CHAPTER 15

NOVEMBER 4 & 5, 2010

MEET THE MICROBES• TWO types of Microbes: Bacteria & Viruses -Bacteria:• Can grow and multiply best in environments like: the human body,

warm, dark, moist, and nutrient-rich places. They do best in wounds, where medicines can’t reach them. Ordinary soap makes bacteria slippery so it is easy to wash off with water.

-Tetanus:• Type of bacterium likely to invade a puncture.• Disease is serious & often fatal, even when a person receives

medical attention.• Produces a poison that causes uncontrollable muscle

contractions.• Tetanus kills a person if it reaches the lungs and heart muscles.• Tetanus shots provide immunity against the tetanus poison. Example: Stepping on a nail. Tuberculosis: infects a new person every second of every day and

kills millions each year. Particular worry are new drug-resistant strains that fail to

respond to even the most powerful antibiotics. If patients repeats the mistake of cutting the antibiotics therapy short, the result is a strain of TB against which two antibiotics are useless.

If passed to others the microbes gather more and more resistance.

-Lyme Disease: Passed on by ticks that live on wild deer Starts out as red dot on the skin-weeks to months later you could

feel flulike symptoms; can cause chronic arthritis if left untreated.

MICROBES CONTINUED…. -Viruses: • much smaller • mainly bits of a genetic material that can invade living

cells-even bacterial cells. Using cells equipment viruses reproduce themselves astonishing speeds. Viruses take over the cell’s genetic machinery and force it to serve their purposes-to reproduce more viruses.

• Harm living cells so they cause diseases.• Most people suffer @ least 1 cold (upper respiratory

infection) a year and some come down with the flu (influenza)-highly contagious. Viruses can be to blame.

• Example of reoccurrence of viruses: Chicken pox----Shingles

-Other Pathogens: Fungi (yeasts, molds)-athletes foot; Protozoa-single

celled creatures that cause diarrhea & other illnesses; Pinworms (infect intestines of young children) and head lice are also common and easily cured.

END OF 1ST SECTION QUIZ!

•True/False?

1. PATHOGENS ARE MICROBES THAT CAUSE INFECTIOUS DISEASE.

True

2. BACTERIA AND VIRUSES ARE NOT MICROBES.

False3. MANY KINDS OF

BACTERIA ARE HARMLESS OR EVEN BENEFICIAL. True

4. CERTAIN KINDS OF VIRUSES HAVE BENEFICIAL FUNCTIONS. Fals

e5. BACTERIA CAUSE TETANUS, LYME DISEASE, AND TUBERCULOSIS (TB).

True

6. FUNGI, PROTOZOA, WORMS AND OTHER KINDS OF PARASITES CAN ALSO CAUSE ILLNESS.

True

7. THANKS TO MODERN MEDICINE, TUBERCULOSIS IS NO LONGER A LIFE-THREATENING DISEASE.

False

8. MANY DISEASES, SUCH AS TUBERCULOSIS, MALARIA, PNEUMONIA, AND MANY SEXUALLY TRANSMITTED DISEASES, ARE BECOMING INCREASINGLY DRUG RESISTANT.

True

9. VIRUSES CAUSE DISEASE BY TAKING OVER NORMAL CELLS.

True

10. FUNGI AND MOLDS ARE VIRUSES. Fals

e

PUBLIC DEFENSES AGAINST INFECTIOUS DISEASES

How diseases spread:-Look at it as a cycle; infected person (the

host) contaminates the air, food, or objects, near another, who breathes the air or eats the food or handles the objects and transfers the pathogen to his or her body. Chances are that once inside the pathogen and multiply in the body of the new host, causing diseases.

Example: hepatitis: liver disease; caused by several types of viruses transmitted by infected needs (drug use, tattoos, blood transfusions), by eating raw seafood from contaminated water, and by any contact with body secretions from infected people.

PUBLIC PROGRAMS AGAINST PATHOGENS Public sanitation measures provide some

protection against infections. Government agencies chlorinate public water

supplies and treat sewage to kill pathogens that could contaminate drinking water.

Cholera: dangerous bacterial infection causing violent muscle cramps, severe vomiting and diarrhea, severe water loss, and death. Where there is poor sanitation sick people can pass on diseases.

If you travel to other countries you need to take precautions when drinking the water. Just in case boil water for at least 5 minutes.

Disinfectants: chemicals that kill microbes on surfaces. Bleach is a disinfectant.

Antiseptics: prevent bacterial growth on body surfaces and wounds.

IMMUNIZATIONS Health programs control viral diseases by

destroying animal and insect carries of viruses, and by immunizing house hold pets.

Example: Rabies: a viral disease of the CNS that causes paralysis and death. Health departments require pets be immunized and that infected animals be destroyed.

