Name: inside a long bone
Uploaded: 2025-10-23T11:47:05.000Z
Duration: 1 min 55 s
Channel: JoVE

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Next Generation Science Standards

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Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-2

Bone Structure

Within the skeletal system the structure of a bone, or osseous tissue, can be exemplified in a long bone like the femur where there are two types of osseous tissue, cortical and cancellous.

Covering the cortical, or compact bone, is a membrane called the periosteum, which contains connective tissue, capillaries, and nerves. The neighboring outer solid layer found along the diaphysis, the shaft, forms a dense protective shell around the medullary canal, the cavity that stores yellow bone marrow, composed primarily of fat cells. This space is also covered in a thin lining, the endosteum, in which bone growth, remodeling, and repair occur.

Within the compact layer are osteons, structural units arranged in concentric rings called lamellae that contain osteoblasts, cells critical for bone formation and growth. These cells eventually mature into osteocytes in the hollow space, the lacuna.

Through the center of each osteon runs the Haversian canal, which contains more blood and lymphatic vessels as well as nerve fibers. Towards the rounded ends of the long bone, the epiphyses, is the second type of osseous tissue known as cancellous or spongy bone.

This inner layer is composed of a honeycomb-like network of trabeculae, grouped arrangements that form along the lines of stress points to maximize strength with minimal mass. Between each trabecular pore is red bone marrow, which contains hematopoietic stem cells that form into red and white blood cells and platelets that ultimately enter into the circulatory and lymphatic systems.

bone structure

Within the skeletal system, the structure of a bone, or osseous tissue, can be exemplified in a long bone, like the femur, where there are two types of osseous tissue: cortical and cancellous.

<h4>Cortical Bone</h4>

Covering the cortical, or compact bone, is a membrane called the periosteum, which contains connective tissue, capillaries, and nerves. The outer, solid layer&#8212;found along the diaphysis, the shaft&#8212;forms a dense protective shell around the medullary canal&#8212;the cavity that stores yellow bone marrow, composed primarily of fat cells. This space is also covered in a thin lining&#8212;the endosteum in which bone growth, remodeling, and repair occur.

Within the dense layer of cortical bone are osteons&#8212;structural units, arranged in concentric rings called lamellae, that contain osteoblasts&#8212;cells critical for bone formation and growth. These cells eventually mature into osteocytes in the hollow space, the lacuna. Through the center of each osteon runs the Haversian canal, which contains more blood and lymphatic vessels, as well as nerve fibers.

<h4>Cancellous Bone</h4>

Towards the rounded ends of the long bone, the epiphyses is the second type of osseous tissue, known as the cancellous, or spongy, bone. This inner layer is composed of a honeycomb-like network of trabeculae&#8212;grouped arrangements that form along the lines of stress points to maximize strength with minimal mass. Between each trabecular pore is red bone marrow, which contains hematopoietic stem cells that form into red and white blood cells and platelets that ultimately enter the circulatory and lymphatic systems.

Within the skeletal system, the structure of a bone, or osseous tissue, can be exemplified in a long bone, like the femur, where there are two types of ...

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Musculoskeletal System

KEY TERMS AND CONCEPTS

inside a long bone

Inside a long bone, osseous tissue is organized into two main types: cortical bone and cancellous bone. A femur is a clear example of this structure. The bone also includes outer coverings and inner spaces that support growth, repair, and blood cell production.

Cortical bone, also called compact bone, forms the dense outer layer along the diaphysis, or shaft. It is covered by the periosteum, a membrane with connective tissue, capillaries, and nerves. Beneath the cortical layer is the medullary canal, a cavity that stores yellow bone marrow, which is made mainly of fat cells. This space is lined by the endosteum, where bone growth, remodeling, and repair take place.

Within cortical bone are osteons, the structural units of compact bone. Each osteon is arranged in concentric rings called lamellae and contains osteoblasts, which are important for bone formation and growth. As these cells mature, they become osteocytes in small spaces called lacunae. A Haversian canal runs through the center of each osteon and carries blood and lymphatic vessels, along with nerve fibers.

Toward the rounded ends of the long bone, or epiphyses, is cancellous bone, also called spongy bone. This inner layer has a honeycomb-like network of trabeculae that line up along stress points to give strength with less mass. The spaces between the trabeculae contain red bone marrow, which has hematopoietic stem cells that develop into red and white blood cells and platelets before entering the circulatory and lymphatic systems.

Inside a Long Bone

what is the skeletal system?

Human Skeleton: Bones, Cells, and Disease

The human skeleton is a living framework made of 206 bones in adults. Bones connect with cartilage, tendons, and ligaments. This system gives the body support, protects organs, and helps with movement and locomotion. The skeleton has two main parts: the axial skeleton and the appendicular skeleton. The axial skeleton has 80 bones and includes the skull, the vertebral column, and the rib cage. The cranium, or upper skull, has eight bones that enclose the brain, while the lower part of the skull...

Inside a long bone, osseous tissue is organized into two main types: cortical bone and cancellous bone. A femur is a clear example of this structure. The bone also includes outer coverings and inner spaces that support growth, repair, and blood cell production. Cortical bone, also called compact bone, forms the dense outer layer along the diaphysis, or shaft. It is covered by the periosteum, a membrane with connective tissue, capillaries, and nerves. Beneath the cortical layer is the medullary...

joints

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Joints are the places where adjacent bones connect. They are also called articulations or articular surfaces. Joints help the body move and stay stable. Joints can be classified by structure or by function. Structural classification depends on the material that forms the joint and whether there is a space between the bones. By structure, joints are fibrous, cartilaginous, or synovial. Fibrous joints are connected by fibrous tissue and have no cavity between the bones. Because of this, they do...

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Bone turnover is a continuous process in which old bone is broken down and new bone is built. Osteoclasts carry out bone resorption, and osteoblasts carry out bone formation. In adults, this balanced cycle helps maintain bone mass and calcium homeostasis. Mechanical stress can also stimulate turnover as part of normal maintenance and repair. Parathyroid hormone, or PTH, helps control blood calcium levels by increasing bone resorption when calcium is low. It is released from the parathyroid...

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Skeletal muscle moves the body by pulling on bones through tendons. Tendons are the connective tissue that attaches skeletal muscle to bones. When skeletal muscles contract, they create voluntary movement. Skeletal muscle is wrapped in layers of connective tissue. The outer layer is the epimysium, which helps protect the muscle. Beneath it, the perimysium surrounds and groups fasciculi, which are bundles of skeletal muscle cells called myocytes. These cells are also called skeletal muscle...

classification of skeletal muscle fibers

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muscle contraction

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cross-bridge cycle

Calcium Control in Muscle Contraction

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motor units

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key terms and concepts

Explore the parts of a long bone, including cortical bone, cancellous bone, osteons, marrow, and the cells that support growth and blood cell formation.

Inside a Long Bone | JoVE K12

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HS-LS1-3

Inside a Long Bone

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