Chapter 40 Section 2 The Immune System

Agents of disease are called pathogens or antigens, Examples include: Fungi Protists Worms Cont.

Bacteria CUTS AND PUNCTURES OSE and

Viruses Swine Flu Virus Common Cold Virus HIV Virus

Pathogens enter the body through various body openings EYE NOSE MOUTH

and breaks in the skin

Disease can be transmitted to humans in various ways: Airborne droplets or dust particles Spoiled food Common inanimate objects

And vectors Like insects. For example:The parasite that causes malaria is transmitted by mosquitos. The mosquito is the vector.

And of course… Touching

Defenses against disease Nonspecific defenses prevent pathogens from entering the body Specific Defenses the immune response, the body’s response to the presence of a disease causing antigen

Nonspecific Defenses Your skin is your first and most important line of defense against disease Body secretions (mucus, oils, sweat, tears, and saliva) provide protection from pathogens as well.

Nonspecific Defenses cont. An Inflammatory Response is a response caused by injury to, or infection of the tissues. - Redness, swelling, pain, and heat(fever) are all part of the immune response to rid your body of harmful agents. - White blood cells (phagocytes) rush to the scene of the injury to prevent the spread of the pathogen.

Nonspecific Defenses cont. Pus is a collection of living and dead white blood cells, and pathogens. The pus will continue to form until the infection has ended. Once over, the pus will be cleared away by macrophages (a type of white blood cell).

Nonspecific Defenses cont. Fever – fever kills many pathogens and speeds up the action of white blood cells Interferon - proteins which help resist viral infection

Specific Defenses The immune response, is a series of specific defenses that attack antigens. Antibodies are specifically made to recognize the antigen and attack/destroy it.

Specific Defenses cont. 2 types of Immune Responses Cell Mediated – defense against abnormal cells and pathogens inside living cells Hummoral Immunity – defense against pathogen in body fluids

Function The function of the immune system is to fight infection through the production of cells that inactivate foreign substance or cells. Defenses: Nonspecific: skin, mucus, sweat, tears, Inflammatory response, Specific: Hummoral immunity and cell- mediated immunity, acquired immunity (Vaccines)

Organs of the Immune System

Homeostasis The body must defend itself from pathogens and foreign materials to maintain homeostasis. The immune system is the body’s main defense against pathogens. It recognizes, attacks, destroys and remembers each type that enters the body.

Immune System Disorders Allergies Allergies are an overreaction of the immune system. Allergens cause immune cells to release histamines which trigger mucus production (sneezing, watery eyes, runny nose etc.) and increased fluid/blood flow. Autoimmune disease When the immune system makes a mistake and attacks the body’s own cells, it produces an autoimmune disease.

Lymphatic system Chapter 37 Section 2

Lymphatic system function Collects fluid that is lost by the blood and returns it back to the circulatory system. As the fluid is transported, the lymph nodes filter/traps bacteria and other pathogens. Microorganisms are destroyed in the nodes. Old or damaged red blood cells are destroyed in the spleen. Lymph fluid then is ready to be returned to the circulatory system. Carries fat-soluble vitamins to the blood from the digestive system.

The lymphatic system organs Lymph vessels: lymph travels through to return to the circulatory system Lymph nodes: filters foreign particles out of the lymph Thymus: gland that helps white blood cells mature Spleen: destroys damaged red blood cells and platelets.

Homeostasis The lymphatic system helps maintain homeostasis in several ways. Returns lost fluid back to the circulatory system to avoid swelling Filters and cleans lymph fluid from foreign pathogens, damaged cells etc. Helps mature white blood cells which help fight infections.