Transcript Chapter 31 Immune System and Diseasesx

Honors Biology
Semester One
• What is an infectious disease?
• What is a noninfectious disease?
• Germ Theory
• Theorized by Louis Pasteur
• Proposed that specific microorganisms (pathogens/germs) cause diseases
• Hypothesized that if pathogens were eliminated from the body, the
person wouldn’t get sick
• Koch’s Postulates
• Pg. 941
• Bacteria
• Single-celled organisms
• Release chemicals that are toxic to the host or destroy healthy body cells
• Examples: Food Poisoning, strep throat, ear infections
• Viruses
• Disease-causing strands of DNA or RNA surrounded by protein coats
• So small that they couldn’t be seen until the electron microscope was invented
• Take over healthy cells, force it to stop normal activities, and produce more
viruses
• Examples: flu, cold, AIDS
• Fungi
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Can be multi or single-cellular
Pierce healthy cells and take the cell’s nutrients
Fungal infections normally occur in warm/damp places
Examples: Athlete’s foot
• Protozoa
• Single-celled organisms that prey on other cells
• Need healthy cells to complete their life cycles
• Example: Malaria
• Parasites
• Grow and feed on a host
• Some kill the host (why is this NOT the best idea?); some drain the body’s
resources without killing the host
• Examples: Heartworm, hookworms, pinworms
• With your table partner, make a list of ways pathogens might
enter the body:
• Now, read from the bottom half of pg. 943 through 944 and
list all the ways that pathogens can be transmitted:
• Think of your body as a castle during a battle in medieval
times…what might that entail?
• Immune system
• A body system that fights off infection and pathogens
• Several lines of defense
• Relies on physical barriers first; if those fail, immune system cells travel
through the lymphatic and circulatory system to the sight of infection
• First line of defense is the skin (castle’s outer wall)
• Physically blocks invading pathogens
• Secretes oil and sweat making the skin hypertonic (what does this mean?)
and acidic, an environment that many pathogens can’t survive
• However, the skin has openings like the eyes, nose, ears, mouth, and
excretory organs
• These organs are further protected by mucous membranes meant to
trap pathogens before they enter the body
• Sometimes, the first line of defense fails, and the immune system
gets to work!
White Blood Cells
• 6 different types
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Basophils
Mast cells
Neutrophils
Phagocytes
Macrophages
Lymphocytes (T cells and B cells)
Eosinophils
Refer to Fig. 31.6 on pg. 946
for function of each type of
WBC
Proteins
• Three types
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Complement Proteins
Antibodies
Interferons
Read pg. 947 to determine
functions of each protein type;
take notes!
• Occurs without the body undergoing an immune response
• Transferred between generations through DNA and between
mother & child
• Some diseases can pass between species; some can’t
• Genetic immunity is what a species has when they are immune to a
pathogen that can’t harm members of that species
• Inherited immunity is when pathogen-fighting antibodies in a mother’s
immune system are passed to the unborn baby through the umbilical cord
or through breast milk to infants
• Body-produced immunity in response to a specific pathogen
that has infected or is infecting the body
• Occurs after your immune system reacts to a pathogen invasion
and keeps you from becoming sick by a particular pathogen
more than once
• Body responds to pathogens and foreign particles with specific
and nonspecific responses
• Specific responses differ slightly for each pathogen; nonspecific responses
are the same for every pathogen
• Nonspecific Responses
• Inflammation is characterized by swelling, redness, pain, itching, and
increase warmth at the affected site
• Occurs when a pathogen enters the body or when body’s other tissues
become damaged
• Fevers develop when mast cells or macrophages release chemicals that
cause the hypothalamus (part of which system?) to increase the body’s
temperature
• Fever goes away when the chemicals are no longer being made by the
mast cells
• Low fevers stimulate the production of interferons, which prevent
viruses from reproducing
• Low fevers also make white blood cells mature faster, which is
important because only mature WBCs can destroy pathogens
• High fevers (103°F or above) are dangerous because at that
point, the hypothalamus can not longer regulate body
temperature, so enzymes that control chemical reactions in the
body stop functioning
• High fevers can cause seizures, brain damage, and in extreme
cases, death.
• When the immune system detects a pathogen, it triggers an
immune response
• Two types of specific immune responses:
• Cellular
• Humoral
• 4 total groups
• 2 groups will make a poster over cellular immunity
• 2 groups will make a poster over humoral immunity
• Everyone will make a Double Bubble Map comparing and contrasting
cellular and humoral immunity
• Occurs when the recipient’s immune system makes antibodies
against the protein markers on the donor’s tissue
• Why it’s important to find a “match” for organ/tissue donation
• Read on page 955 & 956, and list ways that pathogens are
controlled; be ready to discuss!
• Oversensitivity to a normally harmless antigen
• Allergens are antigens that cause an allergic reaction
• Steps of an allergic reaction:
• 1. Allergen enters body
• 2. Mast cells or basophils release histamine – a chemical that causes
nonspecific immune responses
• 3. Eosinophils sometimes also play a role in allergic reactions
• Scientists aren’t sure what causes some individuals to suffer from
allergies, while others do not.
• Leukemia
• HIV
• Both of these diseases weaken the immune system in different
ways…many times, individuals who have these types of
diseases die from complications of them, not the disease itself.
• Germs cause many diseases in humans.
• The immune system consists of organs, cells, and molecules that
fight infections.
• The immune system has many responses to pathogens and
foreign cells.
• Living in a clean environment and building immunity help keep a
person healthy.
• An overactive immune system can make the body very
unhealthy.
• When the immune system is weakened, the body can’t fight off
diseases.