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17 Cards in this Set
- Front
- Back
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Functions of Lymphatic System? |
Fluid Balance- 30L of fluids pass from blood capillaries to interstitial space per day 27 returns to capillaries, 3L enteres lymphatic system Lymph passes through lymphatic vessels to return to blood Defend Body- Microorganisms and other foreign substances filtered from lymph by Lymph nodes and from blood by spleen Produces and stores immune cells (primary function) Fat absorption- Absorbs fat and other substances from digestive tract Lymph has milky appearance due to fat |
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How is lymph transported? |
By lymphatic capillaries and vessels These carry lymph from peripheral tissues to venous system |
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Describe lymphatic vessels |
Vessels: Vessels get less large and less numerous as they converge Resemble small veins Beaded appearance due to valves If vessel is compressed, valve prevents backflow |
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HOW ARE lymphatic vessels SIMILAR TO ARTERIES AND VEINS? |
Both transport fluids
-Veins lead back to heart, lymph vessels will eventually empty into ducts -More lymph vessels than veins |
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What are Lacteals? |
Lacteals: special lymphatic vessels in lining of small intestines, fat enters lacteals, passes through lymphatic vessels to venous circulation
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What is lymph and how is it formed? |
It is water and solutes- resmebles plasma but lower concentration of proteins Solutes come from 2 sources- blood and cells within tissues |
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What are lymphatic capillaries? |
Capillaries:
Simple squamous epithelium More permeable than blood capillaries Found in all tissues except CNS, (BM??) and tissues w/o blood vessels (epidermis and cartilage) Lymph capillaries are larger in diameter than blood capillaries, have thinner walls. They don't contain muscle cells. |
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Lymph from where drains to which area? |
Vessels converge and empty into blood at two locations
Right lymphatic duct Lymph from upper right limb, right ½ of head, neck and chest Empties into R subclavian vein Thoracic Duct Vessels from rest of body Empty into left subclavian vein |
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Describe structure and function of Tonsils |
Protect against pathogens and other material from entering nose and mouth |
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Describe structure and function of Lymph Nodes |
Rounded structures, distributed throughout body Afferent Lymph vessel carries lymph to Lymph node Efferent lymph vessel carries lymph away Act as water filters, purifying lymph before it reaches venous circulation 99% of antigens are removed from lymph Fixed macrophages in sinuses engulf debris Antigen is processed and presented to nearby lymphocytes by macrophages= antigen presentation. --This is the first step in activation of immune response, Stimulates lymphocyte activity |
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Describe structure and function of Thymus |
In mediastium Size is dependent on age Largest relative to body size is at 1-2 years Continues to grow until puberty After puberty, starts to decrease in size and become more fibrous Older adults, it may not even be visible and more susceptible to disease It is the production site of and maturation of lymphocytes Releases thymic hormones which causes T cells to mature Doesn't respond to foreign substances After maturation, cells enter blood and travel to lymphatic tissues and help defend body against specific pathogens |
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Describe structure and function of the Spleen |
Contains largest collection of lymphoid tissue in body Filters blood, not lymph Removes abnormal blood cells and blood components by phagocytosis Storage of iron recycled from RBC's Initiation of immune response by B cells and T cells in response to specific antigens in circulating blood |
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What are the three classes of lymphocytes? |
T cells (thymus dependent)
B cells (BM derived)- differentiate into plasma cells which produce and secrete antibodies NK cells (natural killers)- police peripheral tissue |
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What are the types of T cells? |
Cytotoxic T cells: Attack foreign cells or cells infected with viruses Helper T cells: Stimulate activation and function of T and B cells Suppressor T cells: Inhibit activation and function of T and B cells |
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How long do do lymphocytes live and where are they produced? |
Long life spans 80% live 4 years, some past 20 Produced in Bone marrow and lymphoid tissue |
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What is Innate immunity? |
Born with Non specific- can't distinguish one threat from another Response is always same Includes physical barriers, phagocytic cells, interferons, complement |
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What is adaptive immunity? |
Acquired Protect against specific threats Develop after birth Depends on activation of specific lymphocytes |
