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51 Cards in this Set
- Front
- Back
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Main functions of the Lymphatic System (3)
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1. Return excess tissue fluid and leaked plasma proteins to the bloodstream
2. Work along with the immue system to combat disease. (THE defense mechanism) 3. Lacteals recieve all lipid and lipid soluble vitamins absorbed by the small intestine. |
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lymphatic plexus
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networks of lymphaitc capillaries that originate in the extracellular or intracellular spaces of most tissues
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components of lymphatic capillaries
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formed of highly attenuated (tapered) endothelium lacking basement membrane so that fluid, plasma proteins, bacteria and cellular debris can enter them
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relation of lymphatic capillaries with capillary beds
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closely associated
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excess of interstitial fluid, which manifests as swelling
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edema
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location of lyphatic vessels
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present everywhere blood capillary beds are found
exceptions: teeth, bone, bone marrow and CNS |
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CNS excess fluid drainage
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excess fluid in the CNS is drained by the cerebrospinal fluid
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Vessel appearance
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beaded from the buldging at the location of the closely spaced valves
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Lymph vessel drainage direction
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form a one-way system in which lymph flows only toward the heart
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number of tunics present
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similar to capillaries (have three tunics) but their walls are distinctly thinner.
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observation on gross level
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most cannot be seen on the gross level
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The tissue fluid entering into the lymphatic capillaries and conveyed by lymphatic vessels
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Lymph
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Properties of lymph
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1. clear, watery, and slightly yellow
2. similar in composition to blood plasma 3. three liter of lymph is returned to the venous system each day 4. one way systems (no backflow) - lacks a pump - relies on skeletal muscle contractions, pulsations by arteries, or expansion of lungs |
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when transport of lyph is blocked or inhibited
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lymphedema (an accumulation of lymph in the tissue) occurs
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Lymph nodes
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small masses of lymphatic tissue located along course of lymphatic vessels
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function of lymph nodes (2)
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1. filters lymph on its way to the venous system (all lymph must pass through AT LEAST one lymph node)
2. lyphocytes monitor lymph nodes for presence of antigens and mount an attack against them if found |
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Afferent lymphatic vessels
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bring lymph TOWARDS the lymph nodes
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Efferent lymphatic vessels
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take lymph AWAY from the lymph nodes to the venous circulation
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lymphocytes
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circulating white blood cells of the immune system that recognize foreign materials, or atigens, and react to their potentially harmful presence in a highly specific manner
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how do lymphocytes enter lymph nodes?
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1. via AFFERENT lymphatic vessels
2. MOST enter from blood circulation via postcapillary venules (AKA high endothelial venules HEVs) |
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B-lymphocytes
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differentiated in bone marrow (note B for bone); produce plasma cells which secrete antibodies; concentrated in outer cortex of lymph node
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T-lymphocytes
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formed in the bone marrow but differentiated in the thymus (note T for thymus) these cells function in cell-mediated immune response to act against viruses or tumor cells; reside in the inner cortex of the lymph node
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Natural Killer Cells
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recognize and kill transformed cells
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right lymphatic duct
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drains lymph from the body's right upper quadrant (right side of head, neck, thorax, and right upper limb) above the diaphragm
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Afferent lymph vessel dump lymph into...
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the subscapular sinus
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where does the right lymphatic duct join the venous circulatory system?
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At the root of the neck it enters the junction of the right internal jugular and right subclavian veins (called the right venous angle)
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Thoracic duct
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the larges lymph vessels which drains lyphm from remainder of the body (75%)
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chyle cistern
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dilated collecting sac formed by lymphatic trunks draining the lower half of the body which merge in the abdomen (found anterior to L1-L2)
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Thoracic duct location
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between the descending aorta and the azygous vein and ascends in the posterior mediastinum
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where does the thoracic duct join the venous circulatory system?
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ends at the junction of the left internal jugular and left subclavian veins (called the left venous angle)
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lymphoid tissue
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aggregrations of lymphatic tissue that produce lymphocytes located throughout the body; most of this tissue contains ceticular fibers (not in the thymus)
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Lymphocytes are produced from...
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stem cells in bone marrow and comprise 20-50% of WBCs in blood.
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Lymphocyte nuclei are...
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ovoid and often slightly indented with dense chromatin. The nucleus is approximately 90% of the cell volume with very little cytoplasm
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Specialized cells in the endothelium of high endothelial venules signal lymphocytes to...
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to leave the circulation and enter the lymph node
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T-lymphoctes
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are for humoral immunity
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Immuno-competent lymphocytes enter the blood and lymph circulation and undergo...
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antigen-dependent activation
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Lymph drains from superficial vessels following...
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veins
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Lymph drains from deep lymphatic vessels following...
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arteries
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Thymus
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DOES NOT CONTAIN RETICULAR FIBERS
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bone marrow
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location where lymphocytes are produced from stem cells.
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Immunocomptent cells can distinguish from...
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self (molecules normally presnet within an organism) and non-self (molecules NOT normally present)
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Thymus
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location where T-lymphocytes become immunocompent
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thymus size increases....
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until approx age 8
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after max size is reached the thymus...
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is replaced by fibrous and fatty connective tissue
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Spleen
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larges lymph organ which has both immune and hemopoietic (forms blood cells) functions
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functions of spleen (6)
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1. cleans blood
2. removes debris, foreign matter, bacteria, viruses, toxins, etc. 3. stores breakdown products for red blood cells for later reuse 4. erythrocyte production in fetus (normally ceases after birth) 5. stores blood platelets 6. contains lyphocytes and macrophages (filters blood like lymph nodes filter lymph) |
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tonsils are an
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intramucosal collection of lymphocytes closely associated with the overlying epithelium
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different tonsils...
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1. palatine
2. pharyngeal 3. palatal 4. lingual |
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palatine, pharyngeal, palatal, and lingual tonsils form the...
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lymphoepithelial ring in the pharynx
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tonsils prevent...
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pathogens in respiratory and digestive tracts from penetrating mucous membrane lining
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most lymph nodes are named...
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according to their location
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