Immune SystemImmune System

SC.912.L.14.52 Explain the basic functions SC.912.L.14.52 Explain the basic functions of the human immune system, including of the human immune system, including

specific and nonspecific immune specific and nonspecific immune response, vaccines, and antibioticsresponse, vaccines, and antibiotics

-Students will identify and/or explain the basic -Students will identify and/or explain the basic functions of the human immune system, including functions of the human immune system, including

specific and nonspecific immune responses.specific and nonspecific immune responses.-Students will describe how the human immune system -Students will describe how the human immune system

responds to vaccines and/or antibiotics.responds to vaccines and/or antibiotics.-Students will explain the significance of genetic -Students will explain the significance of genetic

factors, environmental factors, and pathogenic agents factors, environmental factors, and pathogenic agents to health from the perspective of both individual and to health from the perspective of both individual and

public health.public health.

Pathogens and Human IllnessPathogens and Human Illness

Germ theory states that microscopic Germ theory states that microscopic particles cause certain diseases.particles cause certain diseases.– proposed by Louis Pasteurproposed by Louis Pasteur– led to rapid advances in understanding led to rapid advances in understanding

diseasedisease– Koch’s postulates support the theory.Koch’s postulates support the theory.– Disease-causing agents are called pathogensDisease-causing agents are called pathogens

There are different types of There are different types of pathogens.pathogens.

Bacteria are single-celled organisms. Bacteria are single-celled organisms. – cause illness by destroying cells cause illness by destroying cells – release toxic chemicalsrelease toxic chemicals

Viruses are genetic material surrounded Viruses are genetic material surrounded by a protein coat.by a protein coat.– force host cells to make more viruses force host cells to make more viruses – very smallvery small

Fungi can be multicellular or single-celled.Fungi can be multicellular or single-celled.– take nutrients from host cellstake nutrients from host cells– occur in warm and damp placesoccur in warm and damp places

Protozoa are single-celled organisms.Protozoa are single-celled organisms.– use host cells to complete their life cyclesuse host cells to complete their life cycles– take nutrients from host celltake nutrients from host cell

Parasites are multicellular organismsParasites are multicellular organisms– grow and feed on a host grow and feed on a host – possibly kill the hostpossibly kill the host

Pathogens can enter the body in Pathogens can enter the body in different ways.different ways.

Pathogens can be transferred by direct or Pathogens can be transferred by direct or indirect contact.indirect contact.

Indirect contact does not require touching Indirect contact does not require touching an infected individual. an infected individual. – touching an infected touching an infected

surface surface– breathing in infected breathing in infected

air air

Vectors carry a pathogen and transmit it Vectors carry a pathogen and transmit it into healthy cells.into healthy cells.

Direct contact requires touching an Direct contact requires touching an infected individual. Includes: infected individual. Includes: – kissingkissing– sexual intercoursesexual intercourse – hand shaking hand shaking

The immune systems consists The immune systems consists of organs, cells, and molecules of organs, cells, and molecules

that fight infections.that fight infections.

Many body systems protect you Many body systems protect you from pathogens.from pathogens.

The immune system is the body system The immune system is the body system that fights off infection and pathogens.that fights off infection and pathogens.

Many other tissues and systems help the Many other tissues and systems help the immune system.immune system.– Skin is a physical barrier to infection.Skin is a physical barrier to infection.– Mucous membranes trap pathogens entering Mucous membranes trap pathogens entering

the body.the body.– The circulatory system transports immune The circulatory system transports immune

cells.cells.

Cells and proteins fight the body’s Cells and proteins fight the body’s infections.infections.

White blood cells attack infections inside the White blood cells attack infections inside the body.body.– Phagocytes engulf and destroy pathogens. Phagocytes engulf and destroy pathogens. – T cells destroy infected cells.T cells destroy infected cells.– B cells produce antibodies.B cells produce antibodies.

Three types of proteins fight off invading Three types of proteins fight off invading pathogens.pathogens.– Complement proteins weaken pathogen membranes.Complement proteins weaken pathogen membranes.– Antibodies make pathogens ineffective. Antibodies make pathogens ineffective. – Interferons prevent viruses from infecting healthy Interferons prevent viruses from infecting healthy

cells.cells.

Immunity prevents or limits a Immunity prevents or limits a person from getting sick from a person from getting sick from a

pathogen.pathogen.

In all immunity, pathogens are destroyed In all immunity, pathogens are destroyed before you get sick.before you get sick.

Passive immunity occurs without an Passive immunity occurs without an immune response.immune response.– mother’s milkmother’s milk– geneticsgenetics

Active immunity occurs after a specific Active immunity occurs after a specific immune responseimmune response

Immune ResponseImmune Response

The immune system has The immune system has many responses to pathogens many responses to pathogens

and foreign cells.and foreign cells.

Many body systems work to Many body systems work to produce nonspecific responses.produce nonspecific responses.

Nonspecific responses are the same for Nonspecific responses are the same for every pathogen.every pathogen.

