Podcast
Questions and Answers
Why is the T wave more spread out and has a lower amplitude than the QRS complex?
Why is the T wave more spread out and has a lower amplitude than the QRS complex?
- Because atrial repolarization takes place during the period of ventricular excitation
- Because the time required for each ventricle to depolarize depends on its size relative to the other ventricle
- Because depolarization is faster than repolarization (correct)
- Because the paths of the depolarization waves through the ventricular walls change continuously
What is the purpose of the P wave?
What is the purpose of the P wave?
- Represents ventricular depolarization and precedes ventricular contraction
- Represents the movement of the depolarization wave from the SA node through the atria (correct)
- Represents ventricular repolarization
- Represents atrial repolarization
Why is the wave representing atrial repolarization normally obscured by the large QRS complex?
Why is the wave representing atrial repolarization normally obscured by the large QRS complex?
- Because the paths of the depolarization waves through the ventricular walls change continuously
- Because the time required for each ventricle to depolarize depends on its size relative to the other ventricle
- Because repolarization is slower than depolarization
- Because atrial repolarization takes place during the period of ventricular excitation (correct)
How long after the P wave begins does the atria contract?
How long after the P wave begins does the atria contract?
What is the fundamental difference in terms of the length of the absolute refractory period between skeletal muscle fibers and cardiac muscle cells?
What is the fundamental difference in terms of the length of the absolute refractory period between skeletal muscle fibers and cardiac muscle cells?
Why does the long refractory period in cardiac muscle cells prevent tetanic contractions?
Why does the long refractory period in cardiac muscle cells prevent tetanic contractions?
What triggers cardiac muscle contraction?
What triggers cardiac muscle contraction?
What is the special ability of about 1% of cardiac muscle fibers?
What is the special ability of about 1% of cardiac muscle fibers?
In which type of muscle cells does depolarization open fast voltage-gated Na+ channels?
In which type of muscle cells does depolarization open fast voltage-gated Na+ channels?
What is the role of contractile muscle fibers in the heart?
What is the role of contractile muscle fibers in the heart?
What is the main difference between the energy metabolism of cardiac muscle and skeletal muscle?
What is the main difference between the energy metabolism of cardiac muscle and skeletal muscle?
Why is the lack of oxygen supply to the myocardium (heart muscle) more dangerous than the lack of nutrients?
Why is the lack of oxygen supply to the myocardium (heart muscle) more dangerous than the lack of nutrients?
How do the fuel sources used by cardiac muscle and skeletal muscle differ?
How do the fuel sources used by cardiac muscle and skeletal muscle differ?
What is the main advantage of the heart's ability to switch between different metabolic pathways?
What is the main advantage of the heart's ability to switch between different metabolic pathways?
What is the key difference between the energy metabolism of cardiac muscle and skeletal muscle during prolonged exercise?
What is the key difference between the energy metabolism of cardiac muscle and skeletal muscle during prolonged exercise?
What is the main reason why the heart is more dependent on a constant supply of oxygen compared to skeletal muscle?
What is the main reason why the heart is more dependent on a constant supply of oxygen compared to skeletal muscle?
What triggers the release of the other 80% of calcium needed for muscle contraction in cardiac cells?
What triggers the release of the other 80% of calcium needed for muscle contraction in cardiac cells?
Why does the influx of Ca2+ through slow Ca2+ channels trigger the opening of nearby Ca2+-sensitive channels in the sarcoplasmic reticulum (SR)?
Why does the influx of Ca2+ through slow Ca2+ channels trigger the opening of nearby Ca2+-sensitive channels in the sarcoplasmic reticulum (SR)?
What effect does the calcium surge across the sarcolemma have on depolarization potential?
What effect does the calcium surge across the sarcolemma have on depolarization potential?
What role do the K+ channels play during muscle contraction?
What role do the K+ channels play during muscle contraction?
Why is calcium barred from entering nonstimulated cardiac fibers?
Why is calcium barred from entering nonstimulated cardiac fibers?
What is the primary function of slow Ca2+ channels in cardiac muscle cells?
What is the primary function of slow Ca2+ channels in cardiac muscle cells?
What is the primary function of the fibrous pericardium?
What is the primary function of the fibrous pericardium?
Which layer of the pericardium forms a closed sac around the heart?
Which layer of the pericardium forms a closed sac around the heart?
What is the approximate location of the heart in the thorax?
What is the approximate location of the heart in the thorax?
Which statement about the heart's position is correct?
Which statement about the heart's position is correct?
What is the primary function of the serous membrane's parietal layer?
What is the primary function of the serous membrane's parietal layer?
What is the relationship between the heart and the lungs?
What is the relationship between the heart and the lungs?
