Final answer:
The main job of a tendon is to connect muscle to bone, allowing for transfer of motion and force which enables our bodies to move. Tendon sheaths provide a lubricating fluid that helps tendons move smoothly across joints. Inflammation of tendons, known as tendinitis, can cause pain and affect joint movement.
Step-by-step explanation:
The main job of a tendon is to connect muscle to bone. Tendons are strong bands of dense, regular connective tissue that transfer the tension from muscle contractions to bones, facilitating movement. This connection is vital for skeletal muscles to move the skeleton and for modulating the force and motion transmitted to bones.
Tendons sometimes have tendon sheaths, which are connective tissue sacs that contain lubricating fluid. These sheaths surround the tendons at points where they cross joints, aiding in smooth movement by preventing friction, but it's not their main role. Conditions like tendinitis underscore the importance of tendons, as inflammation in these areas can result from overuse or repetitive motion, leading to pain and impaired movement.