Download Human Anatomy #1

Human Anatomy #2
Immune System
 Germ theory states that 
o A disease can be either 
 Infectious diseases 

Noninfectious diseases 
 Not caused by 
 They result from a person’s 
o Germ theory was proposed by 
o Led to 
 Robert Koch found that he could make healthy animals sick by 
o Disease causing agent (germ) is called a 
o From his experiments he concluded that four conditions must be met before it can
be said that a certain pathogen causes a disease – Koch’s Postulates:
 The pathogen thought to be the cause of the disease must be present in 

The pathogen must be isolated and grown outside the body in 
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Healthy animals injected with the pure culture must 
The pathogen must be re-isolated and cultured from the newly sick animal
and must be 
 There are different 
o Bacteria 
 Some bacteria cause illness by 
 Other bacteria release 
 Can be treated with antibiotics 
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Some fungal & parasitic infections are treated with a combination of
drugs including antibiotics
Antibiotics are NOT effective in treating 
o Viruses 

Cannot reproduce on their own. They must force host cells to 

Very 
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Best way to protect against viral infection lies in prevention by the use of
vaccines 
 When injected a vaccine stimulates 


Most provide protection only if 
Once the virus has been contracted 
o Fungi can be 
 Cause disease by 
 Usually occur in 
 Example 
o Protozoa are 
 Use host cells to 
 Take 
 Example 
o Parasites 
 Grow and feed on a 
 Some parasites 
 Example 
 Different pathogens cause 
 Pathogens can enter the body in 
o Pathogens can be transferred by 
o Indirect contact does not 
 Some can be transmitted by 
 Others can be transmitted by 
 Vectors 
o Direct contact requires 
 Includes:
 Kissing
 Sexual intercourse
 Hand shaking
 Many body systems protect you from 
o The immune system is the body system that 
o Many other tissues and systems help 
 The circulatory system 
 Nonspecific defenses 
o First Line of Defense against pathogens is nonspecific
o Includes:
 Skin is 

Mucous membranes 
 Second line of defense (if pathogens enter body):
o Inflammatory Response (nonspecific) 
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Inflammatory Response begins when mast cells or basophils 
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Histamines cause 
When this happens 

White blood cells 
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Fever 

Low fevers (~100°) 

High fevers (more than 103°) 
 Cells and proteins 
o White blood cells 
 Phagocytes 
 Lymphocytes:
 T cells 
 B cells 

6 types of white blood cells:
 Three types of proteins 
o Complement proteins:
 Some 
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
Some 
Some 
o Antibodies 
 Destroy pathogens in one of 3 ways:
 Make it ineffective by 
 Some 
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Others 
o Interferons 
 Interferons stimulate uninfected body cells to 

Other interferons stimulate the 
 Immunity 
o There are 2 types of immunity:
1) Passive immunity 
 Transferred between generations through 

Genetic immunity 
Inherited immunity occurs when pathogen fighting antibodies in a mother’s
immune system are passed to the unborn baby through the umbilical cord
or through the mother’s milk
2) Active Immunity 

 Specific Defenses 
o Specific immune responses begin with 

Antigens are 
 Each pathogen has a 
o When the immune system detects a pathogen 
 There are two specific immune responses 
 They both produce 
 Immunity is acquired when your body produces 
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Memory cells 
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When memory cells encounter the antigen a second time 
o Cellular immunity 
o Humoral immunity 
 Allergies occur when the immune system responds to 
o When someone has an allergy, the immune system produces antibodies in
response to an 
 Allergens are 
 Allergens cause 
o There are different allergens:
 Foods 
 Airborne 
 Chemical 
o Allergens can cause 
 Anaphylaxis is 
 Immune system releases large quantities of 
 Causes blood vessels to become too 
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Causes airways to tighten so 
If not treated immediately, anaphylaxis can cause 
 Autoimmune diseases occur when 
o Autoimmune diseases are 
 White blood cells cannot tell the difference between 

White blood cells treat the body cells like they are 
 Tissues 
o There are over 
o Common autoimmune diseases:
 When the immune system is weakened the body cannot 
o Leukemia is 
 Does not form 
 It prevents 
 Characterized by immature white blood cells that 


Causes a 
Leukemia leads to 
 Opportunistic infections 
 HIV targets the 
o The human immunodeficiency virus (HIV) is a 
o Retrovirus is a type of virus that contains 
o Attacks and weakens the 
o Is transmitted by 
 Can only live in human blood cells and will not 

HIV is transmitted through:
 Sexual intercourse with an infected individual
 From infected mothers to their unborn children
 Using a needle from an infected individual 

HIV reproduces in 
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Step 1: When HIV first enters the body, T cells activate B cells and the
activated B cells make 
Step 2: Because HIV kills T cells and reproduces more quickly than T cells,
as HIV continues to reproduce 

Step 3:With fewer T cells, B cells cannot be activated to make antibodies.
HIV and pathogens that cause opportunistic diseases 
o HIV infection leads to 
 Acquired Immune Deficiency Syndrome (AIDS) 

A person with AIDs can have 

AIDS always results in 