A more attractive alternative is to cover the reaction mixture with a plug of inert wax and place the critical reagent on top of this plug. 

TLS Online TPP Program

#Id: 3996

#Unit 7. System Physiology – Animal

Phase 4 (resting membrane potential) averages about −90 millivolts.

TLS Online TPP Program

#Id: 4001

#Unit 7. System Physiology – Animal

TLS Online TPP Program

#Id: 4006

#Unit 7. System Physiology – Animal

The SA node exhibits automaticity; it can spontaneously generate action potentials without neural input.

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#Id: 4008

#Unit 7. System Physiology – Animal

SA node has an unstable resting membrane potential. The “resting membrane potential” of the sinus nodal fiber between discharges has a negativity of about −55 to −60 millivolts.

TLS Online TPP Program

#Id: 4010

#Unit 7. System Physiology – Animal

The cause of less negative RMP of SA node is that the cell membranes of the sinus fibers are naturally leaky to sodium and calcium ions.

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.