Anatomy Exam 2 – Flashcards

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question
What is the main function of the lymphatic system?
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The lymphatic system returns leaked fluid and plasma proteins that escape from the bloodstream to the blood. Hydrostatic and osmotic pressures in capillary beds combine in such a way that some fluid is lost by capillaries that cannot be regained by them. These fluids return to venous circulation through the lymphatic system.
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Which of the following mechanisms is NOT used to propel lymph through lymphatic vessels? A. gravity B. small heart-like pumps C. the milking action of muscles D. pulmonary motion
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small heart-like pumps There is no direct pumping action in the lymphatic system. Movement of fluid depends on factors such as gravity and body movement.
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Which of the following promotes closure of the minivalves associated with lymph capillaries?
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increasing pressure inside the lymph capillary Minivalves will allow fluid in when external pressure exceeds internal pressure but will prevent fluid loss when the pressures are reversed.
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Which of the following is NOT a part of the lymphatic system? A. lymph nodes B. lymphatic vessels C. blood vessels D. lymph
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Blood vessels Blood vessels are not a part of the lymphatic system. They are a part of the circulatory system.
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Which lymphoid organ is primarily active during the early years of life?
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The thymus The thymus is responsible for the maturation of T lymphocytes, and while it is large in youth, it tends to be reduced in size as the body ages.
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Which lymphoid organ extracts aged and defective blood cells and platelets from the blood in addition to storing some of the breakdown products for later reuse?
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The spleen The spleen harbors macrophages that ingest and recycle materials from erythrocytes that have aged or become damaged.
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Which of the following is a role of lymph nodes?
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They filter lymph. Lymph nodes are rich with macrophages, B cells, and T cells; therefore, the lymph nodes are primed for activating the immune system. Structurally, lymph nodes have a capsule and medullary chords and sinuses that serve to filter lymph fluid.
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True or false? Lymph arrives at the lymph nodes via afferent lymphatic vessels.
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True. Afferent vessels deliver lymph to the lymph node. The lymph then filters through the subcapsular sinus of the node and then into a number of smaller sinuses that cut through the node's cortex and lead into the medulla. Eventually, lymph exits the node via the hilum and is carried away by efferent vessels.
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Which lymphoid organ(s) serve(s) in immune surveillance and blood cell recycling?
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The spleen The spleen is an important lymphoid organ in immune surveillance and has an important role in its red blood cell recycling.
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Which of the following lymph organs is NOT matched with its function? A. bone marrow: form lymphocytes B. Peyer's patches: mature B cells C. spleen: remove red blood cells D. thymus: mature T cells
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Peyer's patches: mature B cells Peyer's patches are lymphoid organs found in the wall of the distal portion of the small intestine.
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Of the following lymphoid organs, which is/are structurally simplest and lack(s) a complete capsule?
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tonsils Tonsils lack a complete capsule. The epithelium overlying tonsils invaginates deeply into their interior to form crypts where bacteria and particulate matter are trapped to be destroyed in the lymphoid tissue of the tonsils.
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Which of the following are primary lymphoid organs?
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bone marrow and thymus Yes, the B lymphocytes are named B cells because they mature in the Bone marrow and the T lymphocytes are named T cells because they mature in the Thymus. This is also where they become immunocompetent.
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Which of the following areas in a secondary lymphoid organ allows intimate contact between blood and the lymphocytes?
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white pulp of the spleen Yes, the white pulp is where lymphocytes are concentrated and the immune functions take place in the spleen.
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Where in the lymph node do the T cells first encounter antigens presented by dendritic cells?
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deep in the cortex Yes, the T cells encounter antigens presented by dendritic cells in the deeper part of the cortex. The cortex is the outer area of the lymph node.
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Collections of lymphoid tissues, called MALT, are strategically placed throughout the respiratory, digestive, and genitourinary systems. Which one of these is located at the end of the small intestine?
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Peter's patches Yes, Peyer's patches are located in the small intestine, and they guard against bacteria from the large intestine.
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There is a decrease in our ability to fight infection as we age. Which lymphoid organ may have a role in this decline?
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thymus Yes, the relative size of the thymus as well as its function decreases with age. Thymic atrophy may be one reason the elderly are more susceptible to infection.
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Which of the following provides a first line of defense against pathogens?
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intact skin and mucous membranes The first line of defense against disease is intact skin and mucous membranes. If an antigen (pathogen) cannot enter the body, a secondary defense is unnecessary.
