Download The Immune System Mr. Alvarez December 17, 2013

The Immune System
Mr. Alvarez
December 17, 2013
Do Now: Answer the following on a
sheet of loose leaf paper
1. Blood returning to the heart from the
Kidneys goes to which Heart Chamber?
2. What is the difference between Pulmonary
and Systemic Circulation?
3. When a person exercises, why does the heart
pump faster?
Infectious Disease
Disease- Any change, other than injury that
disrupts the normal functions of the body
Causes can be infectious agents
Example: bacteria, viruses and fungi
Causes can be environmental
Example: Cigarette smoke, Pollution
Causes can be Genetic
Example: Hemophilia
Pathogens
Pathogens- Disease causing agents
Pathogens are a threat to Homeostasis
Agents of Disease
Viruses- Tiny Particles that invade and
replicate within living cells
Can infect nearly every type of organism including
plants, animals, and bacteria
Example: Common cold, influenza, smallpox, warts
Bacteria
• Bacteria- Cause harm by either breaking down
the tissues of the host organism for food, or
by releasing toxins that harm the body
– Example: Streptococcus infections, diphtheria,
botulism and anthrax
Fungi
Fungi- Kingdom composed of heterotrophs;
many obtain energy and nutrients from dead
organic matter
Tinea- Responsible for Athlete’s Foot
Worms
Worms-Flatworms and Roundworms usually
responsible for many digestive system
diseases
Fighting Infectious Diseases
Antibiotics- compounds that kill bacteria
without harming the cells of the human or
animal hosts
Usually work by interfering with the cellular
processes of microorganisms
ANTIBIOTICS HAVE NO EFFECT ON VIRUSES
How was Antibiotics Discovered?
• Penicillin was discovered by accident when
Scottish Bacteriologist Alexander Fleming left
dirty Petri Dishes out in the lab when he went
on vacation in 1928
Over-the-Counter-Drugs
• Over the counter drugs treat symptoms of
disease.
– They make you FEEL better, not GET better
• Best treatment for most infectious diseases
includes rest, well-balanced diet and plenty of
fluids
The Immune System
• Immune System- Fights infection through the
production of cells that inactivate foreign
substances or cells.
Immunity- ability of the body to resist a specific
pathogen
First line of defense
• Your body’s most important nonspecific
defense is the skin
– Sweat glands in skin produce acidic environment
– Nose and throat have mucus and cilia
– Stomach has acid and enzymes
Second Line of Defense
Inflammatory Response- nonspecific defense
reaction to tissue damage caused by injury or
infection; swelling
 White Blood Cells (WBC’s) rush to the site and
engulf pathogens
Phagocytosis- process in which cells surround and
engulf large particles and take them into the cell
Fever
• Fever- Elevated body temperature
– Slows down or stops the growth of pathogens
– Increases heart rate so white blood cells get to the
site of infection faster
Specific Defenses
• Immune Response- specific cells are
programmed to fight specific diseases
– Antigen- Substance that triggers an immune
response
– Antibodies- Proteins that recognize and bind to
antigens
• Shape makes it possible for Antibody to recognize
Antigen
Vaccinations
• Vaccination- The injection of a weakened form
of a pathogen to produce immunity
– Purpose is to create antibodies before the body
becomes infected
– Immune System practices against weakened form
Immune System Disorders
• Allergies- Overreaction of the immune system
to antigens
– Example: Pollen, dust, mold, bee stings, peanuts
Asthma
• Asthma- a chronic respiratory disease in which
the air passages become narrower than
normal
– Cause wheezing, coughing and difficulty breathing
– Heredity and/or Environmental
– Can be life-threatening
– Can lead to permanent damage or destruction of
lung tissue
Autoimmune Diseases
• Autoimmune Diseases- When the Immune
System makes a mistake and attacks the
body’s own cells
– Example: Type 1 Diabetes, Rheumatoid Arthritis,
Multiple Sclerosis (MS)
AIDS
• AIDS- Acquired Immune Deficiency Syndrome
– Caused by HIV- Human Immunodeficiency Virus
• HIV virus is deadly for two reasons
1. It evades the defenses of the immune system
2. It attacks key cells in the immune system,
destroying the body’s defenses and leaving the
body with no protection against other
pathogens
Transmission of HIV
• HIV can only be spread by exchange of:
– Blood
– Semen
– Vaginal Secretions
– Breast Milk
Transmission cont.
• There are 4 main ways HIV can be transmitted
1. Through any form of sexual intercourse with an
infected person
2. Through shared needles or syringes that are
contaminated with blood of an infected person
3. Through contact with blood or blood products of
an infected person
4. From an infected mother to child, either during
pregnancy during birth or through breast feeding
Preventing HIV Infection
• THE ONLY NO-RISK BEHAVIOR WITH RESPECT
TO HIV AND AIDS IS ABSTINENCE
– Avoid having multiple sexual partners
– Avoid intravenous drug use
• Sexual Activity with drug users is also high risk
– Before 1985, people who had blood transfusions
were at risk
Can AIDS be Cured?
• Class Discussion….