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85 Cards in this Set
- Front
- Back
What's the main function of the lymphatic system?
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To collect and transport tissue fluids from the intercellular spaces in all the tissues of the body back to the veins in the blood system.
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The lymphatic system plays a vital role in returning what kind of proteins to the bloodstream?
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Plasma proteins
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What are the six main functions of the lymphatic system? Try this mnemonic device involving a british stripper -- For Five Pounds Lola Dances Twice
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1) Fluids -- transportation of tissue fluids from intercellular spaces to veins
2) Fats -- transportation of digested fats from villi in small intestine through lacteals and lymph vessels to blood strem 3) Plasma -- returning plasma proteins to the bloodstream 4) Lymphocytes -- creation of lymphocytes 4) Defense -- defending against invading microorganisms and disease by removing and destroying them 6) Transportation -- moving large molecular compounds from their manufactured sites to the bloodstream |
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The name of the dilated sac at the base of the thoracic duct is the ____ ____.
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Cisterna chyli
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Define "lymphatic vessel."
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A one-way system in which lymph flows toward the heart
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What are four types of lymph vessels?
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1) Capillaries (microscopic, permeable, blind-ended)
2) Lymphatic collecting vessels 3) Ducts 4) Trunks |
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What are three main characteristics that differentiate lymphatic capillaries from blood capillaries?
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1) They're remarkably permeable
2) They have loosely joined endothelial minivalves 3) They withstand interstitial pressure and remain open |
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What do minivalves allow to enter lymph capillaries?
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Interstitial fluid
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What don't minivalves allow to escape from lymph capillaries?
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lymph
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What three things can lymph capillaries absorb during inflammation?
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1) Cell debris
2) Pathogens 3) Cancer cells |
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What are lacteals?
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Specialized lymph capillaries found in intestinal mucosa that absorb digested fat and deliver chyle to the blood
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What are lymphatic trunks?
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Large lymphatic vessels formed by the union of the largest collecting ducts
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What are the major lymphatic trunks?
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Paired trunks:
1) Lumbar trunks 2) Bronchomediastinal trunks 3) Subclavian trunks 4) Jugular trunks Single trunks: 1) Intestinal trunk |
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What are the two large lymphatic ducts called?
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The right lymphatic duct and the thoracic duct
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What areas of the body does the right lymphatic duct serve?
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1) Right arm
2) Right side of head and neck 3) Right thoracic region |
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To what vein does the right lymphatic duct deliver lymph?
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Right subclavian vein
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What areas of the body does the thoracic duct serve?
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1) Lower extremities
2) Abdomen 3) Left arm 4) Left side of head and neck 5) Left thoracic region |
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To what vein does the thoracic duct deliver lymph?
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Left subclavian vein
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Does the lymphatic system have any sort of organ that serves as a pump?
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No
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What methods do lymph vessels use to propel lymph?
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The same as veins -- muscular pumping, respiratory pumping.
Also, pulsations of nearby arteries promote lymph flow. Finally, contractions of smooth muscle in lymphatic trunks propel lymph. |
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Lymph vessels are usually packaged with what?
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With blood vessels in connective tissue sheaths
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How much lymph enters the bloodstream each day?
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About 3L
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What are the main cells involved in the immune response?
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Lymphocytes
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What are the two main varieties of lymphocytes?
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T cells and B cells
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Against what do T and B cells protect us?
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Antigens -- these include bateria and their toxins, viruses, mismatched RBCs and cancer cells
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What do T cells do?
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Manage the immune response and attack and destroy foreign cells
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What do B cells do?
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Produce plasma cells which secrete antibodies
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What do antibodies do?
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Immobilize antigens
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Besides lymphocytes, what are the main lymphoid cells?
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1) Macrophages
2) Dendritic cells 3) Reticular cells |
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What do macrophages do?
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Phagocytize foreign substances and help activate T cells
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What are dendritic cells?
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Spiny-looking cells that function similarly to macrophages
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What are reticular cells?
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Fibroblast-like cells that produce a stroma, which is a network that supports other lymphoid cells in lymphoid organs
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What are the two types of lymphoid tissue?
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Reticular connective tissue and diffuse lymphatic tissue
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What is reticular connective tissue?
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Solid, spherical bodies consisting of tightly packed reticular elements and cells
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Does a lymphatic follicle (nodule) consist of reticular connective tissue or diffuse lymphatic tissue?
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reticular connective tissue
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What's diffuse lymphatic tissue?
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Scattered reticular tissue elements in every body organ
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What are the principle lymph organs?
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Lymph nodes
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Where are aggregations of lymph nodes found?
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Along lymphatic vessels near the surface in the inguinal, axillary, and cervical regions of the body
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What are the two main functions of lymph nodes?
