21) Masses of lymphoid tissue within a lymph node.
A) trabeculae
B) hilum
C) lymphoid follicles
D) white pulp
E) subcapsular sinus
22) The lymphoid organ that atrophies with age.
A) thymus
B) tonsils
C) aggregated lymphoid nodules
D) lymph nodes
E) spleen
23) Duct of the lymphatic system that drains the body's entire lower half.
A) lumbar trunk
B) intestinal trunk
C) bronchomediastinal trunk
D) thoracic duct
E) right lymphatic duct
24) Lymphoid tissue associated with the digestive, respiratory, urinary, and reproductive tracts.
A) aggregated lymphoid nodules
B) tonsils
C) MALT
D) lacteals
E) crypts
25) Blind-end invaginations of tonsil epithelium that trap bacteria and particulate matter.
A) aggregated lymphoid nodules
B) tonsils
C) MALT
D) lacteals
E) crypts
26) Which of these statements regarding lymph capillaries is
false?
A) They begin as closed-ended tubes.
B) They have precapillary sphincters that regulate drainage of lymph from tissues.
C) They lack barriers to stop cancer cells from entering the lymphatic system.
D) They unite with each other to form collecting vessels.
27) The sinuses within lymph nodes
A) are separated from the bloodstream by a blood-node barrier.
B) consist of star-shaped epithelial cells that secrete immune-boosting hormones.
C) contain macrophages living along a reticular fiber network.
D) surround clumps of lymphoid tissue called white pulp.
28) Given that a germinal center arises from a single activated lymphocyte, how many different kinds of antibodies are secreted by a single germinal center (and by the plasma cells it produces)?
A) none; T cells do not produce antibodies
B) one
C) several dozen
D) thousands
29) The largest kind of lymphatic vessel is a lymphatic
A) duct.
B) trunk.
C) sinus.
D) capillary.
30) Lymphatic capillaries are present in
A) skin.
B) teeth.
C) the central nervous system.
D) bone marrow.