The Immune System Basics

Pathogens of Disease Bacteria –Bacteria are cellular (prokaryotic) and are Living organisms - 3 common shapes Bacilli (rod), cocci (circular), spirilli (spiral) –Cause disease by Destroying cells and tissue Releasing toxins in body –Examples Strep Throat, tetanus, anthrax, syphilis, tuberculosis, MRSA, food poisoning, chlamidia, gonorhhea –Preventions Some have vaccines, personal hygiene, antiseptics –Treatments Antibiotics- substances that can be administered that kill the bacterial cells causing infection –Usually break down cell walls or interfere with metabolic processes

Pathogens of Disease Viruses –Noncellular particles Genetic material (DNA or RNA) Capsid-protective coating made of protein –Not considered living Cannot reproduce on own, no metabolic processes, no response to stimulus –Cause disease by Disrupting cellular activity and destroying cells –Examples Common Cold, Flu, Small Pox, HIV, chicken pox, genital warts, herpes, hepatitis –Prevention Some have vaccines, personal hygiene, antiseptics –Treatments None- body must defeat on own, some the body cannot defeat EVER Some drugs (antiviral) can slow the spread of virus within the body

Function of the Immune System to fight infections and protect the body from invaders. White Blood Cells-Specialized cells of the immune system fight disease

Pathogens Bacteria (food poisoning, tuberculosis, pneumonia) Viruses (influenza, AIDS, colds,ect..) Protists (malaria and others) Infect body and cause disease! Antigen- a substance on the surface of a pathogen that triggers an immune response (DEFENSE).

Nonspecific Defenses Skin- Creates barrier between external environment where pathogens exist and the inside of the body –Pathogens must enter body to cause infection/sickness Inflammatory Response (Swelling)-Blood vessels expand and WHITE BLOOD CELLS (disease fighters) enter the wound or infection site Fever- Body raises core temp. to try to kill pathogen –Some pathogens can only survive under certain temp.

Specific Defenses Humoral Response –Involve Special Types of White Blood Cells T-Helper Cells activate B-Cells when they detect invaders (pathogens) B- Cells (B lymphocytes) produce plasma cells Plasma cells produce antibodies –antibodies=substance that will cling to the antigen on the surface of a pathogen an immobilize the pathogen or cause them to cling together. –Once infection detected by helper T many plasma cells are generated B cells to produce antibodies Macrophages (PHAGOCYTES)-engulf and destroy immobilized or inactivated pathogens

Specific Defenses Cell Mediated –Helper T Cells- recognize pathogens and activate B cells (Humoral Response) and Cytotoxic (Killer) T Cells –Killer T Cells- Once activated kill pathogen directly

Immunity Bodies ability to not become sick against a specific invader/pathogen –It takes a while for plasma cells to figure out what antibody will kill a specific pathogen, many antibodies are produce in “trial and error method” –Pathogen causes infection and sickness in meantime –Eventually plasma cells produce an antibody that works. –Special B memory cells remember the correct antibody that worked against that specific invader –The next time the invader enters your body the Immune system knows how to destroy it before it can cause infection or disease.

Vaccine Altered (weakened) form of the real pathogen Scientists alter in lab –No longer capable of causing disease –Injected in body –Allows body to recognize and immune system build immunity to the pathogen When the real pathogen enters body your body is already immune (knows how to kill it before it can cause infection/sickness)

Treatments for Diseases Bacterial Diseases- bacteria are living things –Antibiotics-drugs that interfere with the chemical processes of living things Specifically harm bacterial cells without causing harm to us Viral Diseases-not living –Body must defeat on own, no cures

A.I.D.S and the Body AIDS infects and kills Helper T Cells Helper T Cells detect pathogens/invaders Once enough T Helper are killed by virus the body is no longer capable of recognizing invaders RESULT- Person becomes seriously infected or sick from pathogens that a healthy person may defeat rather easily –Usually die from simple infections (cold,flu,pneumonia)