Immunity Chapter 42

Objectives List the organs that are involved in the lymphatic system. Discuss the 3 functions of the lymphatic system Describe the three lines of defense. Describe how interferon and the complement help protect our bodies from disease Describe the 3 methods of infection by a pathogen Discuss the difference between passive and active immunity

LYMPHATIC SYSTEM The immune system is localized in several parts of the body –immune cells develop in the primary organs - bone marrow and thymus (yellow) –immune responses occur in the secondary organs (blue)

TYPES OF BLOOD CELLS lymphocyte

FUNCTIONS OF THE LYMPH Thymus – glandular organ near the heart – where T cells mature Bone marrow – blood-producing tissue located inside certain bones – blood stem cells give rise to all of the different types of blood cells Spleen – serves as a filter for the blood – removes old and damaged red blood cells – removes infectious agents and uses them to activate cells called lymphocytes

FUNCTIONS OF LYMPH CONT. Lymph nodes – small organs that filter out dead cells, antigens, and other “stuff” to present to lymphocytes Lymphatic vessels – collect fluid (lymph) that has “leaked” out from the blood into the tissues and returns it to circulation Lymphocytes - WBC that defend against foreign substances

Lymphatic system video clip

3 Main Functions of the Lymphatic System 1 - maintain homeostasis 2 - absorbs fats from digestive tract 3 - defend your body against disease

INFECTIOUS DISEASE Pathogen - disease causing microorganism (fungus,virus, bacteria, protozoans) Carrier: reservoirs of an infectious disease human (don’t always show symptoms) animals, soil, and water Types of Outbreaks: Endemic -constantly in population (cold) Epidemic - many people affected in a short time (flu)

TRANSMISSION OF PATHOGENS 1 - air - droplets of water, dust 2 - direct contact - touch, kiss, sexual 3 - contact object - food, water, drugs, toys, dishes, needles 4 - vector - insects, arthropods Ex: Mosquitos and Malaria, Lyme disease and Ticks, Plague and Rats/Fleas Incubation period = time it takes to show symptoms (very contagious)-pathogen is multiplying…

Reducing the Spread of Pathogens Wash hands Isolation

PASSIVE IMMUNITY The antibodies received through passive immunity last only several weeks. 1) Antibodies are received from mom through placenta to baby 2)Antibodies (Y) are also found in breast milk. 3)Injection of antibodies ( tetanus shot) 4)Taking a prescribed prescription (antibiotic)

ACTIVE IMMUNITY Innate ImmunityAcquired Immunity - invariant (generalized)variable (custom) - early, limited specificitylater, highly specific - the first line of defense“remembers” infection

ACTIVE IMMUNITY Result of exposure to antigen (pathogen) 1) Exposure to actual disease 2) Vaccines2) Vaccines (weak/dead pathogens)

1st LINE OF DEFENSE NONSPECIFIC MECHANSIMS Skin ( video clip) Mucus, saliva, tears Stomach acid

2ND LINE OF DEFENSE Phagocytes- formed in bone marrow. Engulf and devour pathogens whole Macrophage - large phagocyte (WBC) that engulfs and destroys pathogens -comes from the monocytes

Ecoli being attacked by macrophage (video clip)

Protecting a wound Damaged tissue - releases histamine Inflammation occurs - due to migration of phagocytes into injured area Chemical released that triggers the hypothatlamus to reset the body temperature - FEVER

SPECIFIC MECHANISMS OF DEFENSE ANTIGEN - Identifying protein found on all foreign entities ANTIBODIES ANTIBODIES - Protein shaped like a “Y” that aids in protecting us against pathogens

Types of Responses to Pathogens Primary Response -first time of exposure (natural or vaccine) -get sick and recover -Secondary Response -memory cells kick in to protect -no signs of sickness

3RD LINE OF DEFENSE SPECIFIC MECHANISMS Macrophage - engulfs pathogens and leaves an antigen exposed for identification

Allergic reactions/Transplant Rejection Allergy animation Organ transplant rejection QUIZ

Exercise and stress 1.Exercise: has been shown to boost the immune response moderate exercise increases the immune response in all age groups intensive exercise can stress the immune system 2. Sleep: lack of sleep and exhaustion decrease immune function 3. Emotional: psychological stress has also been found to decrease immune function

4. DIET a well-balanced diet is essential for good immune system health fats are very important in the production of WBCs, cytokines and natural killer cells selenium, zinc, and copper are required in small amounts, which you get if you eat a balanced diet vitamin E has been shown to boost antibody production in the elderly vitamin B 6 aids in antibody synthesis but mega-dosing can be harmful, too!

5. ENVIRONMENT Exposure to certain things in their environment may activate the immune systems of some people Chemicals –dioxin –pesticides –solvents Sunlight Medication Viruses Bacteria Food

6. Gender? Who gets more autoimmune diseases? women respond to antigens more strongly than men estrogen may affect the development or function of immune cells may explain why more women develop autoimmune diseases