A ________ sheath surrounds and insulates some axons and increases their conduction speed.
Fill in the blank(s) with the appropriate word(s).
myelin
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A mixed nerve is one that contains both
A. cranial and spinal nerve fibers. B. sensory and motor neurons. C. unipolar and bipolar neurons. D. an endoneurium and an epineurium. E. presynaptic and postsynaptic neurons.
Which of the following is incorrect pertaining to the pericardium?
A) It consists of visceral and parietal layers of serous pericardium, and the fibrous pericardium. B) The visceral and parietal layers of the serous pericardium are continuous around the aorta and pulmonary trunk where they exit the heart. C) It is mainly supplied with blood from the pericardiophrenic artery. D) It has pain fibers that are conveyed by the intercostal nerves. E) It encloses the terminal part of the inferior vena cava.
Once fertilization has occurred, the activities of development begin. The first such activity is ________
A) the formation of organ systems B) cellular specialization C) an increase in cell number
Stimulation of the aortic baroreceptors reflexively results in
A) stimulation of the cardioaccelerator center in the brain. B) increased sympathetic stimulation of the heart. C) increased activity by the parasympathetic nervous system. D) stimulation of the vasoconstrictive center. E) increased heart rate.