Tag: heart beat

Questions Related to heart beat

The hormone that stimulates heart beat is

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

  1. Thyroxine

  2. Adrenaline

  3. Glucagon

  4. Gastrin.

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Correct Option: B

Heart beats originate from

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

  1. Left atrium

  2. Right ventricle

  3. Cardiac muscles

  4. Pace maker.

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Correct Option: D

Which one regulates heart beat?

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

  1. Purkinje fibres

  2. Cardiac branch of vagus nerve

  3. SA node

  4. AV node.

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Correct Option: B

Origin of heart beat and its conduction is represented by

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

  1. AV node $\rightarrow$ Bundle of His $\rightarrow$ SA node $\rightarrow$ Purkinje fibres

  2. SA node $\rightarrow$ Purkinje fibres $\rightarrow$ AV node $\rightarrow$ Bundle of His

  3. Purkinje fibres $\rightarrow$ AV node $\rightarrow$ SA node $\rightarrow$ Bundle of His

  4. SA node $\rightarrow$ AV node $\rightarrow$ Bundle of His $\rightarrow$ Purkinje fibres

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Correct Option: D
Explanation:

  • The impulse for heart beat is originated in SA node. It is known as the pace maker of heart and situated in upper right corner of right atrium. 
  • The electrical impulses generated by SA node are conducted to Atrio Ventricular or AV node. 
  • From the AV node, the impulses are transmitted to AV bundle, known as bundle of His which convey the impulses of contraction to the apex of myocardium. 
  • The impulses cause the Purkinje fibres to sweep upwards and outwards which results in pumping of blood into aorta and pulmonary artery.
  • So, the correct sequence of propagation of cardiac impulse is SA node, AV node, Bundle of His, Purkinje fibres.
So, the correct answer is 'SA node →→ AV node →→ Bundle of His →→ Purkinje fibres'.

Typical 'lubb-dup' sounds heard in heart beat are due to

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

  1. Closing of bicuspid and tricuspid valves

  2. Closing of semilunar valves

  3. Blood under pressure through aorta

  4. Closure of bicuspid-tricuspid valves followed by semilunar valves

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Correct Option: D
Explanation:
Heart produces two distinct sounds that can be heard with the help of stethoscope. These are 'lubb' and 'dup'.
  • Lubb is the first sound which has a low pitch and produced by the closure of tricuspid and bicuspid valves (collectively called atrioventricular valves) at the beginning of ventricular systole.
  • Dup is the second sound which is sharp and has a high pitch. It is produced by closure of semilunar valves by the end of ventricular systole and beginning of ventricular diastole).
So, the correct answer is 'Closure of bicuspid-tricuspid valves followed by semilunar valves'.

The first heart sound is

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

  1. Lubb during closure of semilunar valves

  2. Dupp during closure of semilunar valves

  3. Lubb during closure of atrioventricular valves

  4. Dupp during closure of atrioventricular valves

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Correct Option: C
Explanation:
When the heart beats, it produces sounds that can be heard by stethoscope. There are four heart sounds which are designated as S1, S2, S3 and S4.
  • S1: It is the first sound 'lubb'. It has slow pitch and produced by closure of atrioventricular valves at the beginning of ventricular systole.
  • S2: It is the second sound 'dup'. It is sharper and has high pitch. It is produced by closure of semilunar valves by the end of ventricular systole. 
  • S3 and S4 are usually faint and may not be audible. S3 is produced during ventricular filling of heart and S4 is produced during atrial systole.
So, the correct answer is 'Lubb during closure of atrioventricular valves'.

Pulse is a direct measure of

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

  1. Blood pressure

  2. Cardiac output

  3. Stroke volume

  4. Heart rate.

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Correct Option: D

What will be the number of heart beats per minute, if the stroke volume of heart increases, with total volume of blood remains same

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

  1. Remains constant

  2. Decreases

  3. Increases

  4. Become erratic.

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Correct Option: B

Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound in heard when :

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

  1. AV valves open up

  2. Ventricular walls vibrate due to gushing in of blood from artia.

  3. Semilunar valves close down after the blood flows into vessels from ventricles.

  4. AV node recives signal from SA node.

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Correct Option: C
Explanation:
During each cardiac cycle, two prominent sounds are produced which can be easily heard through a stethoscope. The first sound (lub) is associated with the closure of the tricuspid and bicuspid valves during ventricular systole to prevent the backflow of blood to atria. The second sound (dub) is associated with the closure of semilunar valves during ventricular diastole to prevent the backflow of blood to ventricles.

The rate of heart beat is determined by

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

  1. SA node

  2. AV node

  3. Purkinie fibre

  4. Papillary muscles

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Correct Option: A