1. Anatomy and Physiology
March 23rd and 24th, 2015
The Lymphatic and immune systems

2. Schedule for Remainder of the Quarter
3/23 and 3/24
Lymphatic and immune system
3/25 and 3/26
3/27
Review Cardiovascular, blood, lymphatic and immune system
3/30 and 3/31
Quarter 3 final exam
4/1 and 4/2
Documentary “Bad Blood”

3. Lymphatic System
Collection of cells and biochemical that travel in lymphatic vessels and the organs and glands that produce them
Assists in circulating body fluids
Closely associated with the cardiovascular system
Transports excess fluid from tissues back into the blood
Lacteals absorb digested fats and transport them to the venous circulation

4. Lymphatic system organization
Lymphatic capillaries – collect fluid from tissues
Lymphatic vessels – similar to veins, contain valves, lead to lymph nodes
Lymphatic trunks – drain fluid from lymphatic vessels

5. Lymphatic system organization cont…
Collecting ducts – final location before being emptied into venous system
Thoracic duct - Collects from lower body, abdomen, left upper limb, left side of thorax, head, neck
Right Lymphatic Duct - Collects from right side of head and neck, right upper limb and right thorax

6. Movement of Lymph
Primarily flows due to pressure caused by skeletal muscles contracting and breathing
Blockage of Lymphatic pathways or removal of lymphatic vessels can result in fluid buildup in the area know as edema

7. Lymph Nodes
Located all throughout the body along the lymphatic pathways except for in the central nervous system
Contain large numbers of lymphocytes (b and t cells) and macrophages
Tonsils are partially encapsulated lymph nodes

8. Lymph Nodes
Functions
Filtering potentially harmful particles from lymph before returning it to the blood stream
Monitoring body fluids (immune surveillance) provided by lymphocytes and macrophages
Site of lymphocyte production

9. Other Lymphatic Organs
Thymus
Soft gland that Is large during infancy but drastically shrinks through adulthood
Produces some mature t-cells
Spleen
Largest lymphatic organ
White pulp – similar to lymph nodes, packed with lymphocytes
Red pulp – contains RBC’s, plus lymphocytes and macrophages
Responsible for filtering the blood, removing and recycling old RBC’s

10. Questions???

11. The Immune System
Protection against pathogens – disease causing agents such as viruses, bacteria, fungi and protozoans
Additional protection against cancer cells to some extent

12. Innate immunity (non-Specific)
Mechanical barriers – skin, mucous membranes (1st Line of Defense)
Chemical Barriers – enzymes, gastric juice, salt, sweat, interferons, Complement
Natural killer cells – lymphocytes that defend against viruses and cancer cells
Inflammation – redness, swelling, heat, pain; attracts phagocytes and fibrinogen
Phagocytosis – neutrophils, monocytes and macrophages engulf and destroy
Fever – increased temperature makes environment inhospitable and increases activity of phagocytes

13. Acquired immunity (Specific)
Antigens
Components located on cell surfaces
Before birth, cells identify certain molecules as “self”
Non-Self or foreign antigens are detected

14. T-Lymphocytes or t-cells
Originates in Bone Marrow
Differentiates in Thymus
70-80% of Lymphocytes
Provides cellular immunity by directly interacting with antigens or antigen bearing agents to destroy them
Three Main Types
Helper – stimulate b-cells to produce antibodies
Cytotoxic – bind to antigen bearing cells and destroy them
Memory – remain inactive until subsequent exposure to same antigen

15. B-Lymphocytes or b-cells
Originates and differentiates in bone marrow
20-30% of lymphocytes
Provides Humoral immune response by interacting indirectly producing antibodies that destroy the antigens or antigen bearing agents
Becomes activated when encountering an antigen or helper t-Cell associated with the same antigen
Two main types
Memory – remain inactive until subsequent exposure
Plasma – produce antibodies or immunoglobulins
Can produce up to 2000 antibodies per second

16. Antibodies (Ab) IgG AKA immunoglobulins (Ig)
Proteins produced by plasma cells in response to a specific antigen (Ag)
Antibodies [Ab] frequently measured as a diagnostic tool
Serology
High IgM can signal current primary infection
High IgG can signal current secondary infections
IgG

17. 5 subclasses of Igs:
IgG: main Ab (75%) in serum; + main Ab during 2o response (passive immunity from mother)
IgA: main Ab in external secretions including breast milk
IgE: main Ab in allergic reactions (associated with histamine)
IgM: Ab on virgin B-cells; + main Ab during 1o response, anti-a and anti-b are this type
IgD: Ab on virgin B-cells, important for activation

19. Immunity can be naturally or artificially acquired
Immunity can be naturally or artificially acquired. Also, immunity can be active or passive. Active immunity lasts for a long time. This is often many years to a lifetime. In active immunity the body makes its own antibodies. Passive immunity is short term. It typically lasts for just a few months. In passive immunity antibodies are borrowed from someone else. A natural way to get active immunity is have a disease and survive. After that time you will make antibodies to the pathogen. A natural way to get passive immunity is when antibodies pass from the mother to the fetus across the placenta. An artificial way to get active immunity is to be vaccinated with dead or weakened pathogen. An artificial way to get passive immunity is to receive an injection of antibodies made by someone else. Gamma globulin is the portion of serum that contains antibodies.

20. Allergic Reactions
Immune response to non harmful substance called allergen
Delayed reaction – result from repeated exposure
Immediate reaction
Occurs within minutes
Overproduction of ige antibodies
Mast cells and basophils release histamine
Causes inflammation, smooth muscle contraction and increased mucous production

21. Transplantation and tissue rejection
MHC antigen on cell surfaces must match for proper transplantation
Immunosuppressive drugs reduce the risk
Graft vs. host disease
Cells in implanted bone marrow attack host body

22. Autoimmunity
Type1 diabetes, rheumatoid arthritis and systemic lupus erythematosus
Antibodies and Cytotoxic t-cells see “self” antigens as “non-self” and attack