In inflammation, blood vessels become In inflammation, blood vessels become leaky.leaky.– white blood cells move toward infection andwhite blood cells move toward infection and

damaged tissue damaged tissue – characterized by swelling, redness, and paincharacterized by swelling, redness, and pain

In fever, body temperature increases.In fever, body temperature increases.– Low fevers stimulate white blood cells to Low fevers stimulate white blood cells to

mature.mature.– High fevers can cause seizure, brain damage, High fevers can cause seizure, brain damage,

and even death.and even death.

Cells of the immune system Cells of the immune system produce specific responses.produce specific responses.

Specific immune responses begin with the Specific immune responses begin with the detection of antigens.detection of antigens.– Antigens are surface proteins on pathogens.Antigens are surface proteins on pathogens.– Each pathogen has a different antigen.Each pathogen has a different antigen.

There are two specific immune responses.There are two specific immune responses.– Cellular immunity uses T cells to destroy Cellular immunity uses T cells to destroy

infected body cells.infected body cells.– Humoral immunity uses B cells to produce Humoral immunity uses B cells to produce

antibodies.antibodies.

Both responses produce memory cells.Both responses produce memory cells.– specialized T and B cellsspecialized T and B cells– provide acquired (active) immunityprovide acquired (active) immunity

The immune system rejects foreign The immune system rejects foreign tissues.tissues.

Tissue rejection occurs in organ or tissue Tissue rejection occurs in organ or tissue transplants.transplants.

Tissue rejection is the result of an immune Tissue rejection is the result of an immune response.response.– immune system detects protein markers on immune system detects protein markers on

the donor tissuethe donor tissue– makes antibodies against the donor’s tissuemakes antibodies against the donor’s tissue

Immunity and TechnologyImmunity and Technology

Living in a clean environment Living in a clean environment and building immunity help and building immunity help

keep a person healthy.keep a person healthy.

Many methods are used to control Many methods are used to control pathogens.pathogens.

Antibiotics and antiseptics cause Antibiotics and antiseptics cause pathogens to burst.pathogens to burst.Antiseptics kill pathogens outside of the Antiseptics kill pathogens outside of the body.body.– do not target specific pathogensdo not target specific pathogens– examples include vinegar and soapexamples include vinegar and soap

Antibiotics kill pathogens inside the body.Antibiotics kill pathogens inside the body.– target one specific bacterium or fungustarget one specific bacterium or fungus– not effective against virusesnot effective against viruses

Antibiotic resistance can cause medicines Antibiotic resistance can cause medicines to become ineffective.to become ineffective.– Some bacteria in a population have genes Some bacteria in a population have genes

that make them immune to antibiotics.that make them immune to antibiotics.– These bacteria spread the gene, making the These bacteria spread the gene, making the

antibiotics useless.antibiotics useless.

Vaccines artificially produce Vaccines artificially produce acquired immunity.acquired immunity.

Vaccines also control pathogens and Vaccines also control pathogens and disease.disease.– given to prevent illnessgiven to prevent illness– contain the antigen of a weakened pathogen contain the antigen of a weakened pathogen

l Vaccination provides immunity.Vaccination provides immunity.– stimulates a specific immune responsestimulates a specific immune response– causes memory cells to be producedcauses memory cells to be produced– allows immune system to respond quickly to allows immune system to respond quickly to

infectioninfection

Overreaction of the Immune Overreaction of the Immune SystemSystem

An overactive immune system An overactive immune system can make the body very can make the body very

unhealthy.unhealthy.

Allergies occur when the immune Allergies occur when the immune system responds to harmless system responds to harmless

antigens.antigens.An allergy is an response to a harmless An allergy is an response to a harmless antigen.antigen.

Allergies are caused by allergens.Allergies are caused by allergens.– Allergens are antigens that cause an allergic Allergens are antigens that cause an allergic

reaction.reaction.– Allergens cause inflammation responses.Allergens cause inflammation responses.

There are many different allergens.There are many different allergens. – food, e.g. peanuts, milk, wheat, etc.food, e.g. peanuts, milk, wheat, etc.– airborne, e.g. pollen, dust mite feces, mold, airborne, e.g. pollen, dust mite feces, mold,

etc.etc.– chemical, e.g. nickel, medicine, bee stings, chemical, e.g. nickel, medicine, bee stings,

etc.etc.

Allergens can cause anaphylaxis.Allergens can cause anaphylaxis.– Anaphylaxis is an extreme inflammation Anaphylaxis is an extreme inflammation

response.response.– Blood vessels and airways become too Blood vessels and airways become too

porous.porous.– If not treated immediately, anaphylaxis can If not treated immediately, anaphylaxis can

cause death.cause death.

In autoimmune diseases, white In autoimmune diseases, white blood cells attack the body’s blood cells attack the body’s

healthy cells.healthy cells.Autoimmune diseases are failures of the Autoimmune diseases are failures of the immune system.immune system.– White blood cells cannot recognize healthy White blood cells cannot recognize healthy

cells.cells.– White blood cells attack healthy body cells.White blood cells attack healthy body cells.– Tissues fail because of attack.Tissues fail because of attack.– There are over 60 autoimmune diseases.There are over 60 autoimmune diseases.