Disease and Immunity Notes

Disease and Immunity Notes

Homeostasis in an organism is constantly threatened. Failure to respond effectively can result in disease or death.

Viruses, bacteria, fungi, and other parasites may infect plants and animals and interfere with normal life functions.

Immune response--defensive reaction of the body to foreign substances or organisms

The immune system also protects against some cancer cells which may arise in the body.

Natural Killer Cells destroy the bodies own infected cells, especially those containing viruses. They may attack cells that might form tumors.

antigens--foreign substances or organisms which stimulate the body to make antibodies

antibodies--specific plasma proteins which render harmless or destroy a specific antigen produced by certain white blood cells (ex. lymphocytes)

immunity--the accumulation of specific antibodies in the plasma of the blood enabling the individual to resist specific diseases

Ways of acquiring immunity:

1. Active immunity--the individual either possesses or forms his or her own antibodies within his or her own body

** The antigen-antibody reaction occurs within the body in response to either contact with the disease-causing organisms or their products, or by receiving a vaccination.

Vaccinations use weakened microbes or parts of microbes to stimulate the immune system to react. (primary immune response) This reaction stimulates the body to fight subsequent invasions by the same microbes. (secondary immune response)

2. Passive immunity--a temporary form of immunity produced by the introduction of antibodies into an individual from another organism "Let the others do the work" This immunity is of short duration.

allergy--an extreme body reaction to certain foreign proteins (antigen-antibody rx.)

Some allergic reactions are caused by the body's immune responses to usually harmless environmental substances.

autoimmune diseases -- the immune system attacks some of the body's own cells

exs. Crohn's disease, myasthenia gravis, multiple sclerosis, lupus, fibromyalgia

Antibodies formed in response to these substances may cause inflammations and/or result in the release of a chemical substance called histamine. The histamine causes the allergic response.

antihistamine--stops this allergic reaction

AIDS (Acquired immune deficiency syndrome)

-- a viral disease which damages the immune system

-- this damage leaves the body unable to cope with numerous infectious agents and cancerous cells

Our increased knowledge of immunity has resulted in the ability to type blood and transplant organs.

Major lymph vessels have lymph nodes which contain phagocytic white blood cells which filter bacteria and dead cells from the lymph.

[Some other causes of disease include]

1. inheritance

2. toxic substances

3. poor nutrition

4. organ malfunction

5. poor personal behaviors and choices

cancer -- results from gene mutations in cells which cause uncontrolled cell division

** Exposure of cells to certain chemicals and radiation increases mutations and thus increases the chances of cancer.

Biological research (such as the human genome project) generates knowledge used to design ways of diagnosing, preventing, treating, controlling, and curing diseases of plants and animals.