Question

The veins of the heart muscle merge to form the _____________________ which empties into the __________________ .

The fetal lung bypass from the pulmonary trunk to the aorta closes at birth and becomes ______________________________.

The stabilizing “strings” of the tricuspid and bicuspid valves are called ___________________________.

The muscular ridges inside the ventricles are called ________________________________________.

During ventricular systole, the AV valves are: open or closed

During ventricular systole (the ventricular ejection phase), the semilunar valves are: open or closed

During isovolumetric relaxation, the semilunar valves and AV valves are: open or closed

Answer 1

Answer:

1. The veins of heart muscle merge to form the coronary sinus which empties into the right atrium.

Explanation: The group of veins that merges to form coronary sinus it collects the blood from the muscles of heart and it drains into the right atrium of heart. The blood which collecting are poorly oxygenated and it send to the right atrium for purification.

2. The fetal lung bypass from the pulmonary trunk to aorta and closes at birth and become ligamentum arteriosum.

Explanation: In the fetal circulation, thee structure which connects the pulmonary trunk to aorta is called ductus arteriosis after the birth is changed into ligamentum arteriosum.

3. The stabilizing strings of the Tricupsid and Bicupsid valve are called chordae tendineae.

Explanation: Chordae tendineae is also known as heart strings. It is leaflet like structure which provides stability to Tricupsid and Bicupsid valves. It helps to avoid prolapse of valves and it also prevents back flow of blood i.e regurgitation

4. The muscular ridges inside the ventricles is called trabeculae carneae.

Explanation: Trabeculae carneae is also known as meaty ridges. These are muscular ridges which is present inside the both right and left Ventricles of heart. It helps to prevent the blood backflow in both Bicupsid and Tricupsid valve.

5. Answer: During the ventricular systole the AV valves are closed

Explanation: In ventricular systole, the pressure in the Ventricles get increase due to increase in pressure made the AV valves to close or shut.

6. During the ventricular systole the semilunar valves get open.

Explanation: During the ventricular systole (ejection phase) the muscles of the ventricle get contracts and the pressure inside the ventricles get incresed and the blood get ejected out due to this contraction the semilunar valves get open.

7. During the isovolumetric contraction, the semilunar valves and AV valves get closed.

Explanation: During the isovolumetric contraction the semilunar valves such as aortic valves and pulmonary valves get closed and the Atrioventricular valves also get closed. In this period the Ventricles of the heart get contracts but it is not enough to open these valves.