+ immune system and disease chapter 35. + what are the basics? homeostasis homeostasis is the...
TRANSCRIPT
+What are the basics?
Homeostasis is the ability of an organism to maintain a stable internal environment.
Diseases can disrupt this stability.
Your immune system is the organ system that protects your body from disease.
Your body has three different lines of defense against pathogens, or disease causing agents.
+Infectious Diseases
Occurs when pathogens cause a physiological changes that disrupt normal body functions
Pathogens are disease-causing agents
Infectious diseases can be caused by:Viruses (non-living)BacteriaFungiProtistsParasites
+How do diseases spread ?
Coughing, Sneezing, Physical Contact Mostly infect the nose, throat and respiratory
tract
Exchange of body fluids Most sexually transmitted disease
Contaminated water/food Affect the digestive tract Diarrhea is one common symptom
Infected animals Mad cow disease, SARS, West Nile virus, bird
flu, etc
+What are the two types of immune defense?
The immune system includes two general categories of defense mechanisms against infection.
Nonspecific defenses guard against infections by keeping most things out of the body.
Specific defenses track down harmful pathogens that have managed to break throughthe body’s nonspecific defenses.
+The Body’s Defense Systems
INNATE Immunity
1st and 2nd lines of defense
1st defense: Skin Saliva, mucus, tears
2nd defense: Inflammatory
response
ACQUIRED Immunity
3rd line of defense
The body distinguishes between “self” and “foreigner”
Respond to particular pathogens
Non-Specific Defense Specific Defense
+Question Break:
Why do you think the 1st and 2nd defense are called innate and the
3rd defense called acquired?
HINT: Innate means “instinctual” or “born with” & acquired means to
obtain
+1st Line of Defense: Barriers to Infection
To cause disease, a pathogenmust invade the body.
Your body has barriers to keep this pathogens out.
Skin provides a protective barrier.
Mucous membranes line up interiorsurfaces that come into contact withthe environment.
Pathogens that are swallowedare likely to be destroyed byyour stomach acids.
Sweat and tears contains salts, acids,and enzymes that help kill pathogensin your skin and eyes.
+2nd Line of Defense: Inflammatory Response
The inflammatory response is the body’s responseto tissue damage.
As soon as pathogen enters your body, damaged tissue releases chemical signal (histamines).
Blood vessels expand. What is a consequence of this?
Plasma carries macrophages that engulf and destroy pathogens during phagocytosis
If infection persists, body may increasetemperatureresulting in a fever.Why?
+3rd Line of Defense: Immune Response (Acquired immunity) The immune response attacks specific
pathogens using specialized cells and proteins
Leukocytes: white blood cells (2 types):
1. T cells are white blood cells that attack and kill harmful bacteria.
2. B cells are white blood cells that make antibodies.
+Signaling the problem
An antigen is any foreign substance in the body and stimulates an immune response
An antibody is a Y-shaped protein that attaches to a specific antigen,
bind to the pathogen's membrane proteins
Acts as a flag for destruction weaken the pathogen’s membrane Made by B-cells
+Immune response has 2 styles of Action
1. Humoral ResponseSignaling responseActivates production of B-cells
2. Cell-Mediated ResponseDestruction responseActivates T-cell response
+The Story of Your Body’s Soldiers
An antigen of a pathogen attaches to an antibody of a B-cell
Helper T-cells activate B cells to grow and divide rapidly into1. Plasma B-cells
2. Memory B-cells (secondary response)
Plasma B-cells release more antibodies that mark antigens for destruction
+The Story of Your Body’s Soldiers
Helper T-cells bind to antigen and are activated to go and activate:1. More helper T-cells- to activate B cells
2. Cytotoxic T-cells
3. Produce Memory T-cells (secondary Response)
Cytotoxic T-cells Bind to infected cells containing antigen destroy infected cell
Puncture membrane Initiate apoptosis (cell suicide)
+Secondary Response- Memory B and T cells
The next time the same pathogen enters the body, the immune response is much
faster at fighting it because of the memory B and T cells
Memory B and T cells are already “trained” with the antibodies produced in the
primary response
Immunity: ability to resist diseasePossible because of memory B and T cells
+Bellringer- Review Specific Immune Response
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter22/animation__the_immune_response.html
http://www.sciencelearn.org.nz/Contexts/Fighting-Infection/Sci-Media/Animations-and-Interactives/The-immune-system
http://hippocampus.org/HippoCampus/Biology?loadLeftClass=CourseCombination&loadLeftId=9&loadTopicId=354
+How do we fight infectious disease when our immune system isn’t strong enough on its own?
CASE STUDY: Smallpox and Chicken Pox
Smallpox was once found throughout the world.
Caused illness and death wherever it occurred.
Smallpox spreads easily from one person to another.
People were once vaccinated against this disease.
+Case Study: Small Pox
The United States stopped giving the smallpox vaccine in 1972.
