters the body again.


HIV HIV is a retrovirus that carries its genetic information in RNA, rather than DNA.

When HIV attacks a cell, it binds to receptor molecules on the cell membrane and inserts its contents into the cell.


Target: T Cells HIV travels through the blood, where it binds to helper T cells—the command centers of the specific immune response.

Once inside the cell, the virus directs the cell to produce many new viruses.

These new viruses are quickly released back into the blood, where they infect new cells.


Preventing HIV Infection This graph shows the increase in cases 13-24-year-olds living with AIDS in the United States.


Causes of Infectious DiseaseWhat causes infectious disease?

Infectious diseases can be caused by viruses, bacteria, fungi, single-celled

eukaryotes (formerly called protists), and parasites.


How Diseases SpreadHow are infectious diseases spread?



Some diseases are spread through coughing, sneezing, physical contact,

or exchange of body fluids. Some diseases are spread through

contaminated water or food. Still other diseases are spread to humans

from infected animals.


Nonspecific DefensesWhat are the body’s nonspecific defenses against pathogens?



Nonspecific defenses include the skin, tears and other secretions, the

inflammatory response, interferons, and fever.


First Line of Defense The most widespread nonspecific defense is the skin.

Very few pathogens can penetrate the layers of dead cells that form the skin’s surface.


First Line of Defense Other nonspecific defenses protect parts of the body that are not covered by skin, such as the mouth, nose, and eyes.

Saliva, mucus, and tears contain lysozyme, an enzyme that breaks down bacterial cell walls.

Mucus in your nose and throat traps pathogens. Then, cilia push the mucous-trapped pathogens away from your lungs.

Stomach secretions destroy many pathogens that are swallowed.


Second Line of Defense If pathogens make it into the body, through a cut in the skin, for example, the body’s second line of defense swings into action.

These mechanisms include the inflammatory response, the actions of interferons, and fever.


Inflammatory Response Many of these white blood cells are phagocytes, which engulf and destroy bacteria.

All this activity around a wound may cause a local rise in temperature. That’s why a wounded area sometimes feels warm.



Infectious diseases can be caused by viruses, bacteria, fungi, single-celled

eukaryotes (formerly called protists), and parasites.


Symbionts vs. Pathogens Most microorganisms that live and grow in the human body are symbionts that are either harmless or actually beneficial.

Yeast and bacteria grow in the mouth and throat without causing trouble.

Bacteria in the large intestine help with digestion and produce vitamins.



Some diseases are spread through coughing, sneezing, physical contact,

or exchange of body fluids. Some diseases are spread through

contaminated water or food. Still other diseases are spread to humans

from infected animals.



Nonspecific defenses include the skin, tears and other secretions, the

inflammatory response, interferons, and fever.


First Line of Defense The most widespread nonspecific defense is the skin.

Very few pathogens can penetrate the layers of dead cells that form the skin’s surface.


Specific Defenses: The Immune SystemWhat is the function of the immune system’s specific defenses?


Specific Defenses: The Immune SystemWhat is the function of the immune system’s specific defenses?

The immune system’s specific defenses distinguish between “self” and

“other,” and they inactivate or kill any foreign substance or cell that enters

the body.


Recognizing “Self” A healthy immune system recognizes all cells and proteins that belong in the body, and treats these cells and proteins as “self.”

This ability to recognize “self” is essential, because the immune system controls powerful cellular and chemical weapons that could cause problems if turned against the body’s own cells.


Recognizing “Nonself” The immune system recognizes foreign organisms and molecules, as “other,” or “nonself.”

Once the immune system recognizes invaders as “others,” it uses cellular and chemical weapons to attack them.

After encountering a specific invader, the immune system “remembers” the invader, enabling a more rapid and effective response if that same pathogen or a similar one attacks again.

This specific recognition, response, and memory are called the immune response.


Antigens Specific immune defenses are triggered by molecules called antigens. An antigen is any foreign substance that can stimulate an immune response.

