Only asparagine residues in the tripeptide sequences Asn-X-Ser and Asn-X-Thr (where X is any amino acid except proline) are substrates for oligosaccharyl transferase.

TLS Online TPP Program

#Id: 3994

#Unit 7. System Physiology – Animal

Phase 3 (rapid repolarization), calcium channels close and slow potassium channels open

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.

TLS Online TPP Program

#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.