GAI and RGA proteins normally act as repressors of gibberellin responses. Gibberellin acts indirectly through an unidentified signaling intermediate, which is thought to bind to the regulatory domains of the GAI and RGA Proteins. 

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#Id: 5275

#Unit 7. System Physiology – Animal

L-type calcium channels become inactivated (i.e., they close) within about 100 to 150 milliseconds after opening

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#Id: 5276

#Unit 7. System Physiology – Animal

When the L-type calcium channels become inactivated at about the same time, greatly increased numbers of potassium channels open.

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#Id: 5277

#Unit 7. System Physiology – Animal

Large quantities of positive potassium ions diffuse out of the SA node.

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#Id: 5278

#Unit 7. System Physiology – Animal

Potassium channels remain open for another few tenths of a second, with resultant excess negativity inside the fiber; this process is called hyperpolarization.

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#Id: 5279

#Unit 7. System Physiology – Animal

TLS Online TPP Program

#Id: 5280

#Unit 7. System Physiology – Animal

The effects of the autonomic nervous system on heart rate are called  chronotropic effects.