Representing different component of actin filament

Each middle ear contains three tiny bones, named, i.e., malleus, incus and stapes which are collectively called as ear ossicles.

Difference between the matrix of bones and cartilage

Matrix of Bones	Matrix of Cartilage
Matrix of bones has an inflexible material, the ossein.	Matrix of cartilage has a flexible material, the chondrin.
Matrix of bones contains calcium salts.	Calcium salts may or may not be present in matrix.

Myasthenia gravis is an autoimmune disorder of skeletal muscle, affecting neuromuscular junction, that leads to fatigue, weakening and paralysis of the skeletal muscle.

The presence of synovial fluid, between articulating surface of the two bones enclosed within synovial cavity of synovial joints to makes our joints to function without grinding noise and pain.