Musculoskeletal Physiology - Anatomy

The endosteum is the layer that is found deep to all layers. It is found in the inner lining of the bone. Meanwhile, the periosteum is the most superficial layer of the bone which compromises the outer covering of bones.

Osteoblasts will lay down bone matrix around previously formed bone tissue. This forms concentric rings of bone tissue referred to as lamellae.

Lacunae are small gaps in the hydroxyapatite matrix that house the osteocytes. Trabeculae are thin bony structures that span and branch within the region of spongy bone. Canaliculi are small channels between lacunae that allow for cellular nourishment and communication. The epiphyses are the ends of the bone (as opposed to the diaphysis, or bone shaft).

Osteoblasts are differentiated non-dividing cells that secrete osteoid, an organic matrix material, that becomes mineralized forming bone. These are the cells primarily responsible for building bone.

Osteocytes are osteoblasts that become trapped in lacunae by bony matrix. These cells still maintain the bone environment, but do not actively build or modify bone a significant amount.

Osteoclasts resorb bone by breaking down the crystalline matrix.

Deposition of the calcium phosphate salt hydroxyapatite leads to mineralization of the bony matrix.

A synarthrosis is a type of joint that permits little or no movement. Syndesmoses, synostoses, and symphyses are all examples of synarthroses. Syndesmoses are joined by an interosseous ligament. Joints between carpals and tarsals are mostly syndesmoses. Synostoses is a joint formed from the fusion of two bones, generally in an atypical fashion. Symphyses can be synarthroses or amphiarthorses and are characterized by a fibrocartilage band between bones, such as in the pubic symphysis.

A diarthrosis, also known as a synovial joint, is the most common joint type in humans and allows free bone movement. The knee and elbow are examples of a diarthroses or synovial joints.

The joints, or articulations, of the body can be classified according to several different criteria. They can be named for their structure, type of motion, or range of motion.

Synovial joints are determined by the joint structure. All synovial joints are housed within a joint capsule and contain synovial fluid. Joints between long bones are almost always synovial joints.

Syndesmoses are defined by their range of motion, and have very small, if any, motility. Syndesmoses are joined by interosseous ligaments, such as those between the carpals of the wrist.

Saddle joints are defined the type of motion allowed at the joint. Saddle joints are biaxial, allowing flexion, extension, adduction, and abduction, but no axial rotation. The pollical (thumb) joint is a saddle joint. While a "swinging joint" would seem to indicate a joint defined by its type of motion, no such joint exists in anatomical terms.

Metaphysis: has the greatest metabolic activity, and contains the epiphyseal plate, which is replaced by the epiphyseal line

Diaphysis: mechanical support, site of bone marrow and muscle attachments

Apophysis: functions as a site for attachments of ligaments and tendons

Epiphysis: at the end of long bones

Periosteum: covers the diaphysis and parts of metaphysis.

The medullary cavity is the bone marrow cavity contains red and/or yellow bone marrow; red bone marrow is the site of hematopoiesis. The end of a long bone is known as the epiphysis. Compact bone (cortical bone) is the dense outer layer of bone. The diaphysis is the shaft of a long bone.

There are three main joint categories: synovial, fibrous, and cartilaginous. Synovial joints have the largest range of movement, and are characterized by the presence of articular cartilage and synovial fluid. Fibrous joints lack cartilage and allow for little to no movement. Cartilaginous joints are formed by bands of cartilage between bones, and generally have some limited movement. The shoulder is a synovial joint, the sutures of the skull are fibrous joints, and the intervertebral joints are cartilaginous joints.

Diarthrosis is used to describe joints with wide ranges of movement. Amphiarthrosis describes joints with limited movement, while synarthrosis describes joints with no movement. Almost all fibrous joints are synarthrotic.

Your fingers are able to flex and extend. This type of motion is bidirectional, but along only one axis. This type of joint is called a hinge joint, at which you are able to flex and extend along an axis, with no side to side motion.

The nucleus pulposus is a gelatinous, spongy material located in the core of the vertebral disk. This material responds directly to the pressures of the spinal joints, allowing for twisting, compressing, and stretching forces acting upon the spinal joints and vertebrae. This material can become less resilient with age, but generally does not disintegrate or die as other structures do.

