Electrical Activity Of Heart Part 2 Flashcards
What ion channel is spontaneously opened to initiate prepotentials in pacemaker cells?
Na+
What ion channel opens to cause cardiac muscle contraction?
Ca2+
What is released when muscle relax?
K+
What is the result of 3 Na+ out of cell & 2 K+ into cell for cardiac muscles?
Resting membrane potential
During phase 0, what ion channel is opened to cause rapid depolarization?
Voltage gated Na+
During phase 1, ___ channels inactivate, which causes the Na+ permeability to decrease quickly
Na+
During phase 1, what doe the inactivation of Na+ channels result in?
Repolarization
During phase 2, what ion gate closes so that its permeability decreases?
K+
In phase 2, the Ca2+ channels open, which causes permeability to =
Increase
In phase 3 and 4, the __ channels reopen, and the ___ channels close
K+
Ca2+
What are specialized gap junctions allow ionic currents created by an action potential in one cell to flow into the neighboring cells?
Functional syncytium
_______ muscle cells for a functional syncytium
Cardiac
__________ muscles are electrically isolated from one another
Skeletal
Cardiac action potential has a ______ refractory period
Long
Skeletal action potential has a _______ refractory period
Small
