Final answer:
The Golgi tendon organ is the specialized structure in tendons that senses muscle tension in skeletal muscles, different from muscle spindles which detect muscle stretch.
Step-by-step explanation:
The specialized structure within the tendons of skeletal muscles that senses muscle tension is the Golgi tendon organ. Unlike the muscle spindles, which are stretch receptors that detect the lengthening of muscles, the Golgi tendon organ is focused on sensing the tension that muscles exert on tendons during contraction. This sensation helps prevent muscle damage from excessive force by initiating a reflex that relaxes the muscle when tension is too high.
Skeletal muscle structure includes several components such as tendons, myofibrils, and sarcomeres. Myofibrils contain sarcomeres composed of the proteins actin and myosin, both crucial for muscle contraction. The whole muscle structure is surrounded by connective tissue membranes, and these muscles are connected to the skeletal system through tendons.