disease Diseaseany condition that impairs the normal functioning of the body Violation of homeostasis Homeostasisability of the body to keep proper internal conditions no matter what is happening outside of it ID: 735598
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Immunity From Disease
Chapter 17Slide2
disease
Disease-any condition that impairs the normal functioning of the body
Violation of homeostasis
Homeostasis-ability of the body to keep proper internal conditions no matter what is happening outside of it
Can be infectious or non-infectious
Infectious diseases are typically caused by pathogens (disease causing agents)
Bacteria,
protists
, fungi, viruses, prions, worms, etc.
Non-infectious diseases are usually the result of errors within the body
Cancer, heart disease, etc.
The line between the two is blurry
Some infectious agents can lead to non-infectious diseases
Viruses can alter the cell cycle and lead to cancerSlide3
Noninfectious Disease
Disease that does not pass from person to person
Can be genetic, environmental, or a combination of the two
Examples:
Sickle Cell Anemia-Hereditary
Osteoporosis-Hereditary and Environmental (poor diet)
Diabetes-Hereditary and dietary
Cancer-Hereditary, environmental and can be infections (HPV (aka genital warts) can increase chance of cervical cancer)Slide4
Edward jenner
Father of Immunology
Developed the first vaccine in 1796
Smallpox was killing millions of people
Injected cowpox, a less harmful yet related disease, into a child
Then injected that child with smallpox
The child did not get infected
Others began using this methodSaved many livesSlide5
John Snow
One of the first to study epidemiology
Study of patterns, causes, and effects of diseases in populations
Studied Cholera spread in London, England during 1854
Cholera is an intestinal disease that causes diarrhea, and can kill with dehydration
Killed nearly 500 people in a certain area of London in a 2-week period
Snow Was able to trace the cause to contaminated water
Initially, people thought that only air carried disease, and that not much could be done He convinced the city to have the pump closed
stopped infections in the areaSlide6
The germ theory of disease
People once thought that spirits caused disease
Holes were drilled in infected people’s heads in an attempt to release the evil spirits
In 1857, French scientist louis Pasteur made the connection between microorganisms and disease
He hypothesized that the disease could be eliminated if the organism was eliminated
Discovered that bacteria could be killed by boiling them
Called pasteurization
A food is heated to a temperature that kills most harmful bacteriaSlide7
Joseph lister
1865
British surgeon
Noticed that about ½ of his patients died from infections, even after successful surgery
Heard about Pasteur’s theory and began doing something drastic
Washing his hands…
The number of infections dropped dramatically (nearly 0)
He also discovered that bacteria can be killed using acidsDeveloped the first disinfecting sprayListerine is named after himSlide8
Robert Koch
1883
German physician
Found that he could make organisms sick by injecting it with pathogens from a sick animal
Came up with 4 conditions that must be met before one can conclude that that a certain pathogen causes a disease
Called Koch’s postulates Slide9
Koch’s postulates
The pathogen must be found in every case the disease is found
The pathogen must be isolated and grown in a pure culture
Healthy organisms infected with the culture must develop the disease
The pathogen must be isolated from the second organism and found to be identical to the firstSlide10Slide11
infectious diseases
Any disease caused by the presence of pathogens in the body
Can be transmitted to others
Contagious-Disease that spreads from one organism to another through close proximity
Does not even require contact
COMMUNICABLE-DISEASE THAT CAN SPREAD FROM PERSON TO PERSON, BUT NOT USUALLY SPREAD THROUGH EVERYDAY CONTACT
Example: herpes Slide12
Spread of infectious diseases
The main source of human pathogens is the human body itself
Carriers-someone who passes the illness on without being infected themselves
Some diseases can be transmitted by other species
Zoonotic diseases
Other diseases can be found in the environment
Dirt, water, etc.Slide13
Transmission of disease
Can be transmitted 4 ways
By direct contact
By an object
Through the air
By an intermediate organism
Called a vectorSlide14
Common Disease-Causing Organisms
Viruses
Cause AIDS, flu, colds, herpes (cold sores and genital)
Bacteria
Cause ear infections, strep throat, pertussis, pneumonia, and many more
Fungi
Cause ringworm/athlete’s foot, and yeast infections including thrush
ProtistsCause malaria (vector: mosquito), African sleeping sickness (vector: fly), toxoplasmosis (vector: cat)
