Unit 10 The Human BodyUnit 10 The Human Body

Ch. 40 The Immune System & Disease

Ch. 40 The Immune System & Disease

Infectious DiseaseInfectious Disease

Disease - any change, other than an injury, that disrupts homeostasis

Some diseases are produced by agents like: bacteria, viruses, & fungi

Disease - any change, other than an injury, that disrupts homeostasis

Some diseases are produced by agents like: bacteria, viruses, & fungi

PathogensPathogens

Pathogens - disease-causing agents Diseases caused by pathogens are

generally infectious disease

Pathogens - disease-causing agents Diseases caused by pathogens are

generally infectious disease

The Germ Theory of DiseaseThe Germ Theory of Disease

For thousands of years, people believed that diseases were caused by curses, evil spirits, or night vapors

Chemist, Louis Pasteur & bacteriologist, Robert Koch, concluded that diseases were caused by different types of microorganisms, called germs

For thousands of years, people believed that diseases were caused by curses, evil spirits, or night vapors

Chemist, Louis Pasteur & bacteriologist, Robert Koch, concluded that diseases were caused by different types of microorganisms, called germs

Koch’s PostulatesKoch’s Postulates

1. The pathogen should always be found in the body of a sick organism, not in a healthy one

2. The pathogen must be isolated & grown in the lab in pure culture

1. The pathogen should always be found in the body of a sick organism, not in a healthy one

2. The pathogen must be isolated & grown in the lab in pure culture

Koch’s PostulatesKoch’s Postulates

3. When the cultured pathogens are placed in a new host, they should cause the same disease that infected the original host

4. The injected pathogen should be isolated from the second host. It should be identical to the original pathogen.

3. When the cultured pathogens are placed in a new host, they should cause the same disease that infected the original host

4. The injected pathogen should be isolated from the second host. It should be identical to the original pathogen.

Agents of DiseaseAgents of Disease

Some pathogens, including viruses & some bacteria, destroy cells as they grow

Other bacteria release toxins that harm an organism

Some pathogens, including viruses & some bacteria, destroy cells as they grow

Other bacteria release toxins that harm an organism

Agents of DiseaseAgents of Disease

Still others, especially parasitic worms, produce sickness when they block the flow of blood, remove nutrients from the digestive system, & disrupt other bodily functions

Still others, especially parasitic worms, produce sickness when they block the flow of blood, remove nutrients from the digestive system, & disrupt other bodily functions

How Diseases Are SpreadHow Diseases Are Spread

Some infectious diseases are spread from 1 person to another through coughing, sneezing, or physical contact

Other infectious diseases are spread through contaminated water or food

Some infectious diseases are spread from 1 person to another through coughing, sneezing, or physical contact

Other infectious diseases are spread through contaminated water or food

How Diseases Are SpreadHow Diseases Are Spread

Still others are spread by infected animals Vectors - animals that carry pathogens from

person to person

Still others are spread by infected animals Vectors - animals that carry pathogens from

person to person

Fighting Infectious DiseasesFighting Infectious Diseases

Antibiotics - compounds that kill bacteria without harming the cells of the human or animal hosts

Antibiotics - compounds that kill bacteria without harming the cells of the human or animal hosts

The Immune SystemThe Immune System

The function of the immune system, is to fight infection through the production of cells that inactivate foreign substances or cells - immunity

The immune system includes 2 general categories of defense mechanisms: nonspecific & specific defenses

The function of the immune system, is to fight infection through the production of cells that inactivate foreign substances or cells - immunity

The immune system includes 2 general categories of defense mechanisms: nonspecific & specific defenses

Nonspecific DefensesNonspecific Defenses

Nonspecific defenses do not discriminate between 1 threat & another

These defenses include physical & chemical barriers

Nonspecific defenses do not discriminate between 1 threat & another

These defenses include physical & chemical barriers

Nonspecific DefensesNonspecific Defenses

First Line of Defense: The function is to keep pathogens out of the

body This role is carried out by skin, mucus, sweat,

& tears Your body’s most important

nonspecific defense is the skin

First Line of Defense: The function is to keep pathogens out of the

body This role is carried out by skin, mucus, sweat,

& tears Your body’s most important

nonspecific defense is the skin

Nonspecific DefensesNonspecific Defenses

Second Line of Defense: If pathogens enter your body, they multiply

quickly, releasing toxins into your tissues When this happens, it activates the

inflammatory response Inflammatory response - a reaction to tissue

damage caused by injury or infection

Second Line of Defense: If pathogens enter your body, they multiply

quickly, releasing toxins into your tissues When this happens, it activates the

inflammatory response Inflammatory response - a reaction to tissue

damage caused by injury or infection

Nonspecific DefensesNonspecific Defenses

Second Line of Defense: When pathogens enter the body, phagocytes

(white blood cells), move into the area & engulf (eat) the pathogens

Second Line of Defense: When pathogens enter the body, phagocytes

(white blood cells), move into the area & engulf (eat) the pathogens

Inflammatory ResponseInflammatory Response

Nonspecific DefensesNonspecific Defenses

Second Line of Defense: The immune system also releases chemicals

that increase the core body temp. - Fever An elevated body temp. slows down or stops

