ImmunologyThe study of the organs, tissues and

cells that create the body’s fight against disease.

Immunity – ability to stop a pathogen from establishing an infection, sometime before symptoms even occur.

Susceptibility – condition where a pathogen is able to successfully reproduce / replicate in a host.

The Immune System

– The Immune System is made up of:

– the cells in our bone marrow, thymus, – the spleen, the tonsils, the adenoids, skin, – the lymphatic system of vessels, ducts &

nodes,– blood and its contents

Look for these terms in the video:• Physical Barriers

Interleukin• Muscle Pain

Dendritic Cells• Fever

T-Cells• Cough

B-Cells• Natural Killer Cells

Antibodies• Macrophage

Memory Cells

The Immune System

Innate Immune System Acquired Adaptive Immune System(Learned Specific Immune System)

Response is non-specific Pathogen and antigen specific response

Exposure leads to immediate maximal response

Lag time between exposure and maximal response

Cell-mediated and humoral components

Cell-mediated and humoral components

No immunological memory Exposure leads to immunological memory

Found in nearly all forms of life Found only in jawed vertebrates

Physical Barriers

Natural Killer Cells

Macrophages

– “Big Eaters”, mature from Monocytes

– Patrol the interstitial areas for invaders

– Phagocytes, clean-up host debris

– Consume pathogens directly

– Non-specific – look for anything non-host

– Release interleukin

Specific Immunity

• Boost non-specific responses

• Identify specific invaders by their antigen

• Respond with a specific defense against the invading pathogen

• Memory of pathogens – “Adaptive”

• Use of a variety of Lymphocytes:– Humoral – B-Cells, antibodies in the blood– Cell-mediated immunity – T-Cells

•Humoral Response(of the “Humors”)

• B Cells – mature in the bone marrow

• Migrate to the lymphatic system

• Activated by antigen

• Release antibodies into the blood while remaining in the lymph system

• Antibodies cover and coat pathogens, rendering them useless and targeted for destruction.

Important Vocabulary

• Antigens - Anything causing an immune response, usually foreign material but may be our own tissues. (Antibody Generators)

• Antibody – molecules produced by the immune cells to identify the antigens of the invading pathogens

Lock & Key Relationship

Up to 100 Billion Specific Antigen Recognition Combinations

Cell-Mediated Response:• T-Cells are made in the bone marrow, migrate to

the thymus for maturation• T-Cells remain in the lymph system waiting to be

activated by an antigen.• After activation, T-cells clone themselves and move

to the site of infection.• Cytotoxic T-cells (CD8) directly kill infected cells• Helper T-cells (CD4) “train” macrophages &

stimulate B-cells to do their job better• Some T-cells form memory cells after the infection

is over.

Lymphatic System: A complex network of

lymphoid organs, lymph nodes, lymph

ducts, lymphatic tissues, lymph

capillaries and lymph vessels that produce and transport lymph fluid from tissues to

the circulatory system

Lymphatic System:The lymphatic system has three interrelated functions:

(1) removal of excess fluids from body tissues,

(2) absorption of fatty acids and subsequent transport of fat, as chyle, to the circulatory

system and, (3) production of immune cells

such as lymphocytes (antibody producing plasma

cells) and monocytes.

Immune Organs

– Tonsils

– Adenoids

– Thymus

– Lymph Nodes

– Spleen

– Peyer’s Patch

– Appendix

– Bone marrow

General Function:Infected cells & pathogens are

collected from the body and moved

through the lymphatic pathways to these

organs for destruction

Immune Organs

ImportantCellular Components