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ANSWER B: An atrioventricular (AV) node conduction delay is indicated by a prolonged PR interval (more than 0.20 seconds). This is referred to as a first-degree AV block, and although it is typically asymptomatic, an ECG can show it.
ANSWER B :
The ventricles produce higher electrical activity because they have bigger muscle mass. The reason for this is that because the ventricles are bigger and stronger than the atria, their electrical depolarization causes a greater voltage change, which raises the amplitude of the QRS complex. Because it reflects the atria's lower depolarization, the P wave is smaller.
ANSWER C:
The end-diastolic volume (EDV), which is equivalent to the volume of blood in each ventricle at the conclusion of atrial systole, is 130 milliliters. Prior to contraction, it symbolizes the ventricle's maximum blood volume.
ANSWER : C
Elevated blood pressure forces the heart to pump harder, leading to increased myocardial oxygen demand and potential hypertrophy over time. The heart's increased workload may lead to heart failure, where the heart struggles to maintain adequate blood circulation throughout the body.
ANSWER : B
Purkinje fibers are specialized cardiac muscle fibers that facilitate rapid conduction of electrical impulses, ensuring synchronized ventricular contraction. They originate from the bundle of His and spread throughout the ventricular myocardium, allowing for efficient pumping of blood.
ANSWER: C
The dicrotic notch represents a brief rise in aortic pressure following the closure of the aortic valve, due to elastic recoil.
ANSWER : B
Fibrillation is a chaotic contraction pattern, especially dangerous when it occurs in the ventricles (ventricular fibrillation).
ANSWER : B
The AV node slows down the signal from the SA node, giving the atria time to contract before the ventricles are stimulated.
ANSWER : C
Sympathetic stimulation increases heart rate and contractility to meet the body’s increased demand for blood and oxygen.
ANSWER : C
During ventricular contraction, known as systole, pressure increases within the ventricles, leading to the opening of the semilunar valves.The closure of the atrioventricular valves prevents backflow of blood into the atria, ensuring efficient blood flow into the arteries.