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

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

  1. Remains constant

  2. Decreases

  3. Increases

  4. Become erratic.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cardiac output is the product of stroke volume and heart rate. If cardiac output remains relatively constant and stroke volume increases, the heart rate must decrease to maintain the same output.

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

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

  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.
Reveal answer Fill a bubble to check yourself
C Correct answer
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.
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 is determined by

  1. SA node

  2. AV node

  3. Purkinie fibre

  4. Papillary muscles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The SA node acts as the primary pacemaker of the heart, setting the rhythm and rate of the heartbeat. The other structures listed are part of the conduction system but do not set the primary rate.

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

In which type of stole, does phloem surround the xylem both externally and internally?

  1. Amphiphloic siphonostele

  2. Ectophtoic siphonostele

  3. Haplostele

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

In an amphiphloic siphonostele, the phloem is found on both the outer and inner sides of the xylem. This is a specific type of vascular arrangement in certain plants.

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

The rate conduction of impulse in the conducting system of heart is fastest in

  1. Atrial muscles

  2. Bundle of His

  3. Purkinje's fibres

  4. AV node
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the cardiac conduction system, Purkinje fibers have the fastest rate of impulse conduction, allowing the ventricles to contract rapidly and uniformly from the apex upward.

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

State whether the following statements are true or false.
Human heart is neurogenic because the heart beat originates in the nodal tissues.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The heart is entirely made up of cardiac muscles. Muscle cells are also called myocytes. The control of the heart function is by a set of muscles or special node of the modified heart muscle, the sinoatrial node (SAN) located in the atria, so the heart is, therefore, called myogenic.

So, the correct option is 'False'.

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

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.

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

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

  1. S.A. node

  2. A.V. node

  3. Bundle of His

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.
Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

Heart sound which is longer is

  1. Lubb

  2. Dub

  3. Both are equal

  4. Sometimes (a) and sometimes (b).
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The first heart sound, 'Lubb', is caused by the closure of the atrioventricular valves. It is longer and lower in pitch compared to the second heart sound, 'Dub', which is caused by the closure of the semilunar valves.