Which of the following statements concerning bursae is true? Select one: a. They are filled with air. b. They are a cellular cushion. c. They carry blood vessels to joints. d. They are formed by an extension of the synovial membrane. e. They bind tendons to ligaments.

D

Explanation:

Bursae is defined as a small fluid filled sac that functions as a gliding surface to reduce friction between tissues of the body. Bursae are made up of Synovial membrane which secretes synovial fluid contained within the bursa sac. The synovial fluid is the lubricant in the body which allows structures in the body to glide over one another easily. There are three main types of bursae in the human body namely:

1. Synovial bursae which lie near the synovial membrane of the joints.

2. Adventitious bursae which occurs only after continued shearing or repeated pressure over a bony prominence.

3. Subcutaneous bursae which lie between the skin and bony prominence. They allow frictionless motion of the skin over the bone.

D-They are formed by an extension of the synovial membrane.

Explanation:

These are small sacs, lined by the synovial membrane, located between bones at joints.They are filled with fluids-synovial fluids secreted by the lining synovial membrane.They   therefore reduces frictions at joints between bones,  bones and  muscles, and ligaments .Ensuring  smooth gliding and sliding over one another for friction less movements.  The synovial fluids provided the lubrication for this.

Four  types exists-The synovial, the adventitious, the subcutaneous and sub-muscular

i think it is true in my reasonment ..

i think that d. wind is the answer.   i missed the question when i answered a. currents.