During diastole, the auricles receive **venous blood** from various parts of the body. Let's discuss this in detail:

**1. Diastole and the Cardiac Cycle:**
Diastole is a phase of the cardiac cycle when the heart muscles relax and fill with blood. It is the opposite of systole, which is the contraction phase when the heart pumps blood out. The cardiac cycle consists of two main phases: diastole and systole, which work together to ensure efficient blood circulation throughout the body.

**2. The Function of the Auricles:**
The heart consists of four chambers: two atria (auricles) and two ventricles. The atria are responsible for receiving blood from various parts of the body and pumping it into the ventricles. The auricles play a crucial role in this process by acting as reservoirs that receive and store blood.

**3. Venous Blood:**
Venous blood refers to the deoxygenated blood that has already circulated through the body's tissues and organs, delivering oxygen and nutrients while picking up waste products such as carbon dioxide. This deoxygenated blood is collected by the veins and then directed towards the right atrium of the heart.

**4. The Right Atrium and Diastole:**
During diastole, the right atrium receives blood from two main sources: the superior vena cava and the inferior vena cava. The superior vena cava collects deoxygenated blood from the upper body, including the head, neck, and upper limbs. The inferior vena cava collects deoxygenated blood from the lower body, including the abdomen, pelvic region, and lower limbs.

**5. Mixing of Blood:**
As the right atrium receives blood from the superior and inferior vena cava, the deoxygenated blood mixes with a small amount of oxygenated blood from the coronary sinus. The coronary sinus collects oxygen-depleted blood from the heart muscle itself.

**6. Transfer to the Right Ventricle:**
Once the right atrium is filled with blood during diastole, the tricuspid valve between the right atrium and the right ventricle opens. This allows the venous blood to flow into the right ventricle, which will later pump it to the lungs for oxygenation.

In summary, during diastole, the auricles receive venous blood from the superior and inferior vena cava, as well as a small amount of oxygen-depleted blood from the coronary sinus. This blood will later be pumped to the lungs for oxygenation before being circulated to the rest of the body.

venous blood