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What type of immune system cell performs the most phagocytosis in the body?
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macrophages Macrophages, or "big eaters" perform most of the phagocytic activity in the body, ingesting bacteria, cellular debris, aging blood cells, and others.
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Four (or five) cardinal signs indicate inflammation. What specific sign of inflammation is the result of exudate in the tissue spaces?
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edema (swelling) Edema is caused when release of fluids from blood vessels exceeds their uptake. Not only is blood flow increased to inflamed areas, but capillaries are made more permeable to fluid, resulting in loss of fluid from the blood and tissue swelling.
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Which of the following is NOT a characteristic of Natural Killer (NK) cells?
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NK cells recognize abnormal or cancer cells by a specific antigen on their cell membrane. Correct answer. NK cells do not recognize abnormal or cancer cells by a specific antigen on their cell membrane. NK cells to do not have specific antigen receptors - like T cells do. NK cells look for the absence of normally occurring "self" proteins on infected or cancerous cells.
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Which of the following innate internal defenses work by interfering with viral replication?
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interferons Yes, interferons are antimicrobial proteins that interfere with viral replication. They are produced by a virus-infected cell. Although the infected cell will die, it sends out interferons that protect the neighboring cells from the virus.
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How do phagocytes recognize foreign cells or bacteria?
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The phagocytes recognize molecules on pathogens not normally found on body cells Yes, they use mannose and Toll-like receptors to bind to the molecules found on pathogens.
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Which of the innate defense mechanisms can lyse bacteria and mark cells for phagocytosis?
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complement proteins Yes, the complement proteins can lyse microorganisms using the MAC (membrane attack complex) system to form pores, mark cells for phagocytosis (opsonization), and promote inflammation.
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Which of the following can act as opsonins on bacteria, thus enhancing phagocytosis?
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antibodies and complement proteins Yes, both antibodies and complement proteins can act as opsonins on bacteria.
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The Lymphatic System
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System consisting of lymphatic vessels, lymph nodes, and lymph; drains excess tissue fluid from the extracellular space. The nodes provide sites for immune surveillance.
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MALT (Mucosa-Associated Lymphoid Tissue)
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Diffusely distributed collections of lymphoid tissue in mucous membranes.
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Adenoids
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Pharyngeal tonsil
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What is lymph? Where does it come from?
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Lymph is the fluid inside lymphatic vessels. It enters lymphatic vessels from interstitial fluid. Interstitial fluid, in turn, is a filtrate of blood plasma
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Name 2 lymphatic ducts and indicate the body regions usually drained by each.
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The right lymphatic duct receives lymph from the right upper arm and the right side of the head and thorax. The thoracic duct drains lymph from the rest of the body.
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What is the driving force for lymph movement?
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Lymph movement is driven by the contraction of adjacent skeletal muscles, pressure changes in the thorax during breathing, the pulsations of nearby arteries, and contraction of smooth muscle in the lymphatic vessel walls. (Valves in lymphatic vessels prevent backflow of lymph.)
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What is a lymphoid follicle? What type of lymphocyte predominates in follicles, especially in their germinal centers?
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Lymphoid follicles are solid, spherical bodies consisting of tightly packed reticular fibers and lymphoid cells, often with a lighter-staining central region. They are regions where B cells predominate.
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What is the benefit of having fewer efferent than afferent lymphatics in lymph nodes?
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Having fewer efferents causes lymph to accumulate in lymph nodes, allowing more time for its cleansing.
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List several functions of the spleen.
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The spleen cleanses the blood, recycles breakdown products of RBCs, stores iron, stores platelets and monocytes, and is thought to be a site of erythrocyte production in the fetus.
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What is MALT? List several components of MALT.
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MALT (mucosa-associated lymphoid tissue) is lymphoid tissue found in the mucosa of the digestive, respiratory, and genitourinary tracts. It includes tonsils, Peyer's patches, and the appendix.
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The sac that often forms the initial portion of the thoracic duct is the:
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cisterna chyli
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The structural framework of lymphoid organs is:
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reticular tissue
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The germinal centers in lymph nodes are largely sites of:
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proliferating B lymphocytes
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Lymphatic vessels _______.
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collect excess fluid from interstitial spaces
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Which of the following contribute(s) to the flow of lymph through lymphatic vessels?
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The milking action of skeletal muscle contraction Pressure changes in the thorax that result from breathing
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