Podcast
Questions and Answers
What is the main cause of the contraction of cardiac muscle (systole)?
What is the main cause of the contraction of cardiac muscle (systole)?
- Opening of voltage gated Na+ channels
- Closing of sodium ion channels and the opening of potassium ion channels
- Excessive influx of anions (Cl– ions)
- Closing of voltage gated Ca+2 channels (correct)
What is the process that results in the return of ions to their previous resting state in cardiac muscle?
What is the process that results in the return of ions to their previous resting state in cardiac muscle?
- Conductivity
- Refractory Period
- Repolarization (correct)
- Hyperpolarization
What causes hyperpolarization in cardiac muscle?
What causes hyperpolarization in cardiac muscle?
- Closing of potassium ion channels
- Influx of anions (Cl– ions) through chloride channels (correct)
- Excessive efflux of potassium due to open channels
- Opening of voltage gated Na+ channels
What does the refractory period refer to in excitable membranes?
What does the refractory period refer to in excitable membranes?
From where does the cardiac electric impulse originate in the heart?
From where does the cardiac electric impulse originate in the heart?
What role does the AV node play in the heart's conductive system?
What role does the AV node play in the heart's conductive system?
What is responsible for transmitting the cardiac electric impulse from the AV node to the right and left ventricles?
What is responsible for transmitting the cardiac electric impulse from the AV node to the right and left ventricles?
What is the final step in the heart's conductive system?
What is the final step in the heart's conductive system?
What is the primary characteristic of the cardiac muscle?
What is the primary characteristic of the cardiac muscle?
Which cells in the heart can generate action potential spontaneously?
Which cells in the heart can generate action potential spontaneously?
What is the normal pacemaker of the heart?
What is the normal pacemaker of the heart?
What factor can cause an increase in heart rate (↑HR)?
What factor can cause an increase in heart rate (↑HR)?
During which phase of action potential does depolarization occur?
During which phase of action potential does depolarization occur?
What causes a large influx of sodium ions inside the cardiac cell during depolarization?
What causes a large influx of sodium ions inside the cardiac cell during depolarization?
Which type of stimulation can lead to a decrease in heart rate (↓HR)?
Which type of stimulation can lead to a decrease in heart rate (↓HR)?
What is the primary function of the SA node in the heart?
What is the primary function of the SA node in the heart?