the growth of some pathogens Fever & increased # of WBC’s indicates an

infection

Second Line of Defense: The immune system also releases chemicals

that increase the core body temp. - Fever An elevated body temp. slows down or stops

the growth of some pathogens Fever & increased # of WBC’s indicates an

infection

Nonspecific DefensesNonspecific Defenses

Second Line of Defense: Sometimes, virus-infected cells produce a

group of proteins that help other cells resist viral infection

Interferons - “interfere” with the growth of viruses; they inhibit the synthesis of viral proteins in infected cells & help block viral replication

Second Line of Defense: Sometimes, virus-infected cells produce a

group of proteins that help other cells resist viral infection

Interferons - “interfere” with the growth of viruses; they inhibit the synthesis of viral proteins in infected cells & help block viral replication

Specific DefensesSpecific Defenses

If a pathogen gets past the body’s nonspecific defenses, the immune system reacts with specific defenses that attack that particular disease-causing agent - Immune response

If a pathogen gets past the body’s nonspecific defenses, the immune system reacts with specific defenses that attack that particular disease-causing agent - Immune response

Specific DefensesSpecific Defenses

Antigen - a substance that triggers this response, includes: viruses, bacteria, & other pathogens

2 types of lymphocytes recognize specific antigens: B lymphocytes

(B cells) & T lymphocytes (T cells)

Antigen - a substance that triggers this response, includes: viruses, bacteria, & other pathogens

2 types of lymphocytes recognize specific antigens: B lymphocytes

(B cells) & T lymphocytes (T cells)

Specific DefensesSpecific Defenses

B cells provide immunity against antigens & pathogens in the body fluids - Humoral immunity

T cells defend against abnormal cells & pathogens inside living cells - Cell-mediated immunity

B cells provide immunity against antigens & pathogens in the body fluids - Humoral immunity

T cells defend against abnormal cells & pathogens inside living cells - Cell-mediated immunity

Specific DefensesSpecific Defenses

Humoral Immunity: When a pathogen invades the body, it is

recognized by B cells These B cells grow & divide rapidly, producing

large #’s of plasma cells & memory B cells

Humoral Immunity: When a pathogen invades the body, it is

recognized by B cells These B cells grow & divide rapidly, producing

large #’s of plasma cells & memory B cells

Specific DefensesSpecific Defenses

Humoral Immunity: Plasma cells release antibodies Antibodies - proteins that recognize & bind to

antigens, they are carried in the bloodstream to attack the pathogen causing the infection

Once the body has been exposed, memory B cells remain capable of producing antibodies specific to that pathogen

Humoral Immunity: Plasma cells release antibodies Antibodies - proteins that recognize & bind to

antigens, they are carried in the bloodstream to attack the pathogen causing the infection

Once the body has been exposed, memory B cells remain capable of producing antibodies specific to that pathogen

Specific DefensesSpecific Defenses

Cell-mediated Response: T cells provide defense against abnormal

cells & pathogens inside living cells

Cell-mediated Response: T cells provide defense against abnormal

cells & pathogens inside living cells

Specific DefensesSpecific Defenses

Although killer T cells are helpful in the immune system, they make acceptance of organ transplants difficult

Your immune system damages & destroys the transplanted organ

The process is known as rejection

Although killer T cells are helpful in the immune system, they make acceptance of organ transplants difficult

Your immune system damages & destroys the transplanted organ

The process is known as rejection

Acquired ImmunityAcquired Immunity

Vaccination - the injection of a weakened pathogen to produce immunity

Active immunity - immunity produced by the body’s reaction to a vaccine

Passive immunity - when antibodies produced by other animals are injected into the bloodstream

Vaccination - the injection of a weakened pathogen to produce immunity

Active immunity - immunity produced by the body’s reaction to a vaccine

Passive immunity - when antibodies produced by other animals are injected into the bloodstream

Acquired ImmunityAcquired Immunity

Active Immunity: It appears after exposure to an antigen, as a

result of the immune response Active immunity may develop as a result of

natural exposure to an antigen (fighting an infection) or from deliberate exposure to the antigen (through a vaccine)

Active Immunity: It appears after exposure to an antigen, as a

result of the immune response Active immunity may develop as a result of

natural exposure to an antigen (fighting an infection) or from deliberate exposure to the antigen (through a vaccine)

