Tag: cardiac cycle

Questions Related to cardiac cycle

Which one of the following generates 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: C
Explanation:

Sino-atrial node (SAN) generates the maximum number of action potentials per minute (70-75/min) and therefore, it sets the pace of the activities of the heart. Hence, it is called as the cardiac pacemaker.

The sound of 'lubb' is produced during closure of

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

  1. Bicuspid valve

  2. Tricuspid valve

  3. Semilunar valves

  4. Both A and B

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Correct Option: D
Explanation:
Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. 
In healthy adults, there are two normal heart sounds often described as a 'lubb' and a 'dubb' (or 'dupp'), that occur in sequence with each heartbeat. 
These are the first heart sound and second heart sound, produced by the closing of the AV (atrio ventricular) valves and semilunar valves, respectively. 

Typical 'Iubb'-'dupp' sounds of the heart 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

Show answer
Correct Option: D
Explanation:

During each cardiac cycle two prominent sounds are produced, which can be easily heard through a stethoscope. The first heart sound (lubb) is associated with the closure of the tricuspid and bicuspid valves, whereas the second heart sound (dubb/dupp) is associated with the closure of the semilunar valves. 

Impulse of heart beat originates from

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. Vagus nerve

  4. Cardiac nerve

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Correct Option: A
Explanation:

The sino-atrial node (SAN) can generate the maximum number of action potentials, i.e., 70-75 /min. It is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called as the natural cardiac pacemaker. 

Identify the correct sequence of events in a cardiac cycle.

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

  1. Diastole, atrial systole, ventricular diastole, ventricular systole.

  2. Atrial systole, ventricular systole, atrial diastole, ventricular diastole.

  3. ventricular systole, ventricular diastole, diastole, atrial systole.

  4. Ventricular diastole,diastole, ventricular systole, atrial systole.

Show answer
Correct Option: B
Explanation:

The cardiac cycle starts with atrial systole. It represents the contraction of the myocardium of the left and right atria by which blood is forced into the ventricles. It progresses to ventricular systole, in which the ventricles contract and blood forced  into the aorta and pulmonary artery. After that atrial diastole occurs which means the relaxation of atria.The cardiac cycle ends with ventricular diastole in which ventricles are relaxing and also filling with blood in preparation of the next cycle.


The heart of a healthy man beats normally per minute

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

  1. 85-90 times

  2. 80-90 times

  3. 70-80 times

  4. 60-70 times

Show answer
Correct Option: C
Explanation:

In the human heart, the sino-atrial node (SAN) can generate 70-75 beats/min and is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called the pacemaker. Our heart normally beats 70-75 times in a minute (average 72 beats/min).

So, the correct answer is option C.

The cardiac impules that results into the heart beat is delayed at

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

  1. Internodal tract

  2. AV node

  3. Bundle of His

  4. Purkinje fibre

Show answer
Correct Option: B
Explanation:

The cardiac cycle is regulated by specialized areas in the heart wall, that forms the conduction system of the heart. Two of these areas are tissue mass, called as nodes; the third is a group of fibers, called as the atrio-ventricular bundle. 

The sinoatrial node, which is located in the upper wall of the right atrium and initiates the heartbeat, is called as the pacemaker. The second node, located in the interatrial septum at the bottom of the right atrium, is called as the atrio-ventricular node. 
The rhythmic sequence of contractions (sinus rhythm), is coordinated by the sinoatrial (SA) and atrioventricular (AV) nodes. The sinoatrial node, often known as the cardiac pacemaker, is located in the upper wall of the right atrium and is responsible for the wave of electrical stimulation that initiates atrial contraction by creating an action potential. Once the wave reaches the AV node, situated in the lower right atrium, it is delayed there before being conducted through the bundles of His and back up the Purkinje fibers, leading to a contraction of the ventricles. The delay at the AV node allows enough time for all of the blood in the atria to fill their respective ventricles.

In cardiac circulation, "dupp" sound is heard, when

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

  1. Mitral valves closes

  2. Mitral valves opens

  3. Semilunar valves closes

  4. Tricuspid valve closes

Show answer
Correct Option: C
Explanation:

During each cardiac cycle two prominent sounds are produced, which can be easily heard through a stethoscope. The first heart sound ('lubb') is associated with the closure of the tricuspid and bicuspid valves, whereas the second heart sound ('dubb'/'dupp') is associated with the closure of the semilunar valves. 

Pressure exerted by blood against walls of an artery during ventricular expansion is 

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

  1. Systolic Pressure

  2. Ventricular Pressure

  3. Both A and B

  4. Cardiac output

Show answer
Correct Option: B
Explanation:

The pressure exerted on the arterial wall during left ventricular contraction pushing blood into the aorta. This is called ventricular pressure or ventricular systole. During ventricular systole closing of atrioventricular valves produces the first heart sound lubb. Thus, the correct option is B.

Normal rate of heart beat in a human being is________.

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

  1. 32/minute

  2. 42/minute

  3. 52/minutes

  4. 72/minute

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Correct Option: D
Explanation:
The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat. The frequency of the cardiac cycle or the heart rate is expressed as heart beats per minute. Systole is the contraction of the cardiac muscles in response to an electrochemical stimulus to the heart's cells. It is a force that drives blood out of the heart. Diastole is the period when the heart refills with blood after systole (contraction). The normal rate of heart beat is 72/minute.
So, the correct answer is option D.