Vaccine: drug made from altered microbes or their poisons injected or given by mouth to produce immunity. This was made to prevent illnesses in people; this trains the body’s immune system to recognize the active disease agent when it invades. Example: Flu shot.

STATUS OF INFECTIOUS DISEASES Constantly changing U.S. Public Health Service is working its hardest

to control the following infectious diseases; tuberculosis; hepatitis; pneumonia; polio; measles, rubella; mumps; AIDS and hospital infections.

Smallpox: severe viral infection with skin eruptions; once often fatal, it is now believed to be wiped out world wide, thanks to immunizations.

Bubonic plague: bacterial infection causing swollen lymph glands and pneumonia, frequently fatal. Spread by rats in ancient days, has not been wiped out completely.

END OF SECTION 2 QUIZ!

2. A PERSON WHO HAS BEEN INFECTED WITH A VIRUS OR BACTERIA IS CALLED A HOST?

True3. THE CYCLE OF AN EPIDEMIC CAN OFTEN BE STOPPED BY IDENTIFYING THE HOST OF A VIRUS. Tru

e4. PUBLIC SANITATION MEASURES PROVIDE NO PROTECTION AGAINST INFECTIOUS DISEASES.

False5. CHLORINATED WATER IS AN EXAMPLE OF A PUBLIC SANITATION MEASURE.

True

1. THE IMMUNE SYSTEM PROVIDES AN IMPORTANT BARRIER AGAINST INFECTION AND DISEASE.

False

•TRAVELERS IN FOREIGN COUNTRIES SHOULD TAKE PRECAUTIONS AGAINST COMMON LOCAL INFECTIONS, FOR EXAMPLE, BY BOILING DRINKING WATER AND RECEIVING IMMUNIZATIONS.

True8. DISINFECTANTS AND ANTISEPTICS PREVENT BACTERIAL GROWTH.

True

9. SOAP AND WATER HAVE NO EFFECT IN PREVENTING BACTERIAL INFECTION. Fals

e10. IMMUNIZATIONS ARE GIVEN THROUGH THE INJECTION OF A VACCINE.

True

6. CHOLERA IS A DISEASE SPREAD THROUGH RAW MEAT?

False

THE BODY’S DEFENSES & INFECTIOUS DISEASES…

Barriers to Diseases: Skin The Body’s Membranes Components of the Immune System How the Immune System Fights Back Immunity

SKIN AND THE BODY’S MEMBRANES….

Designed to protect the body Produces salty, acidic sweat secretions (most microbes

don’t like salt or acid). Pores that let things out and won’t let microbes in. Scientists found a natural antibiotic protein made skin

that kills microbes.- Punches holes in the bacterial cells causing them to leak. Membranes are also barriers to pathogens; they line the

body’s chambers. More defenses then skin Has a layer of mucus that traps microbes, cilia (hair like

structures) that sweep them out; cells and chemicals of the immune system that destroy them.

Internal membranes fend off great numbers of pathogens every day.

Together the skin and body membranes work to defend against the invading diseases.

COMPONENTS OF THE IMMUNE SYSTEM…. Immune system acts as your own personal bodyguard-

it fights off invaders every day to keep you healthy. No specific location of where your immune system is

at in the body. Bone marrow is an important part of the immune

system-Grows white cells called lymphocytes. Thymus gland another important part-incubates some

of the lymphocytes and changes them into T-cells. T cells recognize the ‘enemy’. B cells-also from lymphocytes-which make antibodies Antibodies: large molecules that serve as the

ammunition to kill off invaders. Antigens: invaders; foreign substance body doesn’t

recognize.

HOW IMMUNE SYSTEM FIGHTS BACK….

Lymphocytes travel in your body fluids. During infection, lymphocytes are drawn to the lymph

nodes and make them swell. When you have a sore throat you can feel the lima

bean shaped lymph nodes that swell up when you are getting a cold.

Histamine: chemical produced by lymphocytes-inflames the site of attack and attracts defenders.-Antihistamine: works by reversing histamines effectsEx. when allergies are bad you would use this type of

medication. Histamines would cause discomfort because you are already inflamed.

If an enemy is spot the T cells sends out an alert-your B cells respond by making antibodies to destroy the invader. There are other antibodies we call scavenger cells that will eat the rest of the invader. Memory cells will ‘remember’ the invader for next time so it will be quickly destroyed.

IMMUNITY…. After the action is over with, only a few

memory and antibodies remain. Memory cells live for many years-responsible

for the immunity that follows many infections or immunizations.

Why don’t people develop immunity to the flu, colds, or cold sores?

RECOGNIZING Page 408…Figure 15-2 Antibiotics: drugs that prevent bacterial growth.

