Question

During isovolumetric relaxation, what closes the semilunar valves?

Answer 1

“The Cardiovascular System: Cardiac Cycle

1.
Valves open in response to _________________ on their two sides.
Blood pressure
2.
List the chambers/ vessels that the four valves connect:
______(1)______ Pulmonary semilunar ______(2)_____
______(3)______ Aortic semilunar ______(4)_____
______(5)______ Mitral ______(6)_____
______(7)______ Tricuspid ______(8)_____
1. R. ventricle
2. Pulmonary artery
3. L. ventricle
4. Aorta
5. L. atrium
6. Pulmonary vein
7. R. atrium
8. Inferior/superior vena cava
3.
a. Ventricular filling occurs during______ ventricular_________.
b. Blood flows through the _______ or __________ valves into the ventricles.
1. Mid-late
2. Diastole
3. Mitral
4. Tricuspid
4.
During Ventricular systole, what closes the AV valves?
Intraventricular pressure rising and causing ventricular contractions.
5.
During ventricular systole, what opens the semilunar valves?
Ventricles contract, raising pressure, bblood pressure then forces the semilunar valves open.
6.
During Isovolumetric relaxation, what closes the semilunar valves?
When blood pressure in the artery exceeds the blood pressure in the ventricle.
7.
During Isovolumetric relaxation, what opens the AV valves?
When blood pressure in the ventricle exceeds the blood pressure in the arteries.
8.
Why is hypertension hard on the heart?
Beacuse overtime high blood pressure causes heart muscles to thicken, which means more work to pump blood through vessels. It can cause heart disease because of heart constantly overworking.
9.
Looking at the ventricular volume graph, the stroke volume is approximately how many ml?
70ml
10.
During the four phases listed below, state whether the AV and semilunar valves are opened or closed:
1. Ventricular Filling
2. Isovolumetric
3. Ventricular Ejection
4. Isovolumetric
1. AV: Opened, Semilunar: Closed
2. AV: Closed, Semilunar: Closed
3. AV: Closed, Semilunar: Opened
4. AV: Closed, Semilunar: Closed”

Answer 2

bloodflow back toward the heart

Step-by-step explanation:

During phase of the ventricular diastole, as the relaxation of the ventricular muscle takes place, the pressure on remaining blood within ventricle begins to fall down. When the pressure within ventricles drops below the pressure in both pulmonary trunk as well as aorta, the blood flows back toward heart, producing dicrotic notch which is seen in the blood pressure tracings. Semilunar valves thus close to prevent the backflow into heart.