1.
An average heartbeat, or cardiac cycle, lasts approximately:
Correct Answer
C. 0.80 seconds
Explanation
The correct answer is 0.80 seconds. An average heartbeat, or cardiac cycle, refers to the time it takes for the heart to complete one full cycle of contraction and relaxation. The normal resting heart rate for adults is around 60-100 beats per minute, which translates to approximately 0.60-1.00 seconds per beat. Therefore, 0.80 seconds falls within this range and is a reasonable estimate for the duration of an average heartbeat.
2.
_____________ represents ventricular relaxation and filling phases.
Correct Answer
B. Diastole
Explanation
Diastole represents ventricular relaxation and filling phases. During diastole, the ventricles of the heart are relaxed and blood is allowed to flow into them from the atria. This is the phase where the heart is filling with blood in preparation for the next contraction. Systole, on the other hand, represents the contraction phase of the ventricles where blood is pumped out of the heart. Plateau phase and latch state are not terms commonly used to describe the cardiac cycle.
3.
__________ represents ventricular contraction and ejection phases.
Correct Answer
A. Systole
Explanation
Systole represents the phase of the cardiac cycle when the ventricles contract and eject blood into the arteries. This phase is characterized by increased pressure in the ventricles, causing the semilunar valves to open and blood to be pumped out of the heart. During systole, the atria are relaxed and filling with blood for the next cycle.
4.
Name the three phases of the Cardiac Cycle in order.
Correct Answer
C. Mid-to-Late Diastole, Ventricular Systole, Early Diastole
Explanation
The correct order of the three phases of the Cardiac Cycle is Mid-to-Late Diastole, Ventricular Systole, Early Diastole. During Mid-to-Late Diastole, the heart is relaxed and filling with blood. Ventricular Systole follows, where the ventricles contract, forcing blood out of the heart. Finally, Early Diastole occurs, which is a brief period of relaxation before the next cycle begins.
5.
During the Mid-to-Late Diastole, the heart is in complete relaxation, and the pressure in the heart is low.
Correct Answer
A. True
Explanation
During the Mid-to-Late Diastole, the heart is in complete relaxation, meaning that the heart muscles are not contracting. This relaxation allows the heart chambers to fill with blood, resulting in a low pressure within the heart. Therefore, the statement that the pressure in the heart is low during this phase is true.
6.
When is the ventricular blood volume higher?
Correct Answer
A. At the beginning of the systole
Explanation
During systole, the ventricles contract and pump blood out of the heart. This contraction causes an increase in pressure within the ventricles, which leads to a decrease in ventricular blood volume. Therefore, at the beginning of systole, the ventricular blood volume is higher compared to later stages of the cardiac cycle such as diastole or mid-to-late diastole.
7.
Atrial contraction accounts for most of the ventricular filling.
Correct Answer
B. False
Explanation
This statement is false because ventricular filling is primarily due to the relaxation of the ventricles, not atrial contraction. During diastole, the ventricles relax and blood flows passively from the atria into the ventricles due to the pressure difference. Atrial contraction, also known as atrial systole, occurs just before ventricular systole and helps to push the remaining blood into the ventricles, but it does not account for most of the ventricular filling.
8.
Which of the following is NOT true for ventricular systole?
Correct Answer
D. The ventricles relax
Explanation
During ventricular systole, the ventricles contract to pump blood out of the heart. The atrioventricular valves close to prevent backflow of blood into the atria. The semilunar valves open to allow blood to be ejected into the arteries. However, the statement "The ventricles relax" is not true for ventricular systole. Ventricular relaxation occurs during ventricular diastole, the period of the cardiac cycle when the ventricles are filling with blood.
9.
The semilunar valves close during:
Correct Answer
B. Ventricular diastole
Explanation
During ventricular diastole, the semilunar valves close. This is because ventricular diastole is the phase of the cardiac cycle where the ventricles relax and fill with blood. As the ventricles relax, the pressure in the ventricles decreases, causing the blood to flow back towards the ventricles. The closure of the semilunar valves prevents the backflow of blood into the ventricles, ensuring that the blood flows in the correct direction, from the atria to the ventricles and then out to the arteries.
10.
The atrioventricular valves open during:
Correct Answer
B. Ventricular diastole
Explanation
During ventricular diastole, the ventricles relax and fill with blood. As the pressure in the ventricles decreases, the atrioventricular valves (tricuspid and mitral valves) open, allowing blood to flow from the atria into the ventricles. This phase of the cardiac cycle facilitates the filling of the ventricles in preparation for the subsequent contraction (ventricular systole).
11.
The ventricles begin to fill during ventricular diastole.
Correct Answer
A. True
Explanation
Ventricular diastole is the phase of the cardiac cycle during which the ventricles relax and the heart fills with blood. It follows ventricular systole, the phase during which the ventricles contract and pump blood out of the heart. The relaxation of the ventricles lowers their internal pressure, causing the atrioventricular valves (the mitral and tricuspid valves) to open and allow blood to flow from the atria into the ventricles. Therefore, the ventricles indeed begin to fill with blood during ventricular diastole.
12.
What is the definition of the Cardiac Cycle?
Correct Answer
A. Cardiac Cycle refers to the sequence of events that occur during one complete heartbeat.
Explanation
The correct answer is "Cardiac Cycle refers to the sequence of events that occur during one complete heartbeat." This definition accurately describes the cardiac cycle, which includes the contraction of the atria, the contraction and relaxation of the ventricles, and the circulation of blood in the heart. It encompasses all the necessary events that take place during a single heartbeat.
13.
Dicrotic notch involve which part of the heart?
Correct Answer
B. Aortic pressure
Explanation
The dicrotic notch involves the aortic pressure. The dicrotic notch is a small dip or notch that occurs in the aortic pressure waveform during ventricular diastole. It is caused by the closure of the aortic valve, which briefly interrupts the flow of blood from the left ventricle into the aorta. This interruption creates a small dip in the aortic pressure waveform, known as the dicrotic notch. Therefore, the correct answer is Aortic pressure.
14.
What is the first phase in cardiac cycle?
Correct Answer
A. Passive Filling
Explanation
Passive Filling is the first phase in the cardiac cycle. During this phase, the heart is relaxed, and the blood flows passively from the atria to the ventricles. The atria are filled with blood from the veins, and as the ventricles expand, they create a pressure gradient that allows the blood to flow into the ventricles. This phase is crucial for filling the ventricles with blood before the next phase of the cardiac cycle, ventricular isovolumic contraction, begins.
15.
If a patient has heart beat of 90bpm, what is the duration of the beats?
Correct Answer
D. 0.6
Explanation
The duration of the beats is 0.6. This can be calculated by dividing 60 seconds (the number of seconds in a minute) by the heart rate of 90 beats per minute. This calculation gives us 0.6 seconds, which represents the duration of each beat.