1. The Lymphatic System

2. Functions of Lymphatic System
Drain fluid back into the bloodstream from tissues
Filters lymph
Filters the blood
Fights infections
As the blood circulates, fluid leaks out into the body tissues. This fluid is important because it carries food to the cells and waste products back to the bloodstream. The leaked fluid drains into the lymph vessels. It is carried through the lymph vessels to the base of the neck where it is emptied back into the bloodstream. This circulation of fluid through the body is going on all the time.

3. The Lymphatic System
Lymph- clear fluid that circulates around the body tissues
Contains high number of white blood cells
Includes- lymph nodes, spleen, thymus, tonsils, and adenoids

4. Lymph Nodes Located in armpits, groin, neck, abdomen, pelvis and chest
Filter the lymph as it passes through
White blood cells attack any bacteria or viruses
If cancer cells break away from a tumour, they often become stuck in the nearest lymph nodes. This is why doctors check the lymph nodes first when they are working out how far a cancer has grown or spread

5. White Blood Cells and Antibodies
White blood cells produce antibodies- proteins used by immune system to identify and neutralize foreign invaders
Antibodies prevent invaders from entering or damaging cells by binding to them; stimulate removal of invader by other cells; trigger destruction of invader by stimulating immune responses
Antibodies specific to antigens

6. Spleen
Filters blood to take out worn out red blood cells- Red blood cells are replaced by new ones made in the bone marrow
Filters out bacteria, viruses, and other foreign particles
White blood cells in spleen attack bacteria and viruses as they pass through

7. Thymus Small gland under breastbone Helps produce white blood cells
Most active in teenagers and shrinks in adulthood

8. Tonsils and Adenoids Two glands at back of throat
Protects entrance to digestive system and the lungs from bacteria and viruses

9. Vaccines Immunity booster to a certain virus
Can be to prevent or improve the effects of a future infection
Can be therapeutic ex. Vaccines against cancer

10. Types of Vaccines
Can be dead or inactivated organisms or purified products of them
Containing killed microorganisms
Containing live modified organisms
Containing inactivated toxic compounds ex. Tetanus
fragmented

11. Developing Immunity
Immune system recognizes vaccines as foreign, destroys them, ‘remembers’ them
Upon entry of virus, immune system recognizes foreign invaders, neutralizing and destroying cells infected by them

12. Efficacy of Vaccines
Vaccines do not guarantee complete protection from a disease
Sometimes the immune system does not respond properly or at all ex. low immunity due to diabetes, steroid use, HIV infection

13. Typical Vaccinations Polio Hepatitis A,B Tetanus Diphtheria
Chicken pox

14. In class work
P.196
Questions 16 & 17