Tag: biology

Questions Related to biology

State whether the following statements are true or false.
The first heart sound results from a closure of semilunar valves.

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

  1. True

  2. False

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Correct Option: B
Explanation:

Heart sounds are noises generated by the closing and opening of the heart valves. In a healthy individual, there are two normal heart sounds called lub and dub. Lub is the first heart sound. It is associated with the closure of the tricuspid and bicuspid valves at the beginning of systole. The second heart sound dub is associated with the closure of the semilunar valves at the beginning of diastole.

So, the correct option is 'False'.

In heart, automatic rhythmic impulse generation capability is present in the

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

  1. S.A. node

  2. A.V. node

  3. Bundle of His

  4. All of the above

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Correct Option: D
Explanation:
The human heart is a muscular structure made up of involuntary cardiac tissues. The pacemaker of the heart or the SA node generates an electrical impulse that travels across the heart muscles and results in a heartbeat. Sometimes activity of SA node is decreased  by vagus cranial nerve then AV node, Bundle of His and Purkinje fibres together provide Autorhythmicity to the heart.

So, the correct answer is 'All of the above'.

Heart sound which is longer is

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

  1. Lubb

  2. Dub

  3. Both are equal

  4. Sometimes (a) and sometimes (b).

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Correct Option: A

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

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

  1. Contraction of atrial chambers.

  2. Contraction of ventricular chambers.

  3. Closure of the atrioventricular valves.

  4. Relaxation of the semilunar valves.

Show answer
Correct Option: C
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. 

The heart sound 'dupp' is produced when

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

  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.

Show answer
Correct Option: D
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.

The rate of heart beat in a rabbit is nearly

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

  1. 92 per minute

  2. 100 per minute

  3. 150 - 300 per minute

  4. None of the above

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Correct Option: C
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.

Systole is comprised of 

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

  1. Isovolumetric ventricular contraction

  2. Ventricular ejection

  3. Both A and B

  4. Isovolumetric ventricular relaxation

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Correct Option: C
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'

The first heart sound is produced when

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

  1. Intraventricular pressure decreases.

  2. Semilunar valve snaps shut.

  3. Bicuspid and tricuspid valve close quickly.

  4. Diastole begins.

Show answer
Correct Option: C
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.

One heartbeat in an average man lasts  

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

  1. 0.8 second

  2. 0.2 second

  3. 0.5 second

  4. 1 minute

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Correct Option: A
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.

The term cardiac refers to which organ in the body?

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

  1. Heart

  2. Vein

  3. Lymph

  4. Capillary

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Correct Option: A