Question
Question: Each heartbeat generates how many pulses in the arteries A. Two B. Three C. One D. Five...
Each heartbeat generates how many pulses in the arteries
A. Two
B. Three
C. One
D. Five
Solution
Hint:- In humans, the circulation of the blood is called double circulation. This form of circulation involves the flow of both deoxygenated (impure) blood (due to tissue metabolism carbon dioxide is added) and oxygenated (pure) blood (oxygen is in large amounts) in the body.
The deoxygenated blood leaves the tissues, reaches the heart and then enters into lungs. In the lungs, it gets purified and then comes back to the heart and then this oxygenated blood is pumped into the whole body.
Complete Answer:-
The human heart is made up of myocardial tissue. This type of tissue is specialised in for initiation and conduction of the cardiac impulse. Its fibres are finer than other myocardial fibres, these are completely cross striated and possess special nerve-like properties, that is they are self excitatory.
The conducting system has the following parts named as- SA node, internodal pathway, AV node, the bundle of His and Purkinje fibres.
The sequential changes which take place in the heart are called a cardiac cycle. One cardiac cycle includes following phases named as ventricular systole (ventricular contraction), ventricular diastole (ventricular relaxation), atrial systole, atrial diastole and joint diastole.
When the ventricles contract, pressure starts increasing in the ventricles. Due to an increase in this pressure cuspid valves are closed producing LUBB sound. As the ventricular pressure increases more and more, the semilunar valves start opening and the blood starts flowing into the pulmonary artery and aorta.
Now as the blood flows into these vessels, the ventricular Pressure gradually starts decreasing. As a result of this decrease in pressure, semilunar valves close and a DUP sound is produced.
Now as the atria are receiving blood from the vena cava and pulmonary veins, the pressure inside them starts increasing. As the atrial pressure starts increasing, cuspid valves open and blood will enter into ventricles and the complete cycle will repeat itself.
This rhythmic contraction and relaxation of the heart are called the heartbeat. Contraction and relaxation occur separately in atria and ventricles.
Thus each cardiac cycle represents one heartbeat. As heart rate and pulse rate are equal thus each heartbeat generates one pulse in the blood vessels.
Thus the correct answer is option C.
Note:- The action potential travels rapidly through both atria generated by the SA node and then through the AV bundle into the wall of ventricles.
The process of heartbeat begins from the time of embryonal development. Once the heartbeat starts, it continues throughout life. In resting state, in one minute the heartbeats around seventy-two times and during this one minute approximately five litres of blood are pumped to different parts of the body.