TLS Online TPP Program

#Id: 4012

#Unit 7. System Physiology – Animal

The inherent leakiness of the sinus nodal fibers to sodium and calcium ions causes their self-excitation.

TLS Online TPP Program

#Id: 4013

#Unit 7. System Physiology – Animal

SA node has Prepotential or pacemaker potential which is the gradual potential rise from the resting membrane potential to threshold  ( -40 mV) & this occur spontaneously

TLS Online TPP Program

#Id: 4014

#Unit 7. System Physiology – Animal

Membrane ion channels that play important roles in generation of the action potential:

T (transient) channels 

L (long-lasting) channels Voltage gated potassium ion channel

TLS Online TPP Program

#Id: 4015

#Unit 7. System Physiology – Animal

Between heartbeats, influx of positively charged sodium ions causes a slow rise in the resting membrane potential in the positive direction. 

TLS Online TPP Program

#Id: 4018

#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: 4019

#Unit 7. System Physiology – Animal

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