Anatomy 1. Integumentary System 2. Skeletal System 3. Muscular System 4. Nervous System 5. Circulatory System 6. Respiratory System 7.Digestive System 9. Endocrine System 8. Excretory System 11. Immune system 10. Reproductive System 11 Major Systems

Today you will: Compare & contrast non-specific & specific immunities Describe the structure & function of the lymphatic system Understand the importance of B & T cells Differentiate between passive and active immunities

What’s the purpose of receiving a vaccine? Why do you think schools require that students be up to date on their immunizations? Aside from vaccines, how might you build immunity to a specific infectious disease?

Pathogen: a disease causing agent Most pathogens are infectious microbes such as bacteria or viruses that are capable of causing disease. Other parasitic organisms such as fungi and some protozoans are also considered pathogens. NOT ALL microbes are harmful, the word pathogen refers specifically only to microbes that cause disease.

The body has a number of defenses in the immune system that fight off pathogens Some defenses are considered non-specific because they are not aimed at a specific pathogen Help to prevent a disease If disease does occur, this helps to slow the spread of the disease.

Dead skin cells help protect against invasion by microorganisms. Some bacteria live on our skin symbiotically. They digest oils produced by the skin and then secrete a mild acid that inhibits many pathogens.

Saliva, tears, and mucus contain lysozyme. Lysozyme: an enzyme that breaks down bacterial cell walls killing the bacteria. Mucus acts as a protective barrier by blocking bacteria from sticking to the epithelial cells (cells under the mucus lining).

If a pathogen gets through the non-specific barriers there are 3 non-specific responses that may occur.

Phagocytosis: Process in which a phagocytic cell surrounds and internalizes a foreign microorganism. Once the pathogen is internalized the phagocyte releases digestive enzymes and other chemicals from their lysozomes to destroy the pathogen. bacteriumphagocyte

Virus infected cells secrete a protein called interferon. Interferon binds to neighboring cells and causes those cells to produce antiviral proteins so those cells aren’t infected with the virus. Interferon can also allow cells to communicate to the immune system to eradicate a pathogen or a tumor.

Increase blood flow to the infected area makes blood vessels more permeable to allow white blood cells to enter the infected are.

Lymphatic system Organs and cells that filter lymph fluid and destroy pathogens.

Lymphocytes: a type of white blood cell (WBC) produced in the bone marrow Lymph nodes Tonsils Spleen Thymus glans Other tissues in mucous membranes in the intestinal, respiratory, urinary, and genital tracts.

B-Cells Helper T-Cells Killer T-Cells Memory Cells

Antigen: A substance on a pathogen that causes the immune system to produce antibodies. Antigens have marker molecules (proteins) on their surface that have unique shapes making them identifiable to other cells. Antibody: A substance produced by the immune system in response to (against) an antigen

Located in all lymphatic tissues and produce antibodies An activated helper T-Cell presents processed antigens (from a pathogen) to a B-Cell. B-Cell: manufactures antibodies to bind the antigen in the body. The antibodies enhance immune system response by binding to pathogens making them more susceptible to phagocytic destruction and also speed up inflammation and non-specific response.

Antibody Receptor Antigen Markers

Helper T-Cells bind to & activate cytotoxic T-Cells (Killer T- Cells) to help fight a pathogen Activated Killer T-Cells destroy pathogens and release chemicals called cytokines. Cytokines help to stimulate the immune system. Especially good at killing virus infected cells Pathogen Killer T-Cell

Temporary protection produced when antibodies made by other people or animals are transferred into the body

Long term immunity that occurs after the immune system has been exposed to disease and memory cells have been produced.

This occurs when the immune system is re-exposed to a particular antigen. Faster response compared to the primary exposure B and T-Cell response is greater during a secondary exposure The memory of the antigen lasts longer (more memory cells produced) Memory Cells: Remember antigens of pathogens we have been exposed to in the past so our body can quiskly destroy the pathogen if it enters the body again.