In 1980, the World Health Organization (WHO) recommended that all countries stop vaccinating for smallpox.
The vaccine is no longer given to the general public because the virus has been wiped out. Or has it?
+The last naturally occurring case of smallpox was diagnosed on 26 October 1977.
In ordinary type smallpox the bumps are filled with a thick, opaque fluid and often have a depression or dimple in the center.
Acquired ImmunityMore than 200 years
ago, the English physician Edward Jenner wondered if it might be possible to produce immunity against smallpox.
Jenner knew that people who had been affected by a mild disease called cowpox developed an immunity to smallpox.
Acquired ImmunityJenner took fluid from
one of the sores of a cowpox patient and put the fluid into a small cut that he made on the arm of a young farm boy named Jamie Phillips.
Two months later, he injected Jamie with fluid from a smallpox infection and …
The rest is history.
+Active Immunity and Vaccination
A Vaccination is the injection of a weakened or a similar but less dangerous form of a pathogenStimulates immune system with an antigen Body produces memory B and T cellsQuicken and Strengthen immune response
This is an example of Active ImmunityNatural exposure to antigen Deliberate exposure to antigen (Vaccine)
+ Vaccines Save Lives By Preventing Disease
Vaccine’s prevent the infection of a pathogen
There are vaccines for more than 20 serious human diseases
Not every disease has a vaccine
that we have discovered
+Passive Immunity
Diseases can be prevented also by injecting antibodies produced by other animals or individualsThis gives an individual temporary immunity Immune system eventually destroys foreign
antibody
Can also occurNaturally (through mother’s breast milk or
placental transfusion)Deliberately (injection)
+See the Difference?
Active Immunity
Inject a pathogen
Long-term immunity
Strengthens immune system
Passive Immunity
Inject antibodies
Short-term immunity
Temporarily defeats pathogen
Both can occur naturally or deliberately
+Antibiotics
Antibiotics drugs are those that can kill bacteria without harming the host Ex: Penicillium
They have NO effect on viruses Why? (hint- break down the word)
There are, however, antiviral drugs that can slow down viral activity Viruses are very difficult to get rid of Some never are able to leave your body
+New and Re-emerging Diseases
Why are infectious diseases changing? New Diseases coming from
ongoing merging of human and animal habitats
Misuse of medications Evolving resistance to drugs
http://wps.prenhall.com/esm_freeman_biosci_1/0,6452,499512-,00.html
+Misguided Immune Response
Sometimes an strong immune response to a harmless antigen will produce Allergies Asthma Autoimmune diseases
Harmless particles: pollen, dust mites, mold, pet dander, their own cells
+Allergies
Allergens: antigens that cause allergies
When an allergen enters the body, the inflammatory response is triggeredMast cells release histaminesSymptoms: rashes, sneezing,
watery eyes, runny nose
Antihistamines are drugs that relieve allergy symptoms
+AsthmaAllergic reaction in the respiratory
system Air passages narrow Causing short breath, wheezing,
coughing
Triggered by: Genetic predisposition Environmental factors Respiratory infections Exercise Emotional distress Cold/dry air Smoke, dust, pet dander, etc
+Autoimmune diseasesSometimes diseases occur where the
immune system fails to properly recognize “self” Attacks the own body’s cells or
compounds Thinks they are pathogens
Examples: Type I diabetes Rheumatoid Arthritis Lupus
Some treatments can alleviate symptoms and some suppress the immune response Sadly, there are no cures
+HIV/AIDS- Human Immunodeficiency
HIV- Human Immunodeficiency Virus The CAUSE of AIDS Known as a retrovirus Attacks the Helper T-Cells Becomes difficult for the immune
response to defend against diseases and pathogens
AIDS- Acquired Immunodeficiency Syndrome When the amount of T-cells in the
body is reduced to less than 1/6 normal count
+HIV and AIDS attacks the immune system
HIV/AIDS is not actually the killer itself directlyThe disease debilitates the
immune systemThe immune system can no
longer efficiently respond to pathogens it normally fights off
Causes opportunistic diseases- diseases that attack a person with a weakened immune system
+Spread and Prevention
Only transmitted through contact with Infected blood Semen Vaginal Secretions Breast milk
4 main ways it spreads:1. Sexual intercourse2. Shared needles3. Blood contact4. Mother-to-child (during
pregnancy, birth, breast-feeding
+Spread and Prevention
No-risk behavior includesSexual abstinence Intravenous drug-use abstinence
Many people do not know they have HIV/AIDS because they have not progressed far enough in the disease This is why it is so important to KNOW
a potential sexual partner EVERYONE being tested is essential to
stop the spread
+There is NO cure.
Currently there s no cure for aids
Only drugs that can help survive for some yearsVERY expensive
DEADLY misconception Just because there are
treatments, some people now believe AIDS is not serious
DEAD WRONGhttp://www.whitehouse.gov/admin
istration/eop/onap/nhas