{Chapter 47

The Immune system

What is a pathogen? Any agent that causes

disease Koch was the first to

establish how to identify individual pathogens

Identifying pathogens

All of these are caused by communicable diseasesan infectious disease transmissible by direct contact

with an affected individual or the individual's discharges or by indirect means

Pathogens must enter the body to cause disease

SNOT!!-Internal structures Yes, your mucus is the first line of

defense Mucus membranes secrete mucus

Your skin!! releases oil, sweat, waxes that are toxic

to pathogens

The first line of defenseNonspecific immune response

Inflammatory response Activated when any pathogen gets past the first line

of defense

The second line of defense

The body temperature may rise when the body fights off a pathogen.

Obviously called a fever Fevers can slow bacterial and viral growth A fever too high can actually damage proteins

needed to fight infection.

Temperature response

Yes, there are proteins coded for nonspecific defenses.

There are 20 proteins that make up your complementary system

Some of these proteins attack, stab, and destroy pathogen cells

Interferon-a protein released by cells infected with viruses.

Causes nearby cells to make a protein that helps them resist viral infection

Proteins for defense?

The immune system is the cells and tissues that recognize and attack foreign substances in the body and provides the body’s specific defenses.

The Immune SystemSpecific immune response

The immune system fights pathogens, stops the growth and spread of cancers

Made up of several tissues and white blood cells

White blood cells are called lymphocytes Each white blood cell is made in your bone

marrow Each day billions are made

The thymus, located above the heart, is where your T cells mature

The Lymph nodes-collect pathogens and expose them to the lymphocytes

The Immune SystemSpecific immune response

The Immune SystemSpecific immune response

Your lymphocytes can actually recognize foreign invaders

Think about a flu shot Antigens- any substance that the immune system can

recognize and react with Any time your body reacts against an antigen, this is

called an immune response

Recognizing Pathogens

Antigens are located on the surface of a pathogen Lymphocytes have unique receptor proteins on their surface Receptor proteins recognize antigens of the same shape and

bind, rendering the antigen useless. Bacteria can be covered by many different types of antigens,

causing lymphocytes to react.

Recognizing Pathogens

In a nut shell Your body is invaded by pathogens Your macrophage engulf the pathogen and express the

antigen Helper cells bind to the antigen site. This binding causes you to create memory cells and plasma

cells Memory cells “remember” the antigen Plasma cells carry antibodies

Antibodies are highly specialized cells that make defensive proteins

Are in the shape of a Y

The Immune response

Immunity The ability to resist an infectious disease

Vaccination The introduction of antigens into the

body to create immunity

Immunity and vaccination

This is a solution that contains a dead or a weakened pathogen or material from a pathogen

The antigens are still present, therefore your body responds and creates the memory cells.

This response can provide a secondary immune response if affection occurs again.

Common diseases that have been controlled through vaccines

Polio, measles, mumps, tetanus, and diphtheria These vaccines can wear off

Your doctor may recommend a “booster” What are the issues with vaccines?

Vaccines

Fight bacterial infections Do antibiotics help fight virus?

Think of how many times you have a cold or the flu and a Dr. prescribes antibiotics!

When used properly, they can save lives. Remember evolution

Pathogens evolve and cause a very serious issue Antibiotic resistance!!

occurs when bacteria change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply causing more harm.

Antibiotics

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