What should be the condition of the atria during mid-diastole?

During mid-diastole, the condition of the atria is that they are relaxed. This phase occurs following the closure of the atrioventricular (AV) valves and the filling of the ventricles with blood coming from the atria. The relaxation of the atrial musculature allows for the passive filling of the atria as blood flows in from the superior and inferior vena cava into the right atrium and from the pulmonary veins into the left atrium.

This relaxation is crucial for maintaining proper hemodynamics and ensuring adequate filling of the ventricles before they contract in the subsequent phase of the cardiac cycle, known as systole. During this time, it is important for the heart to be in a state of relaxed filling to optimize the stroke volume when the ventricles eventually contract. The other states described, such as contracting, overflowing, or blocked, do not accurately reflect the physiological conditions in the atria during mid-diastole.