1. Lymphatic system and body defense
By: Audrey McNicholl and Megan Saunders

2. Functions of the Lymphatic System
The lymphatic system returns excess interstitial fluid to the blood, absorbs fats and fat- soluble vitamins, and provides defense against disease

3. Components
Lymph is the fluid in the lymphatic vessels. It is picked up from the interstitial fluid and returned to the blood plasma
Lymphatic vessels carry fluid away from the tissues
The right lymphatic duct drains lymph from the upper right quadrant of the body. The thoracic duct drains all the rest
Lymph enters a lymph node through afferent vessels, filters through the sinuses, and leaves through an efferent vessel

4. Components

5. Components cont.
Lymph nodes filter and cleanse the lymph before it enters the blood
Tonsils are clusters of lymphatic tissue associated with openings into the pharynx and provide protection against pathogens that may enter through the nose and mouth
When the tonsils become enlarged they may interfere with breathing and are called adenoids
The spleen is a lymph organ that filters blood and also acts as a reservoir for blood

6. Resistance to Disease
The ability to counteract pathogens is resistance
Susceptibility is a lack of resistance
Barriers that deter microbial invasion may be mechanical (skin), fluid (tears), or chemical (lysozymes)
Interferon has particular significance because it offers protection against viruses
Interferon is produced by virus-infected cells to provide protection for the neighboring cells

7. Resistance to disease cont.
Inflammation is a nonspecific body defense mechanism that occurs in response to tissue damage from microorganisms or trauma
Localized inflammation is contained in a specific region
Inflammation sets the stage for tissue repair and usually happens when tissues are damaged

8. Steps in inflammation

9. Specific Defense Mechanisms
Specific defense mechanism provide the third line of defense against microbial invasion. This third line defense is specific resistance, or immunity
Specificity and memory are two characteristics of specific defense mechanisms. The two primary cells that are involved and lymphocytes and macrophages
A molecule that is interpreted as nonself and that triggers an immune response is called a foreign antigen
Antigens are molecules that trigger an immune response

10. Development of lymphocytes
Like all other blood cells, lymphocytes develop from stem cells in the bone marrow
During fetal development, the bone marrow releases immature and undifferentiated lymphocytes into the blood, some go on to become T cells and some B cells
T cells are responsible for cell mediated immunity in which the T cells directly attack the invading antigens
B cells are responsible for anti-body mediated immunity

11. Devp. Of lymphocytes

12. Acquired Immunity
4 different kinds of ways to acquire specific resistance, or immunity
The terms active and passive refer to whose immune system reacts to the antigen
Active immunity occurs when the individual’s own body produces memory T cells and B cells in response to a harmful antigen
Active immunity takes several days to develop but lasts a long time
Passive immunity results when the immune agents develop in another person and are transferred to an individual who was not previously immune
Passive immunity is immediately effective but does not last long

13. Acquire immunity cont.
The terms natural and artificial refer to how the immunity is obtained
Natural immunity is acquired through normal activities
Artificial immunity requires some deliberate action

14. Chapter Recall Lymph Capillaries
Collects lymph from three-fourths of the body
Enlarged Pharyngeal tonsils
Lack of resistance
Provides localized protection against viruses
Cause an increase in body temperature
Principal cell involved in cell-mediated immunity
Protein that triggers an immune response
Produce antibodies
Rapid, intense reaction against an antigen
Adenoids
Antigen
Interferon
Lacteal
Plasma cells
Pyrogens
Secondary response
Susceptibility
T cells
Thoracic duct

15. Answers Lymph Capillaries D-Lacteal
Collects lymph from three-fourths of the body J-Thoracic Acid
Enlarged Pharyngeal tonsils A-Adenoids
Lack of resistance H-Susceptibility
Provides localized protection against viruses C-Interferon
Cause an increase in body temperature F-Pyrogens
Principal cell involved in cell-mediated immunity I-T cells
Protein that triggers an immune response B-Antigen
Produce antibodies E-Plasma Cells
Rapid, intense reaction against an antigen G-Secondary Response