Understanding DiseasesUnderstanding Diseases

Chapter 8 Lesson 1Chapter 8 Lesson 1

Understanding DiseasesUnderstanding Diseases

A communicable Disease is an illness A communicable Disease is an illness caused by pathogens that can be passed caused by pathogens that can be passed from one person to another person, animal from one person to another person, animal or object.or object.

A germ is something that causes disease.A germ is something that causes disease. A more official term for germ is PATHOGEN! A more official term for germ is PATHOGEN!

They are disease causing agents which could be They are disease causing agents which could be single or multi-cellular. single or multi-cellular.

Causes and Spread of DiseaseCauses and Spread of Disease

Pathogens come in all different shapes Pathogens come in all different shapes and sizes:and sizes: Such as: bacteria, protozoa, fungi, rickettsia, Such as: bacteria, protozoa, fungi, rickettsia,

and viruses.and viruses.

Not all Bacteria and Fungi are pathogens!Not all Bacteria and Fungi are pathogens!Some bacteria are beneficial and used in the Some bacteria are beneficial and used in the digestion process.digestion process.

Some Fungi are used as food (mushrooms)!Some Fungi are used as food (mushrooms)!

Type of Type of PathogenPathogen

DescriptionDescription DiseasesDiseases

BacteriaBacteria Single celled organism that live Single celled organism that live nearly everywhere! They rapidly nearly everywhere! They rapidly reproduce!reproduce!

Strep throat, lyme Strep throat, lyme disease, urinary tract disease, urinary tract infectionsinfections

VirusesViruses Smallest and simplest pathogens. Smallest and simplest pathogens. They reproduce inside healthy cells. They reproduce inside healthy cells.

Colds, chicken pox, Colds, chicken pox, small pox, measles, small pox, measles, herpesherpes

ProtozoaProtozoa Single celled organisms that capture Single celled organisms that capture other life forms for food. Live within other life forms for food. Live within the body as parasites.the body as parasites.

Malaria, dysenteryMalaria, dysentery

FungiFungi Single celled or multi cellular Single celled or multi cellular organisms that feed on organic organisms that feed on organic material. Yeasts and molds cause material. Yeasts and molds cause diseases. diseases.

Athletes foot, ring worm, Athletes foot, ring worm, nail fungal infections. nail fungal infections.

RickettsiaRickettsia Pathogens similar to bacteria but Pathogens similar to bacteria but multiply like viruses.multiply like viruses.

Typhus, Rocky Mountain Typhus, Rocky Mountain Spotted fever. Spotted fever.

How are Pathogen’s Spread?How are Pathogen’s Spread?

Direct ContactDirect Contact Kissing, touching, sharing glasses or utensils, Kissing, touching, sharing glasses or utensils,

sexual activity, needle sharing. sexual activity, needle sharing.

Animal bites or scratchesAnimal bites or scratchesIndirect contactIndirect contact Doorknobs, table tops, faucet handlesDoorknobs, table tops, faucet handles

Insect Stings or bitesInsect Stings or bitesContaminated food or water Contaminated food or water Food borne illnesses, etc Food borne illnesses, etc

The Immune SystemThe Immune System

Made of cells, tissues, and organs that fight off Made of cells, tissues, and organs that fight off pathogens. pathogens.

First line of defense:First line of defense: SkinSkin Mucous MembranesMucous Membranes TearsTears SalivaSaliva SweatSweat Stomach AcidStomach Acid

The Immune SystemThe Immune System

Second Line of DefenseSecond Line of Defense A general reaction to invaders that is known A general reaction to invaders that is known

as the non specific immune response.as the non specific immune response.

Phagocytes play a role in this defense.Phagocytes play a role in this defense. White blood cells that find, engulf and digest pathogens. White blood cells that find, engulf and digest pathogens.

Phagocytes release chemicals that cause Phagocytes release chemicals that cause inflammation at the site of an infectioninflammation at the site of an infection

It causes the area to become red, swollen and warm.It causes the area to become red, swollen and warm. If the infection spreads through the whole body, the If the infection spreads through the whole body, the

phagocytes cause a fever. phagocytes cause a fever.

The Immune System’s Specific The Immune System’s Specific ResponseResponse

This is the body’s This is the body’s third line of defensethird line of defense

Lymph plays an Lymph plays an important partimportant part It bathes cells and It bathes cells and

cleans them of foreign cleans them of foreign organisms. organisms.

Lymph nodes filter the Lymph nodes filter the lymph. lymph.

Lymph contains Lymph contains lymphocyteslymphocytes B-CellsB-Cells T-CellsT-Cells Killer CellsKiller Cells

Both recognize antigens

The Immune System’s Specific The Immune System’s Specific ResponseResponse

AntigensAntigens- substances that cause an immune reaction in - substances that cause an immune reaction in the body. the body.

Once B-Cells find antigens, they begin making Once B-Cells find antigens, they begin making antibodies. antibodies.

Antibody- a protein in the blood that destroys a specific antigen. Antibody- a protein in the blood that destroys a specific antigen.

Memory cells remember the specific antigen and they Memory cells remember the specific antigen and they speed the production of more antibodies. speed the production of more antibodies.

T-cells and Killer Cells destroy the antigens as well. T-cells and Killer Cells destroy the antigens as well.

Specific Parts of the Immune Specific Parts of the Immune SystemSystem

Lymph NodesLymph Nodes Lymph carries captured antigens to lymph nodes Lymph carries captured antigens to lymph nodes

where it is filtered out. where it is filtered out.

ThymusThymus Small gland on the upper chest that produces T-CellsSmall gland on the upper chest that produces T-Cells

SpleenSpleen Filters dangerous substances from the blood. Carries Filters dangerous substances from the blood. Carries

antigens to the spleen which prompts B-Cells to antigens to the spleen which prompts B-Cells to produce antibodies. produce antibodies.

Bone MarrowBone Marrow Bone Marrow produces lymphocytesBone Marrow produces lymphocytes

Caring for your Immune SystemCaring for your Immune System

Get regular physical examinationsGet regular physical examinationsVisit a physician when you feel ill.Visit a physician when you feel ill.Follow directions on your medication. Follow directions on your medication. Reduce StressReduce StressExercise Regularly.Exercise Regularly.Get 8 hours of sleep each nightGet 8 hours of sleep each nightPlan healthy mealsPlan healthy mealsAvoid drugs and alcohol. Avoid drugs and alcohol.