Where can MALT (Mucosa-associated lymphoid tissue ) be found?
Walls of the bronchi (Respiratory) ; Walls of pharnyx (tonsils); walls of small intestines (Peyer's Patches); wall of the colon (aggregate lymphoid nodules); walls of appendix; walls of vagina
Isolated clusters of lymph follicles found in the wall of the small intestines are called ____________
Peyer's patches are clusters of lymphoid tissue found primarily in the __________________________
The lymphatics function is to _________________________________________________
absorb the excess protein-containing interstitial fluid and return it to the bloodstream.
The distal portion of the small intestine contains clumps of lymph follicles called ________.
Both lymph and venous blood flow are heavily dependent on ________.
skeletal muscle contractions and differences in thoracic pressures due to respiratory movement
What lymphatic structure drains lymph from the right upper limb and the right side of the head and thorax?
Right lymphatic duct
The thymus initially ___________ in size and then ___________ in size from ______________ through old age.
increases; decreases; adolescence
List the 7 functions of the spleen.
■Site of lymphocyte proliferation
■Immune surveillance and response
■Cleanses the blood
■Stores breakdown products of RBCs for later reuse
■Spleen macrophages salvage & store Fe for use by bone marrow
■Site of fetal erythrocyte production (normally ceases after birth)
■Stores blood platelets
When the lymphatics are blocked due to tumors, the result is ________.
severe localized edema distal to the blockage
2 methods in which lymph is transported
By the pulsations of nearby arteries & by the contractions of smooth muscle in the walls of the lymphatics
A ring of lymphoid tissue that appears as a swelling of the mucosa in the oral cavity is called a(n) ________.
Lymph collecting or pooling from the lower extremities would first pool in the ________ before moving on up.
Name 3 areas where particularly large clusters of lymph nodes occur?
Axillary, Cervical & Inguinal Areas
What is the function of MALT (Mucosa-associated lymphoid tissue)
To protect the digestive and respiratory systems from foreign matter
Highly specialized lymph capillaries called ________ are present in the villi of the intestinal mucosa.
Lymph nodes have more ________ lymphatic vessels than ________ lymphatic vessels.
Of the organs in the lymphatic system, only the ________ becomes less important as you get older.
Hassall's corpuscles are always found in the lighter-colored ________ regions of the thymus.
Describe the structural and functional relationship of the vessels of the blood vascular system and the lymphatic system.
Lymphatic fluid is moved through the lymphatics by the milking action of active skeletal muscles, pressure changes within the thorax during breathing, valves to prevent backflow, and pulsation of adjacent arteries
List 4 mechanisms by which lymphatic fluid is moved through the lymphatics
Milking action of active skeletal muscles, pressure changes withinthe thorax during breathing, valves to prevent backflow and pulsation of adjacent arteries.
What is the consequence of obstruction of the lymphatics?
Obstruction of the lymphatics results in edema distal to the obstruction.
Where are the lymph node aggregations most dense?
Lymph node aggregations are most dense near the body surface in the inguinal, axillary, and cervical regions of the body
What is the special role of the thymus gland?
To secrete hormones, the thymus gland causes T lymphocytes to become immunocompetent
Name the tonsils and state their body locations.
Palatine tonsils are located on either side at the posterior end of the oral cavity. The lingual tonsils lieat the base of the tongue. The pharyngeal tonsils are in the posterior wall of the nasopharynx.
describe the functions of the spleen?
The spleen's main functions are to remove aged or defective blood cells and platelets from the blood & to store or release some of the breakdown products of th RBCs to the blood for processing by the liver. Other functions include: acting as a blood filter & reservior, serving as a site for production in developing embryos, storing blood platelets, and providing a site for lymphocyte proliferation & immune surveillance & response
Describe lymph transport in terms of rate, volume, and ability to change.
Rate: Slow (125 ml/hour) Volume: 3 liters of lymph enters the bloodstream in a 24-hour period * Change: An increase in physical activity will cause lymph flow to increase, balancing the greater rate of fluid outflow from the vascular system.
In the thymus, what is the difference in the lymphocyte density of the cortex versus the medulla?
The cortex contains densely packed, rapidly dividing lymphocytes; the medulla contains fewer lymphocytes
How does the lymphatic system both help and hinder the spread of cancer through the body?
Lymph nodes help rid the body of cancer cells by immune mechanisms. Lymph vessels may also be used to spread cancer cells throughout the body if immunity is not effective against the cancer cells.
How does the structure of a lymph node allow lymphocytes and macrophages to perform their protective function?
Macrophages ingest microorganisms and cellular debris. Lymphocytes monitor the lymphatic stream for the presence of antigens and mount an immune response. Because there are fewer efferent vessels draining the node than afferent vessels that feed it, the flow of lymph through the node stagnates somewhat, allowing time for the lymphocytes and macrophages to work.
Condition caused by parasitic worms that get in the lymph system and reproduce to proportions that block the vessels. The swelling is due to edema
Explain why it is good when cancer has not metasized to the lymphatic system?
The lymphatic system consists of a meandering network of lymphatic vessels. Cancer cells that break free from the primary tumor can metastasize via the lymph system.