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The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone. The hollow region in the diaphysis is called the medullary cavity which is filled with yellow marrow.

The Central Part of Long Bone: Diphysis

The long bones of the human body are made up of three parts - the epiphysis, the diaphysis, and the metaphysis. The diaphysis is the central shaft-like part of the long bone, which is surrounded by a layer of compact bone tissue. The diaphysis is the longest part of the bone and is responsible for providing support and strength to the bone.

Structure of Diphysis:

The diaphysis of a long bone is made up of several layers of tissue, including:

1. Periosteum: The outer layer of the diaphysis is called periosteum. It is a strong, fibrous membrane that covers the entire bone except for the articular surfaces.

2. Compact bone tissue: The layer beneath the periosteum is made up of compact bone tissue. It is a dense, hard layer of tissue that provides strength and support to the bone.

3. Medullary cavity: The center of the diaphysis is a hollow cavity known as the medullary cavity. It is filled with bone marrow, a soft tissue that produces blood cells.

4. Endosteum: The inner layer of the diaphysis, which lines the medullary cavity, is called the endosteum.

Function of Diphysis:

The diaphysis is responsible for several functions, including:

1. Providing support and strength to the bone.

2. Protecting the bone marrow, which produces blood cells.

3. Serving as a site for muscle attachment.

4. Providing a pathway for blood vessels and nerves to travel through the bone.

Conclusion:

In conclusion, the central part of the long bone is called the diaphysis. It is the longest part of the bone and is responsible for providing support and strength to the bone. The diaphysis is made up of several layers of tissue, including the periosteum, compact bone tissue, medullary cavity, and endosteum.