Heart Wall Layers and Cardiac Muscle Function Quiz

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Which layer of the heart wall is responsible for the smooth inner surface of the heart?

Epicardium

Myocardium

Purkinje fibers

Endocardium (correct)

Which component of the cardiac conduction system is responsible for initiating the heart's rhythmic contractions?

Atrioventricular node

Atrioventricular bundle

Purkinje fibers

Sinoatrial node (correct)

What is the primary mechanism responsible for the generation of action potentials in cardiac muscle cells?

Spontaneous depolarization of the cell membrane

Contraction of the ventricular wall

Changes in membrane permeability to sodium and potassium ions (correct)

Stimulation from the sympathetic nervous system

How do the action potentials in cardiac muscle differ from those in skeletal muscle?

Cardiac muscle action potentials have a longer plateau phase Signup and view all the answers

What is the primary function of the atrioventricular (AV) node in the cardiac conduction system?

To coordinate the contraction of the atria and ventricles Signup and view all the answers

What is the role of the Purkinje fibers in the cardiac conduction system?

To distribute the action potentials to the ventricular myocardium Signup and view all the answers

Which of the following accurately describes the sequence of events during a cardiac cycle?

Atria contract first, followed by ventricles Signup and view all the answers

Which of the following statements about cardiac muscle cells is incorrect?

They use ATP for contractions, but not Ca2+ ions Signup and view all the answers

Which of the following structures is responsible for initiating the contraction of atrial muscle cells?

Sinoatrial (SA) node Signup and view all the answers

Which coronary artery supplies blood to the left ventricle?

Left coronary artery Signup and view all the answers

What is the function of intercalated disks in cardiac muscle cells?

Allow electrical impulses to propagate between cells Signup and view all the answers

Which of the following vessels drains blood from the cardiac muscle?

Cardiac veins Signup and view all the answers

Where does the action potential originate in the heart?

Sinoatrial node Signup and view all the answers

Which component of the heart's conduction system is responsible for slowly spreading action potentials?

Atrioventricular bundle Signup and view all the answers

Where are Purkinje fibers located in the heart?

In the left and right ventricles Signup and view all the answers

What function do Purkinje fibers serve in the heart's conduction system?

Rapidly deliver action potentials to ventricles Signup and view all the answers

Which part of the heart functions as the pacemaker due to a large number of Ca2+ channels?

Sinoatrial node Signup and view all the answers

What is responsible for recording electrical events in the heart and diagnosing cardiac abnormalities?

Electrocardiogram (ECG/EKG) Signup and view all the answers