-a person who has developed a bacterial infection can often assist the immune systems defenses by taking antibiotics

-useless against viruses because antibiotics are not cells.

Fever

-think twice before reaching for fever relief meds

Why?

-could actually assist in fighting off infection in your body.

-Fevers help activate the immune system.

END OF SECTION 3 QUIZ!

•THE SKIN TAKES AN ACTIVE PART IN FIGHTING OFF INFECTION AND DISEASES BY RELEASING SALTY, ACIDIC SECRETIONS.

True•THERE IS A NATURAL ANTIBIOTIC PROTEIN MADE BY THE SKIN, WHICH KILLS BACTERIA CELLS BY PUNCHING HOLES IN THEM.

True•THE BODY’S MEMBRANES

HAVE NO DEFENSES AGAINST PATHOGENS. Fals

e•MUCUS, CILIA, AND CHEMICALS ALL WORK IN THE BODY'S MEMBRANES TO DESTROY INVADING PATHOGENS.

True•THE BODY’S IMMUNE SYSTEM

IS LOCATED IN THE LOWER CORTEX OF THE BRAIN. Fals

e

•THE BONE MARROW PRODUCES WHITE BLOOD CELLS CALLED LYMPHOCYTES.

True•T CELLS, LYMPHOCYTES WHICH HAVE

PASSED THROUGH THE THYMUS GLAND, PRODUCE ANTIBODIES.

False

•ANTIBODIES DESTROY INVADERS TO THE BODY KNOWN AS ANTIGENS. Tru

e•THE HUMAN IMMUNE SYSTEM INCLUDES ‘MEMORY CELLS’ THAT REMEMBER THE HISTORY OF AN INFECTION AND ARE RESPONSIBLE FOR IMMUNITY.

True•ANTIBIOTICS ARE AN EFFECTIVE FORM OF TREATMENT FOR VIRAL INFECTIONS. Fals

e

TAKING ACTION……

What are some ways you can take action to prevent infectious disease?

TAKING ACTION…

Keep immunizations up to date. Take care of your immune system Balanced diet Alcohol & other drugs are toxic to immune

system, weakening resistance. Less stress

AIRBORNE INFECTIONS

Prevent viruses being spread through the air by uncovered cough or sneeze.

-Don’t sneeze directly into hand either; inside part of elbow or even shirt.

Try and stay away from people coughing or sneezing carelessly in public places.

If a loved one is sick try to give soothing words from across the room; not giving hugs or kisses.

FOOD POISONING…..

If you have abdominal cramps, headache, vomiting, diarrhea, and a fever you could have food poisoning.

Pathogens that grow in foods can make people sick in two ways; infecting them or poisoning them.

Salmonella: bacterium infect the digestive tract; causing the above symptoms. This illness can be fatal if not treated.

Botulism: often fatal condition with the botulin toxin. This toxin affects the nervous system and needs to be treated by a doctor immediately. This usually comes from canned foods.

PREVENTION…

Insist that food you eat be prepared according to 3 simple rules:

1. Keep hot food hot; if foods have been standing at room temperature for a long time they are probably spoiled.

2. Keep cold food cold; 2hrs or more is too long for cold foods to sit out.

3. Eat only foods that have been prepared and served on clean surfaces and clean hands. Avoid foods served with utensils that previously touched raw meats or are dirty from others.

Toss out any foods that have reached their expiration date; if cans are bulging or appear to be leaking.

END OF SECTION 4 QUIZ!

•IMMUNIZATION IS A VITAL STEP IN PREVENTING MANY DISEASES AND INFECTION.

True

•A BALANCED DIET STRENGTHENS THE IMMUNE SYSTEM.

True

•ALCOHOL HAS NO EFFECT ON THE IMMUNE SYSTEM. Fals

e•PHYSICAL ACTIVITY BOOSTS THE IMMUNE SYSTEM. True•STRESS STIMULATES THE IMMUNE SYSTEM AND HELPS TO PREVENT INFECTION.

False

•YOU CAN MINIMIZE THE RISK OF AIRBORNE INFECTION BY DISTANCING YOURSELF FROM A COUGHING OR SNEEZING PERSON.

True

•FREQUENTLY WASHING YOUR HANDS IS ANOTHER WAY TO MINIMIZE THE RISK OF INFECTION. True•FOOD POISONING IS AN UNLIKELY CAUSE OF INTESTINAL DISTRESS. Fals

e•PATHOGENS HIDING IN FOOD CAN CAUSE ILLNESS BY INFECTING THE DIGESTIVE TRACT OF BY POISONING THE FOOD ITSELF. True•SPOILED FOOD IS ALWAYS REVEALED BY AN ODD TASTE AND SMELL.

False