Typically, antigens are located on the outer surfaces of bacteria, viruses, or parasites.

The immune system responds to antigens by increasing the number of cells that either attack the invaders directly or that produce proteins called antibodies.


Antigens The main role of antibodies is to tag antigens for destruction by immune cells.

Antibodies may be attached to particular immune cells or may be free-floating in plasma.

The body makes up to 10 billion different antibodies.

The shape of each type of antibody allows it to attach to one specific antigen.


Lymphocytes The main working cells of the immune response are B lymphocytes (B cells) and T lymphocytes (T cells).

B cells are produced in, and mature in, red bone marrow.

B cells have embedded antibodies and discover antigens in body fluids.


Lymphocytes T cells are produced in the bone marrow but mature in the thymus—an endocrine gland.

T cells must be presented with an antigen by infected body cells or immune cells that have encountered antigens.


The Immune System in ActionWhat are the body’s specific defenses against pathogens?

The specific immune response has two main styles of action: humoral

immunity and cell-mediated immunity.


Cell-Mediated Immunity Cytotoxic T cells hunt down body cells infected with a particular antigen and kill the cells.

They kill infected cells by puncturing their membranes or initiating apoptosis (programmed cell death).


Cell-Mediated Immunity Memory helper T cells enable the immune system to respond quickly if the same pathogen enters the body again.


Cell-Mediated Immunity Another type of T cell, called suppressor T cells, inhibits the immune response once an infection is under control.

They may also be involved in preventing autoimmune diseases.


Acquired ImmunityHow do vaccines and externally produced antibodies fight disease?


Acquired ImmunityHow do vaccines and externally produced antibodies fight disease?

A vaccine stimulates the immune system with an antigen. The immune

system produces memory B cells and memory T cells that quicken and

strengthen the body’s response to repeated infection.

Antibodies produced against a pathogen by other individuals or animals

can be used to produce temporary immunity.


Public Health and MedicationsHow do public health measures and medications fight disease?


Public Health and MedicationsHow do public health measures and medications fight disease?

Public health measures help prevent disease by monitoring and regulating

food and water supplies, promoting vaccination, and promoting ways that

avoid infection.

Antibiotics can kill bacteria, and some antiviral medications can slow down

viral activity.


New and Re-Emerging DiseasesWhy have patterns of infectious diseases changed?


New and Re-Emerging DiseasesWhy have patterns of infectious diseases changed?

Two major reasons for the emergence of new diseases are the ongoing

merging of human and animal habitats and the increase in the exotic

animal trade.

Misuse of medications has led to the re-emergence of diseases that many

people thought were under control.


When the Immune System “Misfires”How can misguided immune responses cause problems?


When the Immune System “Misfires”How can misguided immune responses cause problems?

A strong immune response to harmless antigens can produce allergies,

asthma, and autoimmune disease.

When the immune system attacks the body’s own cells, it produces an

autoimmune disease.


AllergiesAntigens that cause allergic reactions are called allergens.

Pet dander, dead skin shed from cats and dogs, is a common allergen.


Allergies When allergens enter the body of people affected by allergies, they trigger an inflammatory response by causing mast cells to release histamines.

If this response occurs in the respiratory system, it increases mucus production and causes sneezing, watery eyes, a runny nose, and other irritations.

Drugs called antihistamines help relieve allergy symptoms by counteracting the effects of histamines.


Asthma Allergic reactions in the respiratory system can create a dangerous condition called asthma.

Asthma is a chronic disease in which air passages narrow, causing wheezing, coughing, and difficulty breathing.

Both hereditary and environmental factors influence asthma symptoms.

Asthma attacks can be triggered by respiratory infections, exercise, emotional stress, and certain medications. Other triggers include cold or dry air, pollen, dust, tobacco smoke, pollution, molds, and pet dander.

Lesson Overview Lesson Overview Infectious Disease List of Contageous diseases.

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