What is the function of the tunica externa?
A. Anchors the vessel to surrounding tissue
B. Secretes a chemical to repel platelets so blood can easily flow through the vessel
C. Contracts to move the blood through the vessel
D. None of these are correct.
Answer: A
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Sweat and sebaceous glands develop from the
A. reticular layer. B. hypodermis. C. stratum basale of the epidermis. D. stratum corneum. E. papillary layer of the dermis.
Hypercapnia and acidosis have positive chronotropic effects.
Answer the following statement true (T) or false (F)
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.
Helpful, nonharmful bacteria live in
A. the urinary bladder. B. the mouth. C. the intestine. D. both intestine and mouth.