At this time examine the heart. Notice that this organ is self-contained in a membrane similar to the lungs. These membranes are also specific types of serous membranes. In this case the membranes are visceral and parietal pericardium. Which of these two membranes fit loosely around the heart?

The **parietal pericardium** is the membrane that fits loosely around the heart. Here's a brief overview of both membranes for clarity: 1. **Visceral Pericardium (Epicardium):** - **Location:** Directly adheres to the surface of the heart. - **Function:** Provides a smooth, friction-reducing surface for the heart as it contracts and beats. - **Attachment:** Tightly connected to the heart muscle, making it less flexible. 2. **Parietal Pericardium:** - **Location:** Forms the outer layer of the pericardial sac, surrounding the visceral pericardium. - **Function:** Creates a protective sac with a small amount of lubricating fluid in the pericardial cavity, allowing for smooth movement of the heart within the chest. - **Attachment:** Looser and more flexible compared to the visceral layer, allowing the heart to move freely within the sac. **In summary, the parietal pericardium is the membrane that fits loosely around the heart, providing a protective and flexible outer layer.** **Answer:** The parietal pericardium is the membrane that fits loosely around the heart.