When the rhomboids contract, they pull on the scapula, causing the inferior angle of the scapula to swing up toward the spine. This causes the glenoid fossa to orient downward. Thus, the scapula is downwardly rotated by the rhomboids at the scapulocostal joint.

When the psoas minor contracts to flex the lower trunk relative to the upper trunk, this posterior tilting of the pelvis occurs at the lumbosacral joint.

The correct answer is red marrow.

Hematopoiesis is the formation of blood cells, which is a function of red marrow. Red marrow forms red blood cells, white blood cells and blood platelets. The process beings with a stem cell that proliferates (reproduces rapidly), differentiates (becomes a specialized cell) and replicates (duplicates).

The other choices are all parts of bones, but have different functions/characteristics besides hematopoiesis. While red marrow contains the red and white blood cells and blood platelets, yellow marrow consists of mostly fat cells. Compact bones are hard and contain closely packed osteons that form a solid mass. The periosteum is the connective tissue covering the surface of a bone. Spongy bones are less dense than compact bone and are lighter than compact bones. It contains plates (trabeculae) of bone and cavities that contain the red marrow.

Osteoblasts will lay down bone matrix around previously formed bone tissue. This forms concentric rings of bone tissue referred to as lamellae.

Lacunae are small gaps in the hydroxyapatite matrix that house the osteocytes. Trabeculae are thin bony structures that span and branch within the region of spongy bone. Canaliculi are small channels between lacunae that allow for cellular nourishment and communication. The epiphyses are the ends of the bone (as opposed to the diaphysis, or bone shaft).

Osteoblasts are differentiated non-dividing cells that secrete osteoid, an organic matrix material, that becomes mineralized forming bone. These are the cells primarily responsible for building bone.

Osteocytes are osteoblasts that become trapped in lacunae by bony matrix. These cells still maintain the bone environment, but do not actively build or modify bone a significant amount.

Osteoclasts resorb bone by breaking down the crystalline matrix.

Deposition of the calcium phosphate salt hydroxyapatite leads to mineralization of the bony matrix.

A synarthrosis is a type of joint that permits little or no movement. Syndesmoses, synostoses, and symphyses are all examples of synarthroses. Syndesmoses are joined by an interosseous ligament. Joints between carpals and tarsals are mostly syndesmoses. Synostoses is a joint formed from the fusion of two bones, generally in an atypical fashion. Symphyses can be synarthroses or amphiarthorses and are characterized by a fibrocartilage band between bones, such as in the pubic symphysis.

A diarthrosis, also known as a synovial joint, is the most common joint type in humans and allows free bone movement. The knee and elbow are examples of a diarthroses or synovial joints.

The joints, or articulations, of the body can be classified according to several different criteria. They can be named for their structure, type of motion, or range of motion.

Synovial joints are determined by the joint structure. All synovial joints are housed within a joint capsule and contain synovial fluid. Joints between long bones are almost always synovial joints.

Syndesmoses are defined by their range of motion, and have very small, if any, motility. Syndesmoses are joined by interosseous ligaments, such as those between the carpals of the wrist.

Saddle joints are defined the type of motion allowed at the joint. Saddle joints are biaxial, allowing flexion, extension, adduction, and abduction, but no axial rotation. The pollical (thumb) joint is a saddle joint. While a "swinging joint" would seem to indicate a joint defined by its type of motion, no such joint exists in anatomical terms.

Metaphysis: has the greatest metabolic activity, and contains the epiphyseal plate, which is replaced by the epiphyseal line

Diaphysis: mechanical support, site of bone marrow and muscle attachments

Apophysis: functions as a site for attachments of ligaments and tendons

Epiphysis: at the end of long bones

Periosteum: covers the diaphysis and parts of metaphysis.

The medullary cavity is the bone marrow cavity contains red and/or yellow bone marrow; red bone marrow is the site of hematopoiesis. The end of a long bone is known as the epiphysis. Compact bone (cortical bone) is the dense outer layer of bone. The diaphysis is the shaft of a long bone.