This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Normal Fluid level in the pericardial cavity: 
Select and explain. 
A. 50 ml, B. 100 ml, C. 150 ml, D. 200 ml
A: 50 ml
Answer: A: 50 ml 
Explanation: The visceral layer is closely applied to the hea and is often called the epicardium.The slitlike space between the parietal and visceral layers is referred to as the pericardial cavity.Normally, the cavity contains a small amount of tissue fluid (about 50 mL), the pericardial fluid, which acts as a lubricant to facilitate movements of the hea.