2.  Circulates body fluids; transports wastes, fats, etc. › Fluid inside is called lymph.  Fights infectious diseases; launches attacks against foreign objects.

3.  Lymphatic capillaries – located near and around blood capillaries.  Pick up tissue fluid from the area and absorbs it into lymph.

4.  Lymphatic capillaries merge to form lymphatic vessels › Have valves like veins.  Larger vessels lead to lymph nodes.  Vessels merge to form lymphatic trunks.

5.  Lymphatic trunks join with collecting ducts before being emptied into the veins.  Two collecting ducts › Thoracic › Right lymphatic

6.  Thoracic – larger and longer › Lymph from lower limbs, abdominal region, left upper limb, left thorax, head, and neck. › Empties into the left subclavian vein.  Right Lymphatic – much smaller area › Lymph from right side of the head, right upper limb, right thorax. › Empties into the right subclavian vein.

7.  Tissue fluid › Originates from blood plasma – water and dissolved substances that are released by blood capillaries.  Lymph fluid › Tissue fluid is pushed into the lymph capillaries where it becomes lymph.

8.  Transports proteins back to the blood.  Transports bacteria and other foreign objects into lymph nodes.  Basically, the purpose of lymph is to cleanse the blood plasma and return it to the cardiovascular system.

9.  Lymph is driven into capillaries by hydrostatic pressure of the tissue fluid.  Once inside, it’s moved by muscle contractions (like in veins).  It is also moved by pressure changes that come along with breathing.  If lymph doesn’t move properly, it can back up and cause inflammation (edema).

10.  Function: filter harmful particles; monitor body fluids; make lymphocytes.  Located in groups of chains along larger lymphatic vessels.

11.  Bean-shaped  < 2.5 cm long  Enclosed by connective tissue capsule.  Hilum – indentation where blood vessels and nerves join a lymph node

12.  Vessels leading in (afferent) come in at many different points.  Vessels leading out (efferent) exit at one point – the hilum.

13.  Inside: › Lymph nodules – masses of B cells and macrophages that fight disease › Lymph sinuses – complex network of channels for lymph to travel.

14.  Nodes are often removed in procedures that remove cancerous cells from nearby tissues and organs.

15.  Soft, bi-lobed gland enclosed in a capsule located behind the sternum  Makes T-cells which aid in immunity.  Larger in childhood and infancy. Shrinks throughout life.

16.  Function: Filters blood  Largest lymphatic organ.  Looks like a large node.  Two tissue types: › White pulp – nodules packed with lymphocytes › Red pulp – fills the rest of the space; RBC’s, lymphocytes, and macrophages.

17.  Both work together to fight infections.  Pathogens – disease-causing agents

18.  General  Responds quickly  Protect against many kinds of pathogens.  Species resistance, chemical barriers, mechanical barriers, natural killer cells, inflammation, phagocytosis, and fever.  Precise  Develops slowly  Targets specific pathogens  Provides adaptive defense/immunity. Innate (Nonspecific)Adaptive(Specific)

19. Type of DefenseDescriptionExample Species Resistance Mechanical Barriers Chemical Barriers Natural Killer (NK) cells Inflammation Phagocytosis Fever

20.  First line of defense – mechanical barriers  Second line – chemical barriers, NK cells, inflammation, phagocytosis, fever  Third line - immunity

21.  Antigens – large proteins and other molecules that invade the body. › The body recognizes and catalogues non-harmful substances before birth.  Large and complex antigens are more likely to illicit a response.  Hapten cells can aid in attacking the body; smaller; will not illicite a response on their own. The Enemy

22.  Lymphocytes – T cells and B cells.  T-Cells – Originally formed in red bone marrow and mature in the thymus.  B-Cells – Formed and matured in red bone marrow.  Both reside in lymphatic organs. The Remedy

23.  Activation requires an antigen- presenting cell (macrophage or B cell.)  T cells come in direct contact with cells (cellular immune response)  3 kinds › Helper cells – stimulate B cells to attack › Cytotoxic cells – Attack tumor and viral cells › Memory cells – Remain to attack already dealt-with cells with a quicker response.

24.  B cells activate and produce clones of themselves.  Most need helper T cells to activate.  Some become plasma cells that release antibodies.  Memory B cells – ready to respond to future encounters with the same antigen.

25.  Antibodies/Immunoglobins – same thing!  Antibodies do three things: › Directly attack antigens › Activate complement › Stimulate localized changes (inflammation)

26.  Immunoglobin G (IgG) – fights bacteria, viruses, and toxins  IgA – in breast milk, tears, nasal fluid, intestinal juice, urine, etc  IgM – fights food antigens and bacteria  IgD – mostly in infants; activates B cells  Ig E – associated with allergic reactions

27.  Active immunity – longer term  Naturally acquired active immunity – when someone develops immunity based on their own body producing the antibodies needed.  Artificially acquired active immunity – when someone develops immunity because of a vaccine

28.  Passive Immunity – shorter term  Artificially acquired passive immunity – individual receives a different individual’s antibodies  Naturally acquired passive immunity – passed from mother to child during pregnancy

29.  Immune response to a nonharmful substance  Unlike normal responses, they can damage tissue  Allergens – antigens that trigger an allergic response

30.  Delayed-reaction allergy – due to long exposure › Household chemicals, cosmetics, poison ivy  Immediate-reaction allergy – occurs within minutes › Tendency to overproduce IgE › Insect stings, penecillin

31.  Occur after organ transplants  Immunosuppressive drugs are used to avoid rejection  Rejection can take place years after the organ is transplanted.

32.  The body can begin to attack itself.  About 5% of the population has an autoimmune disease › Diabetes, lupus, rheumatoid arthritis  How? Viruses can take on part of an immune system’s antibodies. Other antibodies kill the viral cells and recognize it (even the good part) as an invader