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51 Cards in this Set

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Main functions of the Lymphatic System (3)
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.
lymphatic plexus
networks of lymphaitc capillaries that originate in the extracellular or intracellular spaces of most tissues
components of lymphatic capillaries
formed of highly attenuated (tapered) endothelium lacking basement membrane so that fluid, plasma proteins, bacteria and cellular debris can enter them
relation of lymphatic capillaries with capillary beds
closely associated
excess of interstitial fluid, which manifests as swelling
edema
location of lyphatic vessels
present everywhere blood capillary beds are found
exceptions: teeth, bone, bone marrow and CNS
CNS excess fluid drainage
excess fluid in the CNS is drained by the cerebrospinal fluid
Vessel appearance
beaded from the buldging at the location of the closely spaced valves
Lymph vessel drainage direction
form a one-way system in which lymph flows only toward the heart
number of tunics present
similar to capillaries (have three tunics) but their walls are distinctly thinner.
observation on gross level
most cannot be seen on the gross level
The tissue fluid entering into the lymphatic capillaries and conveyed by lymphatic vessels
Lymph
Properties of lymph
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
when transport of lyph is blocked or inhibited
lymphedema (an accumulation of lymph in the tissue) occurs
Lymph nodes
small masses of lymphatic tissue located along course of lymphatic vessels
function of lymph nodes (2)
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
Afferent lymphatic vessels
bring lymph TOWARDS the lymph nodes
Efferent lymphatic vessels
take lymph AWAY from the lymph nodes to the venous circulation
lymphocytes
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
how do lymphocytes enter lymph nodes?
1. via AFFERENT lymphatic vessels
2. MOST enter from blood circulation via postcapillary venules (AKA high endothelial venules HEVs)
B-lymphocytes
differentiated in bone marrow (note B for bone); produce plasma cells which secrete antibodies; concentrated in outer cortex of lymph node
T-lymphocytes
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
Natural Killer Cells
recognize and kill transformed cells
right lymphatic duct
drains lymph from the body's right upper quadrant (right side of head, neck, thorax, and right upper limb) above the diaphragm
Afferent lymph vessel dump lymph into...
the subscapular sinus
where does the right lymphatic duct join the venous circulatory system?
At the root of the neck it enters the junction of the right internal jugular and right subclavian veins (called the right venous angle)
Thoracic duct
the larges lymph vessels which drains lyphm from remainder of the body (75%)
chyle cistern
dilated collecting sac formed by lymphatic trunks draining the lower half of the body which merge in the abdomen (found anterior to L1-L2)
Thoracic duct location
between the descending aorta and the azygous vein and ascends in the posterior mediastinum
where does the thoracic duct join the venous circulatory system?
ends at the junction of the left internal jugular and left subclavian veins (called the left venous angle)
lymphoid tissue
aggregrations of lymphatic tissue that produce lymphocytes located throughout the body; most of this tissue contains ceticular fibers (not in the thymus)
Lymphocytes are produced from...
stem cells in bone marrow and comprise 20-50% of WBCs in blood.
Lymphocyte nuclei are...
ovoid and often slightly indented with dense chromatin. The nucleus is approximately 90% of the cell volume with very little cytoplasm
Specialized cells in the endothelium of high endothelial venules signal lymphocytes to...
to leave the circulation and enter the lymph node
T-lymphoctes
are for humoral immunity
Immuno-competent lymphocytes enter the blood and lymph circulation and undergo...
antigen-dependent activation
Lymph drains from superficial vessels following...
veins
Lymph drains from deep lymphatic vessels following...
arteries
Thymus
DOES NOT CONTAIN RETICULAR FIBERS
bone marrow
location where lymphocytes are produced from stem cells.
Immunocomptent cells can distinguish from...
self (molecules normally presnet within an organism) and non-self (molecules NOT normally present)
Thymus
location where T-lymphocytes become immunocompent
thymus size increases....
until approx age 8
after max size is reached the thymus...
is replaced by fibrous and fatty connective tissue
Spleen
larges lymph organ which has both immune and hemopoietic (forms blood cells) functions
functions of spleen (6)
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)
tonsils are an
intramucosal collection of lymphocytes closely associated with the overlying epithelium
different tonsils...
1. palatine
2. pharyngeal
3. palatal
4. lingual
palatine, pharyngeal, palatal, and lingual tonsils form the...
lymphoepithelial ring in the pharynx
tonsils prevent...
pathogens in respiratory and digestive tracts from penetrating mucous membrane lining
most lymph nodes are named...
according to their location