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Chapter 39.1 terms
1.
2.
3.
Pathogen
Infectious disease
Koch’s postulates
Chapter 39 RQ…
1.
2.
3.
4.
5.
What are disease-causing agents called?
What procedure is used to identify a
pathogen?
The common cold is an example of an
___demic disease.
What proteins protect cells from
viruses?
Which cells does HIV kill?
1. What is an infectious disease?
Caused by disease-causing agents –
“pathogens”
 Examples: bacteria, protozoans, fungi,
viruses, worms, etc.
 They are found in soil, water, animals,
and other people
 They disrupt your body’s homeostasis 

Anthrax, Malaria, Athlete’s
Foot, HIV, and tapeworm
2. What procedure is followed to
determine what causes a disease?

Lots of causes to diseases…
 Genetic,
wear & tear, exposure, malnutrition,
pathogens (which cause infectious disease)

Koch’s postulates help discover which
pathogen causes which infectious disease
Find same pathogen in every case of the disease
2. Isolate pathogen & grow outside of organism
3. Place pure pathogen in a healthy host, disease must
be caused
4. Re-isolate pathogen from the new host & show that
it is the same as the original 
1.
Good
Morning
3. What does it mean to be a
“reservoir” of a pathogen?
Anything that could harbor a disease
and potentially spread it
 The human body itself is the main
source of human diseases
 People who have the pathogen but are
not sick yet are in the “incubation
period” 

4. In what ways can infectious
diseases be transmitted?
1.
Direct contact
*common cold, influenza, STDs
2.
By an object
*bacteria, other microorganisms
3.
Through the air (coughing, sneezing)
*Streptococcus, measles
4.
A vector (intermediate organism)
*Malaria, West Nile, Lyme disease, the
bubonic plague 
Chapter 39.1 terms…
1.
2.
3.
Endemic disease
Epidemic
Antibiotic
5. How do viruses and bacteria
cause symptoms of a disease?

Viruses…
 Cause
damage by taking over a cell’s DNA
and organelles to make the cell make more
virus

Bacteria…
 Most
damage done by toxins that are
transported to the blood
 Can inhibit protein synthesis, destroy blood
cells and vessels, produce fever, or cause
convulsions by damaging the nervous system

6.Distinguish between the patterns
of endemic and epidemic diseases.


Endemic
Diseases that are
constantly present in
the population
Ex: the common cold


Epidemic
When many people in
the same area come
down with the
disease at the same
time
Ex: influenza,
typhoid fever, etc 
7. In what ways can infectious
diseases be treated?
Fight bacterial diseases with antibiotics
(NO effect on viruses… )
 Continued use of antibiotics has caused
bacterial resistance – penicillin example
 Streptococcus pneumoniae is now
penicillin-resistant (it causes pneumonia,
ear infections, and meningitis)
 There are anti-viral drugs, but our best
defense is our own immune system! 


Answer questions (1 – 4) on page 1030.
Chapter 39.2 terms
1.
2.
3.
Innate immunity
Phagocyte
Interferon
8. Distinguish between innate and
acquired immunity.
Innate – the body’s earliest lines of
defense and those you were born with
 Acquired – when your body builds up a
resistance to a specific pathogen 

9. How do your skin and body
secretions protect you?
Mucus – keeps various parts of the body
from drying out & traps foreign
substances
 Gastric juice – acidic & destroys
pathogens
 Sweat, tears, saliva – all have lysozyme
which breaks down bacterial cell walls 

10. How does inflammation help
fight pathogens?
Inflammation – redness, swelling, pain
and heat to the injured area
 It begins when damaged tissue cells and
basophils release histamine
 This causes the local blood vessels to
dilate, and fluid leaked into the area
helps destroy the toxic agents present


11. Distinguish among the white blood cell
types and describe their functions.



White blood cells –
Phagocytes – destroy pathogens by engulfing them. They
include…
- Monocytes which mature into macrophages, neutrophils, and
eosinophils
*macrophages (which are in body tissues) are the first defense,
which then consume all pathogens & damaged cells
- neutrophils (which circulate in the blood) come next
- new tiny monocytes squeeze into the area & mature into
phagocytes
The infected tissue, all of the dead pathogen, dead WBCs, and
body fluids is called PUS 
12. What are interferons? How are they
produced and what do they do?

