The SA node is the heart's normal pacemaker because
a. it has the fastest rate of autorhythmicity
b. it has both sympathetic and parasympathetic innervation
c. it lies in the right atrium
d. activation of K+ channels occurs more rapidly in this region than elsewhere in the heart
e. it can directly stimulate atrial and ventricular cardiac myocardial contractile cells
A
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Feedforward regulatory processes
A. work in anticipation of changes in regulated variables. B. are identical to positive feedback processes C. lead to instability of the regulated variable D. maximize fluctuations in the regulated variable E. tend to force physiological variables away from their set point.
Which of the following conditions would be associated with hypernatremia?
A) increased plasma sodium B) decreased plasma volume C) decreased plasma osmolarity D) increased plasma potassium E) hypotension
Sound travels directly to the eardrum through the
A) pinna. B) external auditory canal. C) cochlea. D) vestibule. E) ear ossicles.
In which condition are the lungs infected with Mycobacterium and produce fibrous nodules around the bacteria, leading to progressive pulmonary fibrosis?
A. Pneumonia B. Dyspnea C. Pneumothorax D. Rhinitis E. Tuberculosis