ActionpotentialsSlow waveThreshold60- Intensity: 5~15 mVSlowwavesTime (sec)-Frequency:3~12 cpm(cpm: counts per minute)()-lonicmechanism(next page)Time (sec)2011Pearson Education,Inc
– Intensity: 5 ~ 15 mV – Frequency: 3 ~ 12 cpm (cpm: counts per minute) Slow wave – Ionic mechanism (next page)
.lonic Mechanisms- BER might be due to spontaneous rhythmicchanges in Na+-K+ pump activity, Ca2+Actionpotentials Ouabain (Na+-K+pump)Threshold→BERdisappear60SlowwavesTime (sec)notgeneratedbyneural)system.Time (sec)@2011 Pearson Education, Inc
– BER might be due to spontaneous rhythmic changes in Na+ -K+ pump activity, Ca2+ • Ionic Mechanisms – Ouabain (Na+ -K+ pump) → BER disappear – not generated by neural system
Frequencies:3-12 counts/minuteActionpotentialscpmThreshold-12cpmA60SlowwavesTime (sec)10.8cpmProximal jejunum()s9.6 cpmDistal jejunum8cpmDistalileumProximalileumTime (sec)2011 Pearson Education, Inc
Frequencies: 3-12 counts/minute
(c) Spike potentialss(actionpotentials)ActionpotentialsOnly at the peaks ofslow waves.Threshold.Threshold: - 40 mV60Slowwaves-Duration:10~20msTime (sec)- lonic mechanism:()· Depolarization: Ca2+ influx·Repolarization: K+ effluxTime (sec)@2011PearsonEducation,Inc
• Only at the peaks of slow waves. (c) Spike potentials (action potentials) • Threshold: – 40 mV – Ionic mechanism: • Depolarization: Ca2+ influx • Repolarization: K+ efflux – Duration: 10~20 ms
· Spikes are Aps, caused by the influx of primarily Ca2+andsomeNat. They occur once the resting membrane potentialdepolarizes to about 4OmV.: The more depolarized the resting membrane potentialbecomes during the slow waves, the greater the frequency ofspikes.. The Ca2+ that enters the muscle during the spike causesthecontraction
• Spikes are Aps, caused by the influx of primarily Ca2+ and some Na+ . • They occur once the resting membrane potential depolarizes to about 40mV. • The more depolarized the resting membrane potential becomes during the slow waves, the greater the frequency of spikes. • The Ca2+ that enters the muscle during the spike causes the contraction