Unit 8- THE IMMUNE SYSTEM - PowerPoint Presentation

Slide1

Unit 8-THE IMMUNE SYSTEM

Slide2

ImmunityImmunityThe ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells.Immune SystemThe system in the body responsible for maintaining homeostasis by recognizing harmful from nonharmful

organisms.

Slide3

Foreign InvadersCalled PathogensViruses, bacteria or parasite that causes disease/immune response.Toxins that pathogens produce may cause harm

as well.

Slide4

Parts of the Immune SystemBlood - White Blood Cells in particularLymph nodesThymus Gland – Produces T

CellsBone Marrow –

Produces B Cells

Slide5

The Body’s THREE lines of DefenseFirst Line of Defense – The SkinProvides Physical and Chemical barriersPhysical – hard to penetrate, made of indigestible keratin

Chemical – tears, sweat

Slide6

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 macrophagesNatural Killer Cells

Inflammation - caused by release of histamine.

Fever – caused by histamines. The fever (high temp) kills

invaders.

Slide7

Third Line of Defense This is a specific response to a specific pathogen.The response involves the creation of antibodies and killer cells.

Slide8

White Blood CellsB-cells mature in bone marrow then concentrate in lymph nodes and spleen-Produce antibodiesT-cells mature in thymusB and T cells mature then circulate in the blood and lymphCirculation ensures they come

into contact with pathogens

Slide9

B CellsActivated B cells produce lots of antibodies, about a

1000/sec. The antibodies travel to the blood, lymph, lining of gut and lungs.

Antibodies stay in the blood longer but eventually their numbers go down.

Slide10

B -LymphocytesSome activated B cells become memory cells.Memory cells divide rapidly as soon as the pathogen is reintroduced.

When the pathogen/infection infects again it is destroyed before any symptoms show.

Slide11

T-CellsTwo types: Helper T cells -

help the immune response start

Killer T cells -

Kill body cells making new pathogen

Memory T cells

-

r

emain in body

Slide12

The Immune Response ExplainedPathogens infect cells.Macrophage ingests pathogen and displays portion on its surface.

Helper T- Cell recognizes pathogen on the surface of the macrophage and becomes active.

Helper T-Cell activates Killer T-Cells

and B-Cells.

Slide13

The Immune Response Explained5. Killer T-Cells kill infected cells.6. At the same time, B-Cells start making antibodies which kill already made pathogens.

7. Memory T and Memory B cells remain in the body to speed up the response if the same antigen reappears

.

Slide14

Active and Passive ImmunityActive immunityLymphocytes are activated by antigens on the surface of pathogensNatural active immunity - acquired due to infectionArtificial active immunity –

vaccinationTakes time for enough B and T cells to be produced to mount an effective response.

Slide15

Active and Passive ImmunityNatural passive immunityA mother’s antibodies pass across the placenta to the fetus and remain for several months.Colostrum (the first breast milk) contains lots of antibodies which

help the baby fight infection

Slide16

VaccinesA preparation containing anti-pathogenmaterial:Whole live microorganismDead microorganism

Slide17

VaccinesWhy aren’t they always effective?Natural infections persist within the body for a long time so the immune system has time to develop an effective response, vaccinations from dead pathogens do not do this.

Less effective vaccines need booster injections to stimulate secondary responses

Slide18

AllergiesWhen the immune system responds to harmless substancesAllergens – substances which do no real harmAllergens include house dust, animal skin, pollen, house dust

mites and their feces

Slide19

Autoimmune Diseases A. Autoimmune Diseases - Occur when the immune system no longer recognizes the cells of your own body… the immune system attacks healthy body cells. Examples include:Diabetes Mellitus

Lupus Multiple Sclerosis (MS)

Rheumatoid ArthritisAutoimmune diseases are more frequent in women than in men due to hormonal differencesThese diseases are treated with drugs that suppress the immune system as well as with antibodies that attack lymphocytes

Slide20

Autoimmune DiseasesDiabetes Mellitus (Type I or Juvenile Onset) -The immune system destroys the Insulin producing cells of the pancreas.Multiple Sclerosis

-occurs when the body attacks its own neurons.

-effects include the loss of motor control, feeling or even paralysis of the affected areas.

-MS generally attacks the neurons of the optic nerves, the brain and the spinal cord.

Slide21

Autoimmune DiseasesRheumatoid ArthritisThe body’s own antibodies attack and destroy tissue at the jointsThe condition is chronic, with episodes of pain and swellingNo cure

, but patients may have joints removed and replaced by artificial ones

Slide22

Immune System Diseases B. Immune Deficiencies - The inability of the immune system to protect the body from pathogens.Severe Combined Immune Deficiency (SCID)HIV/AIDS

Slide23

Immune System DiseasesHIV/AIDS (Human Immunodeficiency Virus) Attacks and kills Helper T Cells. Without these cells, circulating antibodies drop in number and the body is left more vulnerable to other invading pathogens.

Slide24

Organ TransplantsOrgan Transplants and RejectionIf the body receives tissue from another person or animal the body will recognize this tissue as foreignAn immune response will be started against the new tissueIf the immune system isn’t repressed, the new tissue will be rejectedThis is why organ donors are closely matched to their recipients