Which of the following is one difference between bursae and tendon sheaths?
a. bursae serve as cushioning fat pads between adjacent structures, while tendon sheaths reduce friction between adjacent structures.
b. bursae are only found in synovial joints, while tendon sheaths are only found in fibrous joints.
c. bursae contain a thin film of synovial fluid, while tendon sheaths lack synovial fluid altogether.
d. bursae are flattened fibrous sacs wedged between adjacent structures, while tendon sheaths are elongated fibrous sacs that wrap around tendons.

d. Bursae are flattened fibrous sacs wedged between adjacent structures, while tendon sheaths are elongated fibrous sacs that wrap around tendons.

Explanation:

A bursa is a small pouch full of synovium (which is a fluid discharge) located where a muscle and tendon touch a bone. The bursa is located at this location to reduce friction between bone, muscle and tension. On the other hand, tendon sheaths are structures that form bridges or tunnels between the bone surfaces on which the tendons slide. Its function is to contain the tendon, allowing it an easy gliding.

A significant difference between these two structures is that the bursae are flat fibrous sacs trapped between adjacent structures, while the tendon sheaths are elongated fibrous sacs that surround the tendons.