Quiz 2

: In the context of cardiac muscle contraction, what is the significance of the Frank-Starling Law?

• It regulates the refractory period

• It controls the action potential duration

• It determines the force of contraction based on initial muscle length

• t governs the conduction velocity in the heart

What are the two main types of tissues found in the heart?

• Endocardial and epicardial cells

• Myocardial or contractile cells and cells of the conducting system

• Atrial and ventricular cells

• Cardiomyocytes and fibroblasts

What is the primary pacemaker of the heart?

• Atrioventricular (AV) Node

• Bundle of His

• Sinoatrial (SA) Node

• Purkinje fibers

What is the physiological property responsible for the regular generation of action potentials in the heart?

• Length Tension Relationship

• Spontaneous Rhythmicity

• Prolonged Repolarization

• Autorhythmicity

What is the purpose of the delay in transmission of the cardiac impulse in the Atrioventricular (AV) Node?

• To increase heart rate

• To allow time for atrial contraction

• To allow time for the atria to empty their blood into the ventricles

• To synchronize ventricular contraction

What is the Frank-Starling Law, and how does it relate to cardiac output?

• It determines the heart's conductivity

• It regulates the heart's refractory period

• It states that the force of contraction is proportional to the initial length of the cardiac muscle fiber

• It controls the heart rate

What is the role of the Purkinje fibers in the heart's conduction system?

• Generate action potentials

• Distribute electrical excitation to the ventricles

• Act as the primary pacemaker

• Regulate heart rate

Explain the mechanism behind the prolonged action potential in cardiac myocytes.

• Increased potassium permeability

• Rapid sodium influx

• Voltage-gated slow calcium channels causing a plateau

• Decreased calcium concentration

How does the refractory period in cardiac muscle contribute to the continuous pumping action of the heart?

• It allows for wave summation

• It prevents tetany

• It facilitates early repolarization

• It increases heart rate

Describe the consequences of an AV block on the heart's function.

• Increased heart rate

• Decreased cardiac output

• Enhanced ventricular contraction

• Improved blood pumping efficiency