18 Questions
What is the main function of the right side of the heart?
To pump blood to the body against low resistance and under low pressure
What is the main function of the left side of the heart?
To pump blood to the lungs against high resistance and under high pressure
What is the name of the phase in the cardiac cycle when the heart muscle contracts to eject blood?
Systole
What is the name of the phase in the cardiac cycle when the heart muscle relaxes to be filled with blood?
Diastole
What is the name of the wall of the left ventricle?
Thicker than the right ventricle
What is the name of the blood vessels that carry deoxygenated blood from the body to the right atrium?
Superior and inferior vena cava
What is the function of the atrium in the heart?
Serving mainly as a reservoir of blood
During which phase of the action potential does depolarization occur in cardiac muscle fibers?
Phase 0
What is the resting membrane potential of cardiac muscle fibers?
-90 mV
Which ion channels are responsible for the depolarization phase in cardiac muscle fibers?
Voltage-gated Na+ channels
What characterizes the repolarization phase of the action potential in cardiac muscle fibers?
Triphasic and slow process
What is the specific role of ventricular fibers in the heart's action potential?
Generation of action potentials
During which phase of the action potential does the membrane potential return to +10 mV due to the outflow of K+ through K+ channels?
Phase 2: The Plateau
What contributes to the prolonged plateau of the action potential in ventricular fibers?
Continuous efflux of K+
Which phase is characterized by the closure of slow calcium-sodium channels and unopposed outflow of K+ until repolarization is complete?
Phase 3: Rapid repolarization to RMP
What role do slow calcium-sodium channels play during the plateau phase of the action potential?
Balancing the inflow of Ca++ & Na+ with the outflow of K+
What is the membrane potential during Phase 3 of the action potential?
-50 mV
What prevents the heart from developing sustained, tetanic contractions during the absolute refractory period?
Closure of slow calcium-sodium channels
Learn about the phases of the cardiac action potential, including repolarization, the plateau phase, rapid repolarization, and return to the resting membrane potential (RMP). Understand the role of potassium (K+), calcium (Ca++), and sodium (Na+) channels in regulating the membrane potential.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
