Tag: cardiac cycle

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Questions Related to cardiac cycle

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

The heart sounds normally heard by a physician while holding a stethoscope onto the left side of the chest of the patient are due to

  1. Contraction of atrial chambers.

  2. Contraction of ventricular chambers.

  3. Closure of the atrioventricular valves.

  4. Relaxation of the semilunar valves.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In healthy adults, there are two normal heart sounds often described as a lub and a dub, that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves (AV) and semilunar valves respectively. 

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

The heart sound 'dupp' is produced when

  1. Tricuspid valve is opened.

  2. Mitral valve is opened.

  3. Mitral valve is closed.

  4. Semi-lunar at the base of aorta get closed.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Heart sounds are heard on the surface of the chest in the heart region; they are amplified by and heard more distinctly through a stethoscope. They are caused by the vibrations generated during the normal cardiac cycle and may be produced by muscular action, valvular actions, motion of the heart, or blood passing through the heart. The second heart sound (S2) is shorter and higher pitched than the first, is heard as a dupp and is produced by closure of the aortic and pulmonary valves.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

The rate of heart beat in a rabbit is nearly

  1. 92 per minute

  2. 100 per minute

  3. 150 - 300 per minute

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cardiac output is estimated by heart beat. The amount of blood pumped by the heart per minute is known as cardiac output. Small mammals have high metabolic rates so they faster heart rates than larger-sized mammals. A rabbit at rest normally has a heart rate that ranges from 140 to 180 beats per minute. Stress can cause the heart rate to increase, and the rate in a stressed rabbit can be quite high: well over 300 beats per minute. Therefore the rate of the heartbeat in a rabbit can be ~ 150-300 per minute. 

So, the correct answer is option C.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

Systole is comprised of 

  1. Isovolumetric ventricular contraction

  2. Ventricular ejection

  3. Both A and B

  4. Isovolumetric ventricular relaxation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Systole is the phase of the contraction of the heart while diastole is the phase of the relaxation. During the ventricular systole the following events take place:

1. Isovolumetric ventricular contraction is the phase during which the pressure builds up in the ventricles but it is not enough to open the semi-lunar valves of the pulmonary artery and aorta.
2. The contraction of ventricles continue and reach up to the level where the blood pressure opens up the semi-lunar valves and the blood is ejected out into the pulmonary artery and aorta.
Hence, the correct answer is 'Both A and B'

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

The first heart sound is produced when

  1. Intraventricular pressure decreases.

  2. Semilunar valve snaps shut.

  3. Bicuspid and tricuspid valve close quickly.

  4. Diastole begins.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The lub is the first heart sound, commonly termed S1, and is caused by turbulence caused by the closure of mitral and tricuspid valves at the start of systole. The second sound, dub or S2, is caused by the closure of aortic and pulmonary valves, marking the end of systole.

So, the correct answer is option C.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

One heartbeat in an average man lasts  

  1. 0.8 second

  2. 0.2 second

  3. 0.5 second

  4. 1 minute
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One heartbeat in an average man lasts  0.8 second.

Heart rate, also known as pulse, is the number of times a person's heart beats per minute. A normal heart rate depends on the individual, age, body size, heart conditions, whether the person is sitting or moving, medication use and even air temperature. Even emotions can have an impact on heart rate. For example, getting excited or scared can increase the heart rate. But, most importantly, getting fitter lowers the heart rate, by making heart muscles work more efficiently.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

Heart rate is same as

  1. Flow rate

  2. Pulse rate

  3. Breath rate

  4. Inhalation rate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This sequential event in the heart which is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles. Each cardiac cycle represents one heartbeat. The number of heart beats per minute in resting person is called as normal heart rate. The normal heart rate is about 72 beats per minute. The heart rate is same as pulse rate because the contractions of the heart cause an increase in blood pressure in arteries that leads to noticeable pulse.

So, the correct answer is 'Pulse rate'.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

Seema was running. The supply of oxygen to muscles will __________.

  1. Remain same

  2. Increase

  3. Decrease

  4. Decrease and then increase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
During exercise body's muscles increase their activity level and consumes more oxygen. Hence to meet the oxygen demand of the muscles Heart rate and blood pressure increases which leads to flooding of muscles with oxygen. Hence when Seema was running, if checked immediately her heart rate will be found increased.
So, the correct answer is 'Increase'.