TLS Online TPP Program

#Id: 5274

#Unit 7. System Physiology – Animal

When the potential reaches a threshold voltage of about −40 millivolts, the L-type calcium channels become “activated,” causing the action potential.

TLS Online TPP Program

#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

TLS Online TPP Program

#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.

TLS Online TPP Program

#Id: 5277

#Unit 7. System Physiology – Animal

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

TLS Online TPP Program

#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.

TLS Online TPP Program

#Id: 5279

#Unit 7. System Physiology – Animal