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

Circulation was discovered by 

  1. William Harvey

  2. Willian Henry

  3. Michael Harvey

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

The human circulatory system consists of a muscular four-chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated. Circulation was discovered by William Harvey. He was the first to recognize the full circulation of blood in the human body and to provide experiments and arguments to support this idea.

So, the correct answer is 'William Harvey'.

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

Mammalian heart is

  1. Neurogenic

  2. Myogenic

  3. Digenic

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

The human heart is an example of myogenic heart, it possesses cardiac muscle helping the heart to automatically contract spontaneously; which do not need any stimuli as in neurogenic heart. A myogenic heart is capable of generating a cardiac contraction independent of nervous input. In a myogenic heart, contraction is initiated by the cells called myocyte  (Pacemakers)itself instead of an outside occurrence or stimulus such as nerve innervation.

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.
Smaller animals generally have a lower pulse rate than larger animals.

  1. True

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

Smaller animals have much higher metabolism; proportionate to body size, smaller animals tend to have a much smaller heart than larger animals. This means that in order to circulate blood at the same rate, the hearts of smaller animals need to pump more times within a specified time because the volume they can pump each time is smaller.

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

Choose the correct answer from the alternatives given.
Heart sounds are produced by:

  1. contraction of the myocardium

  2. flow of blood in the atria

  3. flow of blood in the ventricles

  4. closure of the heart valves
Reveal answer Fill a bubble to check yourself
D 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 'Closure of the heart valves'.

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

Choose the correct answer from the alternatives given.
The impulses for heart beat originate in:

  1. A.VN.

  2. SAN.

  3. bundles of His

  4. fibres of Purkinje
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sinoatrial node (SAN) is the impulse-generating (pacemaker) tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm. It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava. 

So, the correct option is 'SAN'.

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.
Rate of heart beat is directly proportional to the size of the body.

  1. True

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

The rate of heartbeat is inversely proportional to the size of the body. Smaller animals have a greater heart rate due to increased metabolic rate than the large animals. 

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.
Valves in the cardiovascular system are found only in the heart.

  1. True

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

A valve is a membranous structure present in a hollow organ. It folds or closes to prevent the return flow of the body fluid passing through it. The valves present in between the auricles and ventricles are meant to prevent the backflow of blood from the ventricles to auricles. Valves are also a part of veins.

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

Excessively high heart rate (> 180) can reduce cardiac output because 

  1. Blood is moving too fast through the lungs to pick up enough oxygen

  2. It tires out the heart muscles and so they pump slower

  3. It reduces the time for ventricular filling which reduces stroke volume

  4. The PR-interval increases which leads to longer ventricular diastole and shorter ventricular systole
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Heart rate affects both stroke volume and minute volume by altering the length of diastole and thereby the degree of filling and force of contraction. Minute volume and B.P may rise even if the stroke volume falls. This happens with a moderate rise in the heart rate. But if the heart rate is too high, the stroke volume becomes so low that the minute output falls far below the normal.

During muscular exercise, the output may be 30-40 litres i.e., 6-10 times the normal minute volume( stroke volume 170-200 ml; heart rate 150-180 per minute).
So, the correct answer is 'It reduces the time for ventricular filling which reduces stroke volume'.

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

Bicuspid and tricuspid valves are open during

  1. Ventricular systole

  2. Ventricular diastole

  3. Atrial systole

  4. Late joint diastole
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Atrial systole occurs at the end of ventricular diastole. After the ventricle has pumped its blood, it begins to relax. There is now negative pressure in the ventricle (since it is now empty), and this pressure helps to draw in the blood from the atrium when it enters into systole. So during atrial systole, the bicuspid and tricuspid valves are open, and the pulmonary/aortic semilunar valves are closed. Then during the diastole, the bicuspid and tricuspid valves are closed.