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1) Filtration, in which macrophages destroy microorganisms and debris
2) Immune system activation, or monitoring for antigens and mounting attacks against them |
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What are the two histologically distinct regions of a lymph node?
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Cortex and medulla
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What extends inward from a lymph node's capsule, dividing it into compartments?
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Trabeculae
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What's a brief physical description of lymph nodes?
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Bean shaped, surrounded by a fibrous capsule
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What does a lymph node cortex contain?
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Follicles with germinal centers, heavy with dividing B cells
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What type of cells practically encapsulate lymph node follicles?
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Dendritic cells
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What does the deep cortex of a lymph node contain?
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T cells in transit
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When are T cells present in blood, lymph nodes, and the lymphatic stream?
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Always
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____ ____ extend from the cortex and contain B cells, T cells, and Plasma cells.
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Medullary cords
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Throughout a lymph node you will find ____ _____ crisscrossed by reticular fibers.
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lymph sinuses
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Where do macrophages reside?
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On reticular fibers in lymph sinuses
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Besides lymph nodes, what lymphoid organs do we have?
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Spleen, thymus gland, tonsils
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Where else do we find lymphoid tissue?
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Scattered in connective tissue and in Peyer's patches in the intestines
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What organs filter lymph?
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Lymph nodes
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What's the largest lymphoid organ?
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The spleen
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Where is the spleen located?
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On the left side of the abdominal cavity beneath the diaphragm, extending to curl around the anterior aspect of the stomach.
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What blood vessels serve the spleen?
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Splenic artery and vein
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What are the spleen's three main functions?
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1) Proliferation of lymphocytes
2) Immune surveillance and response 3) Cleansing of blood |
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What are the secondary functions of the spleen?
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Breakdown of RBC products for later use, salvaging and storing iron for later use in bone marrow, production of fetal erythrocytes, blood platelet storage
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Briefly describe the structure of the spleen
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Surrounded by a fibrous capsule, it has trabeculae that extend inward and it contains lymphocytes, macrophages, and huge numbers of erythrocytes
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What are the two distinct sections of the spleen?
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Red pulp and white pulp
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Describe white pulp of the spleen
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An area containing mostly lymphocytes suspended in reticular fibers and involved in immune functions
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Describe red pulp of the spleen
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Splenic tissue concerned with disposal of worn-out RBCs and bloodborne pathogens
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Where do you find most white pulp in the spleen?
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Clustered around arteries
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What's the thymus gland?
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A bilobed organ that secretes hormones (thymosin and thymopoietin) that cause T lymphocytes to become immunocompetent
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define "immunocompetent."
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Possessing the capacity for a normal immune response
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With what does the size of the thymus gland vary?
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age
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When is the thymus gland most active?
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Childhood
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Where is the thymus gland found in infants?
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In the inferior neck extending into the mediastinum where it partially overlies the heart
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What happens to the thymus gland during adolescence?
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It stops growing and begins to atrophy through adulthood
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What are the two portions of a thymic lobe?
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Outer cortex, inner medulla
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What does the outer cortex of a thymic lobe contain?
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Densely packed lymphocytes and scattered macrophages
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What does the inner medulla of a thymic lobe contain?
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A few lymphocytes and thymic (Hassal's) corpuscles
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What two characteristics make the thymus gland different from other lymphoid organs?
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1) It functions strictly in T cell maturation
2) it does not directly fight antigens |
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Of what does the stroma of the thymus consist?
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Star-shaped epithelial cells (not reticular fibers)
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What do the star-shaped endothelial cells found in the stroma of the thymus gland do?
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Secrete hormones that stimulate lymphocytes to become immunocompetent
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What are the simplest lymphoid organs?
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Tonsils
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What are the four groups of tonsils called?
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1) Palatine tonsils
2) Pharyngeal tonsils 3) Lingual tonsils 4) Tubal tonsils |
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Where are the palatine tonsils found?
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Either side of the posterior end of the oral cavity
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Where are lingual tonsils found?
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The base of the tongue
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Where is the pharyngeal tonsil found?
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Posterior wall of the nasopharynx
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Where are the tubal tonsils found?
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Surrounding the openings of the auditory tubes into the pharynx
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What do tonsils do?
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Tonsils trap and destroy bacteria and particulate matter in their crypts
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What do tonsils consist of?
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Follicles with germinal centers
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What are the functions of Peyer's patches and the appendix?
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1) Destroying bacteria and preventing them from breaching the intestinal wall
2) Generating memory lymphocytes for long-term immunity |
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What is MALT?
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Mucosa-associated lymph tissue
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What does MALT consist of?
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Peyer's patches, tonsils, appendix, and the walls of bronchi in the respiratory tract
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