Question

During joint diastole
A. Tricuspid and bicuspid valve are open
B. Semilunar valves are closed
C. All the four chambers of the heart are in relaxed state
D. All of the above

Answer 1

Hint: The right auricle receives deoxygenated blood from the superior and inner vena cava during this process, and the left auricle receives oxygenated blood from the pulmonary vein from the lungs. The AV valves are always open between the auricle and the ventricle, and blood flows from the auricle to the ventricle.

Complete Answer:
The cardiac cycle is the human heart's performance from the end of one heartbeat to the start of the next. It consists of two periods: one during which, after a duration of robust contraction and pumping of blood, the heart muscle relaxes and refills with blood called diastole, dubbed systole.

When all four chambers of the heart, known as joint diastole, are in a comfortable state. Blood reaches the corresponding auricles via veins during the joint diastole stage.
Due to this blood filling, atrioventricular valves (Bicuspid and Tricuspid valves) open during joint diastole and allow blood to flow from the atria to the ventricles and semilunar valves are closed.

The ventricles and auricles are concurrently in the diastolic process. The pressure in the ventricles falls below that of the broad arteries as the ventricular diastole progresses. Thus the semilunar valves close quickly to stop the backflow of blood from large arteries into the ventricles. At the start of ventricular diastole, this rapid closing of semilunar valves produces "Dup" second heart sound or diastolic sound.

The state of the heart valves is demonstrated by the quality of heart sounds. Defective or impaired heart valves lead either from ventricles to auricles or from aortae to ventricles to the backflow of blood. The odd hissing sound called "Murmur" can detect such defects. Defective valves might be surgically removed or fixed. Rheumatic fever and syphilis cause wheezing. The system used to magnify and record the sound of the heart is called the Phonocardiogram.


The correct Answer is option (D) All of the above.

Note: Blood from broad veins and coronary sinus flows into the atria during joint diastole, and some blood also passes from the auricles into the respective soothing ventricles due to less ventricle pressure. This process takes just 0.4 seconds and is often referred to as the heart cycle that receives blood. A cardiac cycle is thus completed within 0.8 seconds.