The long, tubular shaft of a long bone is called
A epiphysis
B tuberosity
C diaphysis
D hypophysis
The correct answer and explanation is:
The correct answer is C. diaphysis.
The diaphysis is the long, tubular shaft of a long bone. It serves as the main structural component and provides support to the bone. The diaphysis is composed mainly of compact bone, which is dense and provides strength. The central part of the diaphysis contains the medullary cavity, also known as the marrow cavity, which houses bone marrow. This bone marrow is crucial for the production of blood cells, including red blood cells, white blood cells, and platelets.
The ends of the long bone are called the epiphyses (option A). The epiphysis is the region where the bone articulates with other bones at a joint. The epiphysis is primarily composed of spongy bone and is covered by a layer of hyaline cartilage, which reduces friction and acts as a cushion at the joint.
The tuberosity (option B) refers to a raised area or bump on a bone that typically serves as an attachment point for muscles or tendons. Tuberosities are not specific to long bones but can be found on various bones throughout the body.
The hypophysis (option D), also known as the pituitary gland, is not related to bone anatomy. It is a small gland located at the base of the brain and is responsible for regulating various hormonal functions in the body.
In summary, the diaphysis is the central shaft of a long bone, and its main function is to provide structural support, house bone marrow, and serve as the attachment site for muscles. The epiphysis, located at the ends of the bone, is involved in joint movement and is structured differently from the diaphysis.