Anatomy Practice Exam

Which type of membranes secrete lubricating fluid to reduce friction between organs?

1. Serous membranes

2. Mucous membranes

3. Synovial membranes

4. Cutaneous membranes

The correct answer is: Serous membranes

The type of membranes that secrete lubricating fluid to reduce friction between organs is serous membranes. These membranes are composed of a layer of mesothelium (a type of epithelium) and a layer of connective tissue. They line body cavities that do not open directly to the exterior and cover the organs within those cavities. Serous membranes produce a serous fluid, which acts as a lubricant, preventing friction between organs as they move. This is particularly important in areas such as the thoracic cavity (parietal pleura covering the thoracic wall and visceral pleura covering the lungs) and the abdominal cavity (peritoneum). The lubrication provided by serous fluid allows internal organs to glide smoothly over one another during movements such as breathing or digestion, enhancing overall organ function and health. While mucous membranes do secrete mucus for lubrication, they are primarily involved in protecting and moisturizing passages that open to the exterior, not between internal organs. Synovial membranes, on the other hand, specifically line joint cavities and secrete synovial fluid, which serves to lubricate joints rather than organs. Cutaneous membranes refer to the skin, which is protective but does not serve the function of lubricating between organs.