BIOM 3200 Chapter 2: W2-Text-Notes.docx
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Stimulus intensity: because aps are all or none, a greater stimulus will not produce greater amplitude of reaction, but will cause aps to fire more frequently (very fast). Because of the absolute refractory period however, another ap will not begin until the other has finished, even if another stimulus is delivered immediately after the first (multiple pin pricks in the same spot will cause one feeling). During the relative refractory period, the k+ channels have just opened, and if any na+ channels are still open, a strong enough stimulus can depolzarize the cell from a hyperpolarized state. Week two unit two self study quiz: differentiate between a chemical and electrical synapse. Electrical synapse: are formed directly between cell via channel proteins (connexins) which form a pore through which ions can pass through. They allow rapid syncytial contraction for the heart and peristalsis. They may also function in the brain neuroglial cells and the eyes.