- The word immune literally means "protection.
- Protection from many hazards in the environment.
- Diseases cannot be immunized, such as cancer or AIDS.
- Immune system protects against foreign substances, and problems that may arise during that process.
- Cells of the immune system function to protect the individual organism against threats from anything that is foreign, or nonself. .
- Predominant threat to humans is infectious.
- invasion of the body by foreign organisms, viruses, bacteria, and fungi.
- Potential to cause disease.
- Disease results when cells tissues have been damaged so much that they can no longer function properly.
- Without an immune system humans would certainly die from infectious diseases.
- Immune system also provides long-term resistance, or immunity, to reinfection by organisms that have been precioulsy encountered.
- Once immune system has encountered a foreign material, it quickly and dfficiently responds to subsequnt exposures to the same material.
- Cell-medited immunity.
- Immune protection by antibody protein antibody-mediated immuntity.
- Phagocytosis destruction of foreign material they engulf and destroy a wide variety of molecules, particles and organisms, in contrast to antibodies, which are specific for only one antigen.
- Phagocytiosis is an important part of a protective process called inflammation.
- Tissue dammage such as cuts, splinters and infectious organisms.
- Other nonspecific mechanisms include physical and biochemical barriers.
- The skin and mucous cilia antibacterial enzymes found in saliva, sweat are biochemical barriers to many microorganisms.
- Basic characteristics of immunity were recognized more than 2000 years ago.
- Certain diseases could be acoided by inducing immunity with vaccines that induce specific immunity without causing disease.
- White blood cells known as lymphocytes travel individually in the blood circulation.
- Also collect in specialized lymphoid tissues and organs.
