The Immune System

Basic Vocab. Disease ___________- any change that disrupts the normal functions of the body. __________- Disease-causing agents; such as; viruses, bacteria, protists, worms, fungi ______________-diseases caused by pathogens _________– triggers immune response (bad guys) _______– protein; destroys pathogens (good guys) Pathogen Infectious Diseases Antigen Antibody

How Diseases are Spread Physical Contact _______________– transmitted when a healthy person touches a person with a disease. _______________- transmitted through bodily fluids _____________- through the air or by touching objects that have been infected and than touching your nose or mouth. Sexual Contact Indirect contact

How Diseases are Spread Some behaviors can help to control transmission of diseases. Such as covering your mouth with a tissue when you cough, & wash your hands

How Diseases are Spread Contaminated Food and Water __________________________– caused by eating food containing pathogens or drinking un-sanitized water. ________________- Vectors carry diseases like Lyme disease, West Nile virus, & rabies Infected Animals

Immune System The Immune system is the body’s primary defense against pathogens. 4 Nonspecific Defenses: Not directed against any one pathogen, guards against all infections. Skin Mouth & Respiratory Passages Inflammation Fever

Skin Most important nonspecific defense Few pathogens can penetrate that tough layer of __________ protein (dead skin) at the skins outer surface keratin

2. Mouth & Respiratory Passages Millions of microorganisms enter each day Passages leading to lungs are coated with________ Mucus traps airborne pathogens Swept into the ___________ to be destroyed mucus digestive system

3. Inflammation Occurs when _________ do enter the body (usually through skin) Blood vessels near wound expand WBC leak from the vessels to invade the infected tissues ____________(wbc) engulf and destroy them Infected tissue may become swollen and painful pathogens Phagocytes

White blood cell chasing bacteria When a wound breaks human skin, it creates a gateway for harmful pathogens to invade human cells. Neutrophils, which are a type of white blood cell, live in human blood vessels. When pathogens invade a human cell, neutrophils travel to the infection site to destroy the invading pathogen. The first step in this process is engulfing the pathogen. Once the neutrophil has completely surrounded the pathogen, it produces an oxidant, hypochlorous acid. Hypochlorous acid is a biocide, meaning it kills organic material. Once produced by the neutrophil, it kills the bacteria almost instantly.

4. Fever ____________ has spread Pathogen ____________ has spread Immune System releases chemicals that increase the _______________ Pathogens can only survive within a narrow temperature range body’s temp

Specific Defenses Attacks the particular disease causing agents 2 types Antibody & T cells

Antibody Immunity Antigens stimulate production of ______________. Antibody has two binding sites which are specific in a particular antigen antibodies

An antibody matches an antigen much as a key matches a lock An antibody matches an antigen much as a key matches a lock. Whenever antigen and antibody interlock, the ___________ marks the antigen for _____________ antibody destruction

Lymphocytes White blood cells One group called B cells Another group called T cells

B cells Mature in ______________ Produce antibodies bone marrow Mature in ______________ Produce antibodies as B cells develop, antibody genes in each rearrange themselves in different ways. When complete, immune system contains millions of B cells each capable of producing a slightly different antibody. __________shot of weakened or killed pathogens to stimulate production of antibodies. Vaccine-

T-Cells Three types: ____________- track down and ________ pathogens & foreign tissue ___________- ________ pathogen & send message to Killer T _____________– turns ____ the immune response Killer T destroy Helper T identify Suppressor T off

HIV/AIDS __________- infects, weakens, and gradually destroys the helper T cells. ____________- cells are responsible for the rejection of tissue transplants Killer T

Immune Disorders Allergies- overreaction of the immune system to an antigen in the environment Autoimmune Diseases- immune system makes mistakes and attacks its own cells Multiple sclerosis- attacks the myelin sheath that surrounds nerve fibers Rheumatoid Arthritis- antibodies attack connective tissues around the joints Type 1 Diabetes- antibodies attack the insulin producing cells of the pancreas