Biosci E109 Final Questions With Complete Solutions
explain a pacemaker potential of cardiac autorhythmic cells
Correct Answers funny ion channels open when the resting
potential is reached and releases Na+ into the cell while letting
some K+ out. This causes a slight depolarization. The funny ion
channels then close once a certain potential is reached. Ca2+
channels open and cause rapid depolarization. Ca2+ channels
then close and K+ channels open letting K+ out of the cell. Once
resting potential is reached, it immediately repeats
explain excitation contraction coupling in cardiac muscle cells
Correct Answers action potential enters adjacent cell. This
causes Ca2+ channels to open and Ca2+ enters. Ca2+ cause
ryanodine channels to release more Ca2+. Ca2+ spark occurs
and generate a Ca2+ signal. Ca2+ binds to troponin which
causes contraction
explain the depolarization of an action potential Correct
Answers once a threshold is reached, Na+ channels open
allowing Na+ to enter the cell which makes the cell more
positive
explain the hyper polarization in an action potential Correct
Answers K+ channels close but K+ continues to leak out of the
cell making the cell even more negative
explain the repolarization of an action potential Correct
Answers Na+ channels close and K+ channels open allowing
the K+ channels to leave the cell and become more negative
explain a pacemaker potential of cardiac autorhythmic cells
Correct Answers funny ion channels open when the resting
potential is reached and releases Na+ into the cell while letting
some K+ out. This causes a slight depolarization. The funny ion
channels then close once a certain potential is reached. Ca2+
channels open and cause rapid depolarization. Ca2+ channels
then close and K+ channels open letting K+ out of the cell. Once
resting potential is reached, it immediately repeats
explain excitation contraction coupling in cardiac muscle cells
Correct Answers action potential enters adjacent cell. This
causes Ca2+ channels to open and Ca2+ enters. Ca2+ cause
ryanodine channels to release more Ca2+. Ca2+ spark occurs
and generate a Ca2+ signal. Ca2+ binds to troponin which
causes contraction
explain the depolarization of an action potential Correct
Answers once a threshold is reached, Na+ channels open
allowing Na+ to enter the cell which makes the cell more
positive
explain the hyper polarization in an action potential Correct
Answers K+ channels close but K+ continues to leak out of the
cell making the cell even more negative
explain the repolarization of an action potential Correct
Answers Na+ channels close and K+ channels open allowing
the K+ channels to leave the cell and become more negative
