Which of the following statements regarding the lymphoid organs is NOT true?
A. The primary lymphoid organs are the bone marrow and thymus.
B. The thymus secretes protein hormones, collectively called thymopoietins.
C. Large numbers of macrophages and lymphocytes are found in the lymph nodes and spleen.
D. The tonsils contain lymphocytes, macrophages, and dendritic cells that respond to microbes in food.
E. Once a lymphocyte reaches a secondary lymphoid organ, it remains there for its lifetime.
E
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The folds of the surface of the cerebellum
A) are called folia and are less prominent than the cerebral folds. B) form a network of blood vessels over the brain. C) consist of axons and dendrites of neurons. D) are bathed in spinal fluid. E) are called sulci.
The most rapid conduction of an impulse along an axon occurs on a fiber that is
A) thick and myelinated. B) thin and unmyelinated. C) thick and unmyelinated. D) thin and myelinated.
The head is ____ to the heart
a. superior b. distal c. deep d. inferior
The right border of the heart is supplied by the
A. circumflex artery. B. anterior interventricular artery. C. posterior interventricular artery. D. right marginal artery. E. great cardiac vein.