Artifact Two

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Skeletal Physiolo

Short bones: carpals and tarsals (bones in your fingers and toes)

Flat bones: Calvarium (skull bone), sternum, or scapula

Long bones: femur, tibia and fibula (all leg bones) or humerus, radius and ulna (arm bones)

Irregular bones: bones that can't fit into the above categories: vertebrae (spine), hyoid, maxilla and mandible (jaw), and the bones of your sinuses: ethmoid, zygomatic, and sphenoid (1)

Diaphysis: main or midsection/ shaft of a long bone. Made up of cortical bone and usually contains bone marrow and adipose tissue.

Epiphyses: End of a long bone that is originally separated from the main bone. (1)

Articular Cartilage: smooth, white tissue that covers the ends of bones in joints. (1)

Periosteum: a specialized connective tissue covering all bones and having bone-forming potentialities. (1)

FOUR TYPES OF

BONES:

Six Major structures of a

typical long bone:

Artifact Two

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Skeletal Physiolo

Medullary (marrow) Cavity: space in a bone where a soft, flexible substance called marrow is stored. (1)

Endosteum: thin layer of cells lining the medullary cavity of a bone. (1)

Composition of bone Matrix: The release of these growth factors from the bone matrix could cause the proliferation of osteoblast precursors. (1)

Inorganic matrix: structural strength (1)

Measuring bone mineral density: Proxy measurement for bone strength. (1)

Organic Matrix: elements of a bone are primarily collagen. It

allows bones to flex. (1)

Osteoblasts- are small cells that synthesize and secrete a specialized organic matrix, called Osteoid, that is an important part of the ground substance of bone.

Major constituents of bone as

a tissue:

TYPES OF BONE CELLS:

Osteoclasts- are giant Multinucleate cells that are responsible for the active erosion of bone minerals.

Osteocytes- Are mature, nondividing osteoblasts that have become surrounded by matrix and now lie within lacunae. (1)

© (6) © (7)

The osteon or Haversian system is the fundamental functional unit of

compact bone. Osteons are roughly cylindrical structures

that are typically several millimeters long and around

0.2mm in diameter. They are present in many bones of most mammals and some bird, reptile and

amphibian species. (1)

Haversian

System

© (5)

Lacunae Containing Osteocytes- (Latin for the Lakes) Small Spaces containing Tissue fluid in which bone cells lie imprisoned between the hard layers of the lamellae.

Lamellae-Concentric, Cylinder-shaped layers of calcified matrix

Canaliculi- Ultrasmall canals radiating in all directions from the Lacunae and Connecting them to each other and into a larger canal, The Haversian canal.

Haversian Canal- Extends lengthwise through the center of each Haversian system; contains blood vessels, Lymphatic Vessels, and nerves from the Haversian Canal; nutrients and oxygen move through canaliculi to the Lacunae and their bone cells--- a short distance of about 0.1 mm or less.

Volkmann’s canal and communicating canals that contain nerves and vessels that carry blood and lymph from the exterior surface of the bone to the Osteons.

Osteons- Compact bones that contain many cylinder-shaped structural units.

1.Support – bones act as the framework for our body, creating the shape of our skeleton

2.Protection – our bones help protect our vital organs, like the rib cage protects our lungs and heart

3.Movement – Our muscles are attached to our bones which allow us to move at the joints

4.Mineral Storage – Bones store many minerals, such as calcium and phosphorus. Homeostasis blood calcium concentration is vital to living, it has to be equal levels in the bone and the blood (1.)

5.Hematopoiesis (blood cell formation) – a vital process carried out by red bone marrow (1.)

Intramembranous ossification takes place in a connective tissue membrane. It usually involves the flat bones while endochondral ossification usually deals with long bones.

Homeostatic Functions of Bones

Ossification

Intramembranous ossification deals with the fetus. Ground substance and the collagenous fiber make the organic bone matrix. Calcification of the matrix forms and continues until the trabeculae appear and form spongy bone. (1)

Endochondral ossification is from cartilage models with bone formation spreading from the center to the ends. The bone continues to grow through primary ossification center and secondary ossification center. An epiphyseal plate remains between the epiphysis and diaphysis. (1)

A bone fracture tears and destroys blood vessels that carry nutrients to osteocytes, which is what initiates the repair sequence. The fracture itself is the first step in the bone repair process. The next step is the formation of a fracture hematoma. Then it is the formation of internal and external callus, which bind the broken fragment together which stabilizes the wound and allows the healing process to procede. And after that the bone remodeling is complete. (1)

