Transcript Biology
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)