Light micrograph of a joint (amphiarthrosis). Detail of an intervertebral disc, showing the nucleus pulposus. It is composed of an abundant highly hydrated amorphous substance (the vacuolized appearance is an artifact of dehydration of the histological sample) that encompasses chondroid cell cords. Part of the annulus fibrosus is seen on either side of the nucleus pulposus. Above and below are the cartilaginous plates composed of hyaline and fibrous cartilage that line the vertebral bodies.