Unit 10 Chapter 39 Immunity from Disease


Unit 10

Chapter 39

Immunity from Disease

The Nature of Disease

 Pathogens

 Disease producing agents, such as, bacteria, viruses, protozoans, fungi & other parasites

 Infectious disease

 Any disease caused by the presence of pathogens in the body

The Nature of Disease

Koch’s postulates of 1884

(a procedure to establish the cause of a disease)

1) A pathogen must be found in the body of a sick organism

2) The pathogen must be isolated & grown in the lab to produce a culture

3) When the cultured pathogen is placed in a new host, it should cause the same disease

4) The pathogen should be isolated from the new host and shown to be the original pathogen

The Nature of Disease

 Endemic disease

 Disease that are constantly present in a population (ex: common cold)

 Epidemic

 When many people in a given area are affected with the same disease at about the same time (ex: influenza)

The Nature of Disease

 Antibiotics

 Substances produced by microorganisms that, in small amounts, will kill or inhibit the growth

& reproduction of other microorganisms

 Ex: Penicillin, an antibiotic produced by a fungus, has been in use for over 50 years; many microorganisms are now resistant to penicillin

The Immune System

 Innate Immunity

Your body’s own built-in defense system

 First (& best) line of defense:

– Unbroken skin

– Body secretions, such as mucus, tears, sweat, & saliva

The Immune System

 Second line of defense is inflammatory response:

 Fever = increased body temperature slows or stops the growth of pathogens

 Phagocytes = white blood cells, such as macrophages , that destroy pathogens

 Interferon = proteins that protect cells from viruses

The Immune System

 Third line of defense is cellular immunity:

 Lymphocytes are types of white blood cells that defend the body against foreign substances

 T cells are lymphocytes that defend against abnormal cells & pathogens inside livings cells

 B cells are lymphocytes that provide immunity against antigens & pathogens in the body fluids

The Immune System

 Lymph

 Tissue fluid (to bathe, nourish cells) after it enters the lymph vessels that will return it to the blood

 Lymph nodes

 Glands that filter pathogens from the lymph before it returns to the bloodstream

The Immune System

 Acquired Immunity

 Defending against a specific pathogen by gradually building up a resistance to it.

 Passive = acquired naturally when antibodies are transferred from mother to unborn child through the placenta

 Active = acquired artificially when induced by vaccines

Nonspecific defense

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Cellular immunity

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