Acquired ImmunityAcquired Immunity

Passive Immunity: It only lasts a short time because eventually, the

body destroys the foreign antibodies Like active immunity, it may develop naturally

or by deliberate exposure

Passive Immunity: It only lasts a short time because eventually, the

body destroys the foreign antibodies Like active immunity, it may develop naturally

or by deliberate exposure

Acquired ImmunityAcquired Immunity

Passive Immunity: 1 kind of natural immunity occurs when the

mother passes antibodies to the fetus through the placenta, or through breast milk

Passive Immunity: 1 kind of natural immunity occurs when the

mother passes antibodies to the fetus through the placenta, or through breast milk

Immune System DisordersImmune System Disorders

There are 3 different types of immune system disorders: allergies, autoimmune diseases, & immunodeficiency diseases

There are 3 different types of immune system disorders: allergies, autoimmune diseases, & immunodeficiency diseases

AllergiesAllergies

Allergies - overreactions of the immune system to antigens

Common allergies include: pollen, dust, mold, & bee stings

Allergies - overreactions of the immune system to antigens

Common allergies include: pollen, dust, mold, & bee stings

AllergiesAllergies

When allergy-causing antigens enter the body, they attach themselves to cells that initiate the inflammatory response

Those cells release chemicals called histamines

When allergy-causing antigens enter the body, they attach themselves to cells that initiate the inflammatory response

Those cells release chemicals called histamines

AllergiesAllergies

Histamines - chemicals that increase the flow of blood & fluids to the surrounding area

They also increase mucus production, resulting in sneezing, watery eyes, runny nose, & other irritations

Histamines - chemicals that increase the flow of blood & fluids to the surrounding area

They also increase mucus production, resulting in sneezing, watery eyes, runny nose, & other irritations

AsthmaAsthma

Asthma - a chronic respiratory disease where the air passages become narrower than normal

It causes wheezing, coughing, & difficulty in breathing

Asthma attacks can be triggered by infections, exercise, stress, etc.

Asthma - a chronic respiratory disease where the air passages become narrower than normal

It causes wheezing, coughing, & difficulty in breathing

Asthma attacks can be triggered by infections, exercise, stress, etc.

Autoimmune DiseasesAutoimmune Diseases

Autoimmune disease - when the immune system makes a mistake & attacks the body’s own cells

Multiple sclerosis is an example where antibodies destroy the functions of the neurons in the brain & spinal cord

Autoimmune disease - when the immune system makes a mistake & attacks the body’s own cells

Multiple sclerosis is an example where antibodies destroy the functions of the neurons in the brain & spinal cord

AIDS, an Immunodeficiency Disease

AIDS, an Immunodeficiency Disease

1 type of immunodeficiency disease, the immune system fails to develop normally

The 2nd type of immunodeficiency disease is AIDS

1 type of immunodeficiency disease, the immune system fails to develop normally

The 2nd type of immunodeficiency disease is AIDS

AIDS, an Immunodeficiency Disease

AIDS, an Immunodeficiency Disease

AIDS results from a viral infection (HIV) that destroys helper T cells

As the # of helper T cells declines, the normal immune response breaks down

When a person has AIDS, they die from the inability to fight off infection, like the flu, a cold, etc.

AIDS results from a viral infection (HIV) that destroys helper T cells

As the # of helper T cells declines, the normal immune response breaks down

When a person has AIDS, they die from the inability to fight off infection, like the flu, a cold, etc.

AIDS, an Immunodeficiency Disease

AIDS, an Immunodeficiency Disease

AIDS - Acquired ImmunoDeficiency Syndrome

HIV - Human Immunodeficiency Virus (causes AIDS)

AIDS - Acquired ImmunoDeficiency Syndrome

HIV - Human Immunodeficiency Virus (causes AIDS)

HIV InfectionHIV Infection

AIDS, an Immunodeficiency Disease

AIDS, an Immunodeficiency Disease

There are 4 main ways HIV can be transmitted: 1. Sexual intercourse with an infected

individual 2. Shared needles or syringes 3. Contact with blood or blood products 4. Infected mother to child, during pregnancy,

birth, or breast-feeding

There are 4 main ways HIV can be transmitted: 1. Sexual intercourse with an infected

individual 2. Shared needles or syringes 3. Contact with blood or blood products 4. Infected mother to child, during pregnancy,

birth, or breast-feeding

AIDS, an Immunodeficiency Disease

AIDS, an Immunodeficiency Disease

The only no-risk behavior with respect to HIV & AIDS is abstinence (no sex)

At the present time, there is no cure for AIDS

The only no-risk behavior with respect to HIV & AIDS is abstinence (no sex)

At the present time, there is no cure for AIDS

The Environment & Your HealthThe Environment & Your Health

Risk factor - factors that have potential to affect health in a negative way

Environmental factors that can affect your health include air & water quality, poisonous wastes in landfills, & exposure to solar radiation

