30 Questions
Which of the following types of muscle fibers are responsible for conducting the impulse to the heart?
Nodal muscle fibers
Where are the Nodal muscle fibers located in the heart?
Sinoatrial node (SAN) and Atrioventricular node (AVN)
What is the function of the Atrioventricular node (AVN)?
Conducts the impulse to the heart
What is the main function of the atrial muscles?
Act as blood reservoirs during ventricular systole
Where do the Specialized conducting fibers connect in the heart?
Atrial and ventricular muscles sheets
What is the region where the cardiac impulse arises known as?
Pacemaker of the heart
How are the ventricular muscle fibers arranged?
In a spiral manner from base to apex in 3 layers
Which valve separates the right atrium from the right ventricle?
Tricuspid valve
Which part of the heart has Conducting muscle fibers located in it?
Atrial and ventricular wall
What is the function of cardiac valves?
To allow passage of blood only in one direction
Which structure is important in the regulation of arterial blood pressure?
Atrial muscles
What is the main characteristic of atrioventricular valves?
They separate atria from ventricles
What is the function of the mitral valve?
Prevents eversion of the AV valves into atria during systole
Which component is responsible for the regular beating of the heart?
Rhythmicity
What is the role of cordae tendinae in relation to the mitral valve?
Prevent eversion of AV valves into ventricles
Which component of cardiac muscle converts potential energy into mechanical energy?
Contractility
What is the origin of heart rhythm according to the text?
Myogenic
'Pacemaker of the heart' refers to which component mentioned in the text?
SAN
What is the main cause of the diastolic depolarization during atrial diastole in the SAN action potential?
Na+ influx through funny (slow) Na+ channels
Which ion is responsible for the upstroke phase (phase 0) of the SAN action potential?
Ca++ through L (long-lasting) Ca++ channels
What triggers the repolarization phase (phase 3) in the SAN action potential?
K+ efflux through potassium channels
What is the role of calcium ions in the SAN action potential?
Cause the upstroke phase via L-type calcium channels
Which channel is responsible for the gradual rise in membrane potential during atrial diastole in the SAN action potential?
Funny (slow) Na+ channels
What is the resting membrane potential of contractile cardiac muscle fibers?
-85 mV
What is the main cause of the rapid depolarization in Phase 0 of the action potential of contractile cardiac muscle fibers?
Opening of fast Na+ channels leading to rapid Na+ influx
What characterizes Phase 2 of the action potential in contractile cardiac muscle fibers?
Slow prolonged repolarization
Which ion plays a crucial role in the slow prolonged repolarization phase (plateau) of the action potential in cardiac muscle fibers?
Ca++
What happens during Phase 3 of the action potential in contractile cardiac muscle fibers?
Marked increase in K+ efflux causing rapid repolarization
During which phase does the membrane potential return to its resting level in the action potential of contractile cardiac muscle fibers?
Phase 4
What is the duration of depolarization in Phase 2 for atrial muscles compared to ventricular muscles?
0.30 seconds in atrial muscles and 0.15 seconds in ventricular muscles
Learn about the properties of cardiac muscle including rhythmicity, excitability, and conductivity. Explore the structure and function of the mitral valve which connects the left atrium with the left ventricle. Understand the roles of cordae tendinae and papillary muscles in preventing the eversion of AV valves.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
