Siamois and Twin interact in the organizer with the Smad2 transcription factor activated by vegetal TGF-β family members (Nodal-related proteins, Vg1, activin)

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#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.