12 Questions
Which part of the cardiac muscle is responsible for storing and releasing calcium ions (Ca2+) for excitation-contraction coupling?
Sarcoplasmic reticulum (SR)
Where are T-tubules located in the cardiac muscle?
At the Z lines
What is the main component of the thick filaments in cardiac muscle?
Meromyosin/myosin
Which property of muscle cells allows them to respond to stimuli and initiate an action potential?
Irritability
What term refers to the ability of certain cells, like the sinoatrial node, to initiate their own electrical activity?
Automaticity
Which property of muscle cells enables them to generate force and shorten?
Contractility
Which type of cardiac cells exhibit slow response action potentials?
Purkinje fibers
Which phase of the cardiac action potential is characterized by rapid upstroke?
Phase 0
Where is the intrinsic pacemaker of the heart located?
Right atrium
During which phase of the cardiac action potential does potassium ion (K+) efflux cause early repolarization?
Phase 1
What is the primary ion responsible for the depolarization phase (phase 0) of the SA node action potential?
Sodium ions (Na+)
What causes the repolarization in phase 3 of the cardiac action potential?
Outward potassium ion (K+) current
Test your knowledge on T-tubules and the sarcoplasmic reticulum (SR) with this quiz. Learn about their functions and structures in cardiac cells, and discover their differences between the atria and ventricles.
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