Phagocytes alone cannot destroy viruses
 It

itself will get taken over 
Interferons: proteins that protect cells
from viruses
 They
are host-cell specific (can only
protect human cells)
 It is produced by a body cell that has been
infected – the message goes to noninfected cells, who then produce antiviral
proteins 
Chapter 39.2 terms…
1.
2.
3.
Lymph
Lymph node
Lymphocyte
13. How does the immune system recognize cells
that belong to you, and those that don’t?
Your cells have MHC markers that are
specific to you (nametags )
 Your immune system recognizes
substances that enter your body as
foreign by the protein markers
(antigens) on their surfaces 

14. What is the lymphatic
system’s job?
1.
2.
To help maintain homeostasis by
keeping a constant body fluid level
To help defend against disease 
15. Describe lymph/tissue fluid,
lymph nodes, and lymphocytes.

Tissue fluid – the stuff that surrounds all of your
cells
 Made
of water & dissolved substances from blood
 When it enters lymph capillaries it is now called
“lymph”
 This fluid returns to the bloodstream after if has been
filtered

Lymph nodes – small mass of tissue
 Contains

lymphocytes to filter pathogens from lymph
Lymphocytes – a type of WBC that defends
against foreign substances 
Continued..

Tonsils – large clusters of lymph tissue
 Form
a protective ring and provide protection
against pathogens

Spleen – stores lymphocytes, does not filter
lymph
 Destroys
bacteria and worn-out RBCs
 Acts as a blood reservoir

Thymus – located above the heart
 Stores

immature lymphocytes until they mature
16. What two immune responses
make up acquired immunity?



Antibody immunity
Helper T cells (made in bone
marrow & matured in the thymus)
activate…
B cells which become
either plasma cells…
that make antibodies AND
memory B cells that stay
in the bloodstream in case
the infection strikes again

Cell-mediated immunity
Cytotoxic T cells (stored in the
lymph nodes, spleen, and tonsils)


differentiate & clone,
then…
travel to the infection site
and…
Release enzymes directly
into the pathogens, who
then die 
17. Distinguish between T cells and B
cells. What do they each do?



T cells
A type of
lymphocyte
Produced in the bone
marrow and
processed in the
thymus
They activate B cells


B cells
Become plasma cells
or memory cells
when activated
Plasma cells make
antibodies (2000 per
second!)

Memory cells hang
around 
Chapter 39.2 terms…
1.
2.
3.
Acquired immunity
T cell
B cell
18. Describe how allergies and
autoimmune disorders might happen.
Allergies



When the immune
system overreacts to a
harmless substance
Mast cells release too
much histamine
This causes sneezing,
mucus production,
redness
Autoimmune disorders


When the immune system
attacks its own cells as
foreign
Ex: Lupus, rheumatoid
arthritis, multiple
sclerosis 
19. What is the difference between passive and
active immunity? How can you acquire these?
Passive
 Naturally acquired when
antibodies are
transferred from mom
to baby through the
placenta or milk
 Artificially acquired
when antibodies from
another person are
injected into someone
else (ex: snakebite)
Active
 Naturally when a person
is exposed to antigens &
produces antibodies
 Artificially when a
vaccine induces an
immune response (kind
of a “preview” for your
immune system) 
20. Overview the history of HIV and AIDS, and
describe how it impacts the immune system.

Human Immunodeficiency Virus 
kills helper T cells and leads to
Acquired Immune Deficiency Syndrome



Transmitted through blood or body fluids
HIV is a retrovirus. It attaches to the
receptor on a helper T cell, enters, and uses
reverse transcriptase to write it’s RNA into
DNA and become part of the host cell genome
For many years it continues to infect other
helper T cells, and usually progresses to
become AIDS 


Answer questions (1 – 4) on page 1041.
The End!