Ossification

Repair of

Bone

Fracture

s

CARTILAGE

Hyaline Cartilage - provides firm support with some pliability. It covers the ends of the long bones as articular cartilage , providing springy pads that absorb compression at joints . Has resilient cushioning properties ; resists compressive stress. Supports the tips of the nose , connects the ribs to the sternum , and supports most of the respiratory system passages. The skeletal hyaline comes during childhood as the epiphyseal plates , provide for continued growth in length. Covers the ends of long bones in joint cavities ; forms costal cartilages of ribs , nose , trachea , and larynx. (1)

Elastic Cartilage - Found where strength and exceptional stretch ability are needed. Elastic cartilage forms the skeletons of the external ear and the epiglottis. Maintain the shape of a structure while allowing great flexibility.

Similar to hyaline but more elastic fibers in matrix. (1)

Fibrocartilage- Compressible and resists tension well , found where strong support and the ability to with strand heavy pressure are required. EX: the spongy cartilage of the knee , Intervertebral discs Strength with the ability to absorb compressive shock.

Less firm than the hyaline; thick collagen fibers predominate. (1)

CARTILAGE

Interstitial Growth: The cartilage cells within the substance of the tissue mass divide and begin to secrete additional matrix. Internal division of chondrocytes is possible because of the soft, pliable nature of cartilage tissue. This type of growth is mostly seen during childhood and early adolescence, when the majority of the cartilage

is still soft and capable of expansion from within (1)

Appositional Growth: This occurs when chondrocytes in the deep

layer of the perichondrium begin to divide and secrete additional matrix. The new matrix is then deposited on the surface of the cartilage, causing it to increase in size. This type of growth is unusual in early childhood but, once it starts it continues beyond adolescence and throughout an individual’s life. (1)

Growth of

Cartilag

e

Joints are classified into 3 major categories using a structural or a functional scheme. If a structural classification is employed, joints are named according to the type of connective tissue that joins the bones together, (fibrous and cartilaginous) or by the presence of a fluid-filled joint capsule. (synovial joints) (1)

If a functional classification scheme is used, joints are divided into three classes according to the degree of movement they permit. (synarthroses, amphiarthroses, and diarthroses) (Immovable, slightly movable and freely moveable) (1)

Fibrous joints are synarthroses. The articulating surfaces of these joints fit

closely together.

The three types of fibrous joints are:

Syndesmoses- Joints on which fibrous bands connect two bones

Sutures- Found only in the skull, teeth like projections jut out from adjacent bones and interlock with each other with only a thin layer of fibrous tissue between them. (1)

Classification of joint

s

Gomphoses: unique joints that occur between the root of a tooth and the alveolar process of the mandible and maxilla. (1)

Cartilaginous Joints are amphiarthroses: The bones that articulate to form a cartilaginous joint are joined together by either hyaline cartilage or fibrocartilage. There are two types of these

Sychondroses: Joints that are characterized by the presence hyaline cartilage between articulating bones

Symphyses: a joint in which a pad or disk of fibrocartilage connects two bones (1)

They are the body’s most moveable, numerous and the most anatomically complex joints.

Seven types of structures for synovial joins

joint capsules, synovial membrane, articular cartilage, joint cavity, menisci (articular disks), ligaments and bursea (1)

Synovial joints are divided into three main groups: Uniaxial, biaxial, and multiaxial

Synovial

joints

Uniaxial joints: Synovial Joints that permit movement around only one axis and in only one plane. EX: Hinge Joints and Pivot Joints

Biaxial joints: Diaphroses that permit movement around two perpendicular axes in two perpendicular planes EX: Saddle Joints and Condyloid Joints

Multiaxial Joints: Joints that permit movement around three or more axes and in three or more planes EX: Ball and Socket joints and Gliding joints (1)

The 2 functions that have gone awry that cause the need for a bone marrow transplant and osteoporosis are low bone mineral density due to not enough calcification. The normal process should be the calcification of highly specialized crystals of calcium and phosphate. A bone marrow transplant is performed if someone has damaged bone marrow, normally red blood marrow produces red blood cells and yellow bone marrow is saturated in fat not involved in blood cell production but can change to red bone marrow

if needed. (1)

Questions

A fracture in the epiphyseal plate can cause problems in kids because their bones have not finished growing, the epiphyseal plate is there as a barrier between the shaft and end of the bone and if it gets fractured it can cause problems in the ossification process.

As you get older your bones start to weaken and you start to have bone loss. With this bone loss comes changes in your skeletal frame, you get shorter and can have a humped back. You also have remodeling of in compact bone which involves new haverian systems. (1)