Lariat formation is characterize by 2’-5’ phosphodiester bond Prp8, a large scaffold protein that directly contacts both the 5’ and 3’ splice sites within the spliceosome.

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#Unit 7. System Physiology – Animal

In cardiac muscle, the action potential is caused by opening of three types of channels

Voltage activated fast sodium channels 

L-type calcium channels (slow calcium channels or calcium-sodium channels)

Voltage activated potassium ion channels

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#Unit 7. System Physiology – Animal

Phase 0 (depolarization), fast sodium channels open. 

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#Unit 7. System Physiology – Animal

Phase 1 (initial repolarization), fast sodium channels close

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#Unit 7. System Physiology – Animal

Phase 2 (plateau), calcium channels open and fast potassium channels close.

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#Unit 7. System Physiology – Animal

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

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#Id: 3996

#Unit 7. System Physiology – Animal

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