Risk factor - factors that have potential to affect health in a negative way

Environmental factors that can affect your health include air & water quality, poisonous wastes in landfills, & exposure to solar radiation

Air QualityAir Quality

Carbon monoxide is found in automobile exhaust & cigarette smoke

When carbon monoxide is inhaled, it prevents hemoglobin from carrying oxygen

Carbon monoxide is found in automobile exhaust & cigarette smoke

When carbon monoxide is inhaled, it prevents hemoglobin from carrying oxygen

Air QualityAir Quality

Lead is a particulate found in the air that can poison the liver, kidneys, & nervous system

Lead poisoning in babies & young children can result in slow mental development

Lead is a particulate found in the air that can poison the liver, kidneys, & nervous system

Lead poisoning in babies & young children can result in slow mental development

Air QualityAir Quality

Asbestos is another particulate that may be carried in the air

It was commonly used for insulation, & when inhaled, it can cause lung cancer

Asbestos is another particulate that may be carried in the air

It was commonly used for insulation, & when inhaled, it can cause lung cancer

Water QualityWater Quality

Water can carry biological & chemical pollutants

Biological pollutants, like human & animal wastes, can contain bacteria or viruses that cause cramps, vomiting, diarrhea, or diseases like hepatitis or cholera

Water can carry biological & chemical pollutants

Biological pollutants, like human & animal wastes, can contain bacteria or viruses that cause cramps, vomiting, diarrhea, or diseases like hepatitis or cholera

Water QualityWater Quality

Some chemical pollutants cause organ damage

Others interfere with development of organs & tissues, causing birth defects

Still others can damage DNA, causing normal cells to become cancerous

Some chemical pollutants cause organ damage

Others interfere with development of organs & tissues, causing birth defects

Still others can damage DNA, causing normal cells to become cancerous

BioterrorismBioterrorism

Bioterrorism involves treating pathogens to maximize their ability to infect & cause disease

Anthrax is a disease common in cattle-ranching areas, not life-threatening

The spores can be treated to be spread in the air & inhaled, producing a fatal infection

Bioterrorism involves treating pathogens to maximize their ability to infect & cause disease

Anthrax is a disease common in cattle-ranching areas, not life-threatening

The spores can be treated to be spread in the air & inhaled, producing a fatal infection

CancerCancer

Cancer is a life-threatening disease where cells multiply uncontrollably & destroy healthy tissue

Cancer cells are the bodies own cells

Cancer is a life-threatening disease where cells multiply uncontrollably & destroy healthy tissue

Cancer cells are the bodies own cells

CancerCancer

Cancer begins when cells grow & reproduce uncontrollably, resulting in a tumor

Tumor - the formation of a mass of growing tissue

Cancer begins when cells grow & reproduce uncontrollably, resulting in a tumor

Tumor - the formation of a mass of growing tissue

CancerCancer

Benign tumors are NOT cancerous Malignant tumors are cancerous, & are

capable of invading & destroying surrounding healthy tissue

Benign tumors are NOT cancerous Malignant tumors are cancerous, & are

capable of invading & destroying surrounding healthy tissue

CancerCancer

Cancers are caused by defects in the genes that regulate cell growth & division

The genetic defects may be inherited, caused by viruses, or result from mutations in DNA that are produced by chemicals, radiation, or occur spontaneously

Cancers are caused by defects in the genes that regulate cell growth & division

The genetic defects may be inherited, caused by viruses, or result from mutations in DNA that are produced by chemicals, radiation, or occur spontaneously

CancerCancer

Carcinogens - chemical compounds that are known to cause cancer by triggering mutations in the DNA of normal cells

Some of the most powerful chemical carcinogens are found in tobacco smoke

Carcinogens - chemical compounds that are known to cause cancer by triggering mutations in the DNA of normal cells

Some of the most powerful chemical carcinogens are found in tobacco smoke

CancerCancer

The best way to fight cancer is by protecting your DNA from agents that cause cancer

Regular exercise & a balanced diet, regular checkups, self-examinations, etc., can all help reduce your risk

The best way to fight cancer is by protecting your DNA from agents that cause cancer

Regular exercise & a balanced diet, regular checkups, self-examinations, etc., can all help reduce your risk

Maintaining HealthMaintaining Health

To keep your immune system working efficiently, practice behaviors that reduce your exposure to pathogens & maintain overall good health

Healthful behaviors include eating a healthy diet, exercise, get plenty of rest, abstaining from harmful activities, & have regular checkups

To keep your immune system working efficiently, practice behaviors that reduce your exposure to pathogens & maintain overall good health

Healthful behaviors include eating a healthy diet, exercise, get plenty of rest, abstaining from harmful activities, & have regular checkups