Acetylcholine is excitatory at the neuromuscular junction, but inhibitory at the SA node. Explain why this is true.
What will be an ideal response?
Acetylcholine receptors in heart muscle are muscarinic, whereas they are nicotinic in skeletal muscle. These receptors are linked to different types of ion channels. At the nicotinic receptor, the response is excitatory due to a sodium influx. At the muscarinic receptor, the response is inhibitory due to a potassium efflux.
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A. A molecule that remains unchanged after assisting in a chemical reaction B. A molecule that helps to form the cytoskeleton of a cell C. A molecule that assists in the breakdown of proteins into amino acids in the stomach D. A molecule that breaks down sucrose into glucose and fructose
Which structure is supplied by postganglionic fibers originating in the ciliary ganglion?
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The P wave of an ECG indicates
A. atrial depolarization. B. atrial repolarization. C. ventricular depolarization. D. ventricular repolarization. E. threshold.