Prions (Infections Proteins)
Cause Bovine Spongiform Encephalopathy (Mad Cow Disease) and its human infection, Creutzfeldt-Jakob Disease Slide15Slide16
First-Line Defenses
of the immune System
Skin, hair, mucus prevent the pathogen from entering
Respiratory system is lined with ciliated cells that can “sweep” pathogen out
Digestive system is acidic and can kill many pathogens
Circulatory system moves pathogens to organs to destroy them, and sends in specialized cells to fight infection (second-line defenders)
Nervous system can raise your body temperature to kill bacteria (fever)Slide17Slide18
Second Line Defenses
of the Immune System
Necessary when pathogens get past the first line of defense
White blood cells “eat” (phagocytize) pathogens, or release chemicals to kill them
Inflammation occurs
Cells release a signal that they are being damaged, which causes blood vessels to widen
Causes the redness and swelling
The bigger vessels allow more WBC to come in and fight the pathogenSlide19Slide20
Third Line Defenses
Of the Immune System
Called specific immunity
Targets only 1 type of pathogen
Antibodies (a substance that neutralizes and kills pathogens) attach to antigens (substances that cause an immune response)
White blood cells, called phagocytes, come in an destroy the pathogen
Once antibodies are produced, they are permanent, and rapidly destroy the pathogen if it tries to enter again
This is why you cannot catch the same cold or flu twice, and why you get vaccines Slide21Slide22
Allergic reactions
If your immune system overreacts to foreign substances (such as dust or pollen), it can release massive amounts of histamines
These cause the symptoms of allergic reactions
Sneezing, increased mucus production, redness, swelling
Your body can also mistake your own cells as foreign and attack your own tissues
Called an autoimmune disorder
arthritis
Can also attack transplanted tissuesSlide23Slide24
Passive and active immunity
Acquired immunity can be active or passive
Passive immunity-Introduction of antibodies produced outside of your body
Antibodies can be transferred from mother to child through placenta
Injecting antibodies from other organism immune to the disease
Occurs with
antivenoms
Active immunity-Your body’s production of antibodies due to exposureCaused by exposure to antigensRecovering from an infection
Vaccines
Injecting dead, weakened, or incomplete portions of pathogens to cause an immune responseSlide25Slide26
A bit about Cancer
Cancer is uncontrolled mitosis
Cells divide out of control
Can be hereditary (breast cancer) or due to environmental factors (lung cancer and skin cancer)
Can strike anybody, regardless of age
Treated with radiation and chemotherapy
Getting better at treating, but not able to cure yet. Hopefully soon…Slide27
Preventing infectious diseases
There are precautions you can take.
Wash your hands after using the bathroom!
With soap and water, for 30 seconds (sing your ABC’s)
Wash your hands before eating
Same rules apply
Hand sanitizer is not as good, but will do if necessary
Avoid sharing foods and beveragesEven with your closest friendsEat a well-balanced diet
Vitamins in fruits and vegetables can help fight illnessSlide28
Top Causes
of Death in the US:
Heart Disease (600,000 deaths per year)
Cancer (580,000 deaths per year)
Respiratory Disease (150,000 deaths per year)
Accidents (130,000 deaths per year)
Stroke (130,000 deaths per year)
For teens:Accidents (50% of teen deaths)Suicide (15% of all deaths)
All other causes (35% of all teen Deaths)Slide29
What can be done?
Avoid the dangers early (Now rather than later)
Heart Disease:
Do not smoke!
Eat a healthy diet (avoid obesity)
Exercise (30+ minutes per day)
Get regular checkups
CancerDo not smoke!Eat a healthy diet (eat your fruits and vegetables) Exercise
Do not tan! Take precautions when in the sun
Respiratory disease
Do not smoke!
Exercise and eat healthySlide30
continued
Accidents
Wear a seatbelt when riding in a car
Be cautions in everyday activities
Stroke
Do not Smoke!
Eat health and exerciseSlide31
For young people
Do not smoke!!!!!!! Don’t ever start. Convince others to quit. Try to limit your exposure to secondhand smoke
Start developing healthy eating habits
Exercise
If you feel depressed, talk to someone! A teacher, a parent, a counselor, anyone. Get help as soon as possible
These problems do not always go away on their own. Sometimes you need help.
Do not bully others! Treat everyone with respect. Be kind. Offer help to anyone who needs it, even of they are not your friend.
If you know someone who needs help and will not seek it, report it to an adult immediately. It is better for them to be mad at you for a bit than to lose them forever.