An autorhythmic heart cell is one in which
A. action potentials always occur at exactly the same frequency.
B. action potentials are stimulated by internal stores of acetylcholine.
C. action potentials fire spontaneously.
D. action potentials are initiated by the autonomic nervous system.
E. all filaments contract and relax with a high degree of synchrony.
Answer: C
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If someone speaks too loudly into a microphone, a public address system will sometimes produce a loud whistle of amplified feedback
Explain whether this is an example of negative or positive feedback, and explain how the microphone, control box, and speaker of the system serve as the different components of a feedback loop.
Which of the following is FALSE concerning glucose transport across the proximal tubule?
A) Glucose transport requires energy. B) Glucose moves by paracellular transport. C) Glucose is passively transported across the basolateral membrane by facilitated diffusion. D) Glucose is normally 100% reabsorbed. E) Glucose is actively transported across the apical membrane by cotransport with sodium.
A bundle of fibers inside the central nervous system is called a ____
a. ganglion b. tract c. nucleus d. soma
The lowermost portion of the pharynx is called the ____________________
Fill in the blank(s) with correct word