Diphenyltetrazolium bromide, a yellow tetrazole is reduced by metabolically active cells to form insoluble, purple formazan dye crystals detected at 570nm

TLS Online TPP Program

#Id: 5438

#Unit 7. System Physiology – Animal

Voltage-gated sodium channel has two gates:

activation gate near the outside of the channel 

Inactivation gate near 

the inside of the channel 

TLS Online TPP Program

#Id: 5439

#Unit 7. System Physiology – Animal

During overshoot  

the direction of the electrical gradient for Na+ is reversed because the membrane potential is reversed & this limits Na + influx 

TLS Online TPP Program

#Id: 5440

#Unit 7. System Physiology – Animal

During overshoot 

the voltage-gated K+  channels open & contribute to repolarization

TLS Online TPP Program

#Id: 5441

#Unit 7. System Physiology – Animal

The opening of voltage-gated K+ channels is slower and more prolonged than the opening of the Na + channels, and much of the increase in K + conductance comes after the increase in Na+ conductance

TLS Online TPP Program

#Id: 5442

#Unit 7. System Physiology – Animal

voltage-gated K + channels bring the action potential to an end and cause closure of their gates through a negative feedback process

TLS Online TPP Program

#Id: 5443

#Unit 7. System Physiology – Animal

The net movement of positive charge out of the cell due to K+ efflux at this time helps complete the process of repolarization

Relative refractory period