Disease and the

Immune System

Overview of Lesson

• Immune system

• Viral infections

• Bacterial infections

• E. coli outbreaks

A disease is any change, other than an injury, that disrupts the normal functioning of the body. It is the inability to maintain homeostasis.

Influenza VirusFlu

Streptococcus Pneumoniae Bacteria•Ear infections•Meningitis•Pneumonia

Causes

1. Inheritance: sickle-cell anemia, hemophilia

2. Toxic Substances: cigarette smoke, alcohol

3. Poor Nutrition: ricketts, anorexia, scurvy4. Organ Malfunction: heart disease, diabetes5. Personal Behavior: drug addiction,

alcoholism

Causes continued

6. Pathogens: organisms that enter the body and cause infectious diseases

• Antigens– Toxins that pathogens produce that cause

harm to an organism.– Are pathogens abiotic or biotic?

Pathogens

• Examples of diseases caused by viruses:mono, flu, common cold, chicken pox, small pox, pertussis, AIDS

AIDSsmall pox

chicken pox

Pathogens

6. Pathogens continued:b) Bacteria: Tuberculosis, E. coli, cholera,

tetanus

tuberculosisE. coli cholera

tetanus

Pathogens

c) Fungi: ringworm, athlete’s foot, jock itch

ringworm athlete’s foot

Pathogens

d) Parasites: lice, malaria, dysentery, tapeworm,

lice

malaria in red blood cells

Amoebic dysentery

tapeworm

Immunity• Immunity

– ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells.

• Immune System– body system thatmaintains homeostasis by distinguishing harmful from nonharmful Organisms that enter the body and responding

Parts of the Immune System

1. Blood - White Blood Cells in particular.2. Lymph nodes3. Thymus Gland – Produces T Lymphocytes4. Bone Marrow – Produces B Lymphocytes

Lymphatic system  

• A network of glands and vessels that drain interstitial fluid from body tissues and return it to the circulatory system.

• Fluid is “scanned” for foreign cells

Lymph Organs

• bone marrow

• lymph nodes

• spleen

• thymus

Function of 2 Main Groups of Cells1. Leukocytes—Non-specific defense. Rely on

Phagocytosis to ingest invading microbes. They include Macrophages and White Blood Cells.

2. Lymphocytes—Provide high specificity and diversity to the immune system. Allow for extremely aggressive response microbial attack. They include B-Cells and T-Cells

How does the body fight infection/foreign invaders?

The Body’s THREE lines of Defense

First Line of Defense – The Skin• Provides Physical and Chemical barriers

• Physical – hard to penetrate, made of indigestible keratin

• Chemical – tears, sweat

Second Line of Defense – Nonspecific Immune Response

These are defenses the body uses no matter what the invader may be. These defenses include:– Phagocytosis – done by Macrophages

– Natural Cell Killers

– Inflammation - caused by release of Histamine from leukocytes

– Fever – caused by histamines. The fever (high temp) kills invaders by denaturing their proteins.

Macrophage: A phagocytic cell found in the liver, spleen, brain and lungs. Travels to all areas of the body to find and eat pathogens.

This is a specific response to a specific pathogen/antigen.

• The response involves the creation of Antibodies.

Third Line of Defense – Specific Immune Response

Antibodies

• Y-shaped protein molecule.• Made up of variable and

constant regions.• Made up of Heavy and

Light chains.• Produced by B-

Lymphocytes• Function: Recognize

antigens, bind to and deactivate them.– Note: Variable region

recognizes the antigens.

How An Antibody Operates/Works?

Deactivation of a bacterium by an antibody.