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WorksheetsCardiac Muscle and Electrical Activity
Total questions: 18
Worksheet time: 9mins
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
What is the purpose of the Purkinje fibers in the heart?
Supply the right papillary muscles
Conduct the impulse to the atria
Initiate the action potential
Spread the impulse to the ventricular muscle cells
Which ions play a critical role in the action potentials of cardiac cells?
Potassium (K+)
Chloride (Cl-)
Sodium (Na+)
Calcium (Ca2+)
What is the role of calcium ions in cardiac conductive cells?
Depolarize the cell
Repolarize the cell
Slowly increase the membrane potential
Initiate the action potential
This tool is used to measure the electrical activity of the heart
ECG
AED
CPAP
MRI
What does the P wave represent on an ECG tracing?
What does the QRS complex represent on an ECG tracing?
What does the T wave represent on an ECG tracing?
An interruption in the normal electrical conduction pathway in the heart is referred to as a:
heart block
myocardial infarction
pulmonary embolism
fibrillation
