Flashcards in Exam 3: Lymphatic System Deck (30)
1
Capillary Level
-fluids pushed out of vessels and into tissues
2
Interstitial Fluid
-fluid within tissues
-venules pick up most, but not all of this fluid
3
Lymph
-interstitial fluid picked up by lymphatic system
4
Lymphatic System (consists of)
-consists of lymph vessels and lymphatic tissues and organs
5
Functions of Lymphatic System
-absorbs dietary lipids and fat-soluble vitamins (A, D, E, K)
-returns interstitial fluid back into blood stream (done by lymph vessels)
-initiates an immune response when mecessary (done by lymphatic tissues/organs)
6
Lymph Vessels (system)
-low pressure system
7
Lymphatic Capillaries
-smallest lymph vessel
-wall composed of endothelium (simple squamous)
-walls have 1-way flaps which allow lymph to enter but not escape
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Lacteals
-lymphatic capillaries in small intestine
-function absorb dietary fats
9
Lymphatic Vessels (characteristics)
-like veins, have 3 tunics
-have valves which prevent backflow
-take lymph to and from lymph nodes
10
Lymphatic Trunks
-formed from merging lymphatic vessels
-drain into lymphatic ducts
11
Lymphatic ducts
-Right Lymphatic Duct
-Thoracic Duct
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Right Lymphatic Duct
-receives lymph from right side of head, neck and thorax, right upper limb
-drains into right subclavian vein
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Thoracic Duct
-receives lymph from left side of head, neck, thorax, left upper limb, entire abdomen, left and right lower limbs
-drains into left subclavian vein
14
Lymphedema
-buildup of interstitial fluid due to lymph vessel damage
-causes: surgery that removes lymph vessels (eg for breast cancer), cancer spread, infection from parasitic worms (filarial worms)
15
Pathway of Lymph
-lymphatic capillaries-->lymphatic vessels-->lymphatic trunks-->lymphatic ducts-->venous circulation
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Lymphatic Cells
-start and produce immune response when exposed to antigens
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Antigens
-anything perceived as foreign in the body
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Lymphocytes
-T-lymphocytes (T-cells)
-B-lymphocytes (B-cells)
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T-Lymphocytes
-mature in thymus
-functions: some of these cells manage/direct an immune response, while others directly attack cells
-general/soldiers
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B-Lymphocytes
-mature in red bone marrow
-function: many secrete antibodies which attach to antigens and immobilize them until another cell destroys antigen
-handcuffs
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Macrophages
-monocytes that migrated from bloodstream into other tissues
-function: phagocytize foreign substances
22
Lymphatic Structures
-not organs
-consists of connective tissue containing lots of lymphatic cells
-not surrounded by CT capsule
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Lymphatic Nodules
-main type of lymphatic structures
-clumps of lymphatic cells within other organs
-ex: tonsils in pharynx, MALT (Mucosa Associated Lymphatic Tissue) in walls of GI and respiratory tract
-both respond to antigens
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Lymphatic Organs
-lymphatic structures surrounded by connective tissue capsule
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Thymus
-behind sternum
-function: T-lymphocytes mature and differentiate here. this happens prior to adult hood
-adult thymus is non functional
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Lymph Nodes
-tiny oval organs
-hundreds
-found in clusters
-connect with lymphatic vessels
-functions: filter lymph, activate immune response if antigens found in lymph
-infection: lymph nodes become swollen and tender
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Cancer Spread and Lymph Nodes
-cancer can spread through lymph vessels and lymph nodes
-cancerous lymph nodes tend to be hard and nontender
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Spleen
-largest lymphatic organ in body
-located in upper left abdomen, behind and lateral to stomach
-red pulp and white pulp
-functions: does NOT filter lymph, it filters blood
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Red Pulp
-splenic sinusoids (large capillaries) and splenic cords
-contains erythrocytes, platelets and macrophages
-function: removes old erythrocytes and platelets
-graveyard for erythrocytes
30