Cardiac Muscle and Electrical Activity

What is the unique property of cardiac muscle that allows it to initiate an electrical potential at a fixed rate?

• Autorhythmicity

• Contractility

• Excitability

• Elasticity

Which type of cardiac muscle cells conduct impulses and are responsible for contractions that pump blood through the body?

• Sinoatrial (SA) node

• Myocardial contractile cells

• Myocardial conducting cells

• Purkinje cells

What is the function of myocardial conducting cells in the heart?

• Provide energy for contractions

• Bind cardiac muscle cells together

• Store calcium ions for contraction

• Initiate and propagate the action potential

What is the structure that allows the electrical impulse to reach the interior of cardiac muscle cells?

• T tubules

• Sarcoplasmic reticulum

• Intercalated discs

• Myofibrils

What is the purpose of intercalated discs in cardiac muscle cells?

• Store lipids and glycogen

• Provide energy for contractions

• Allow the passage of ions between cells

• Support synchronized contraction of the muscle

True or false: Following a heart attack, damaged cardiac muscle cells are easily repaired or replaced.

• true

• false

Which clump of myocardial conducting cells is known as the pacemaker of the heart?

• Atrioventricular (AV) node

• Sinoatrial (SA) node

• Purkinje fibers

• Atrioventricular bundle

What is the purpose of the atrioventricular (AV) node in the heart?

• Initiate the action potential

• Supply the left ventricle with oxygen

• Conduct the impulse back to the atria

• Delay the electrical impulse, allowing atrial contraction to complete before the onset of ventricular contraction

What is the typical maximum heart rate in a healthy young individual?

• 160 per minute

• 120 per minute

• 180 per minute

• 220 per minute

Which structure divides into the left and right bundle branches in the heart?

• Atrioventricular bundle (Bundle of His)

• Sinoatrial (SA) node

• Atrioventricular (AV) node

• Purkinje fibers