The CORRECT order of duration of various phases of the cardiac cycle is

Options

A. Atrial systole `gt` Ventricular diastole `gt` Joint diastole `gt` Ventricular systole `gt` Atrial diastole
B. Atrial systole `gt` Ventricular systole `gt` Joint diastole `gt` Ventricular diastole `gt` Atrial diastole
C. Atrial diastole `gt` Ventricular diastole `gt` Joint diastole `lt` Ventricular diastole `lt` Atrial diastole
D. Joint diastole `lt` Ventricular diastole `lt` Atrial diastole

Answer

To determine the correct order of duration of various phases of the cardiac cycle, we need to understand the phases involved in the cardiac cycle and their sequence. The cardiac cycle consists of several phases:

1. **Atrial Systole**: This is the phase when the atria contract, pushing blood into the ventricles.
2. **Ventricular Diastole**: During this phase, the ventricles relax and fill with blood from the atria.
3. **Joint Diastole**: This is the period when both the atria and ventricles are relaxed, allowing for filling of the heart chambers.
4. **Ventricular Systole**: In this phase, the ventricles contract, pumping blood into the arteries.
5. **Atrial Diastole**: This is the phase when the atria are relaxed and filling with blood.

Now, let's arrange these phases in the correct order based on their duration:

1. **Atrial Systole**
2. **Ventricular Diastole**
3. **Joint Diastole**
4. **Ventricular Systole**
5. **Atrial Diastole**

Thus, the correct order of duration of various phases of the cardiac cycle is:

**Atrial Systole → Ventricular Diastole → Joint Diastole → Ventricular Systole → Atrial Diastole**