A&P Ch. 5 Vocab List 1

Axial skeleton

bones that form the longitudinal axis of the body

head, thoracic, tail bone

Appendicular skeleton

bones of the limbs and girdles

Skeletal system

a living framework composed of 206 bones, along with cartilage, ligaments, and tendons

Compact bone

dense; looks smooth and homogeneous

Spongy bone

small needle-like pieces of bone and lots of open space

Long bones

longer than they are wide

Typically have a shaft with heads at both ends

Mostly compact bone

Includes all bones of the limbs, except the wrist and ankle bones

Short bones

generally cube-shaped

Contain mostly spongy bone

Includes bones of the wrist and ankle

“Sesamoid bone”: special type of short bone formed within tendons  (patella)                                

Flat bones

thin, flattened and usually curved

Have 2 thin layers of compact bone sandwiching a layer of spongy bone between them.

Includes most bones of the skull, ribs, and sternum

Irregular bones

bones that do not fit one of the preceding categories

vertebrae, hyoid and hip bones  

Diaphysis

 (shaft); makes up most of the bone’s length and composed of compact bone

Periosteum

 protects the long bone; is a fibrous connective tissue membrane

Perforating

blood vessels or fibers that pierce through deep layers—such as muscle, fascia, or bone membranes—to connect superficial and deep structures

Sharpey’s fibers

secure the periosteum to the bone

Epiphyses

ends of the long bone; each consists of a thin layer of compact bone enclosing an area of spongy bone

Articular cartilage

 covers the external surface of the epiphysis; glassy hyaline cartilage; creates a smooth, slippery surface that decreases friction at joint surfaces

Epiphyseal line

shows where the epiphyseal plate once was

Epiphyseal plate

 seen in a young, growing bone; cause the lengthwise growth of a long bone; the end of puberty causes the plates to be replaced by bone, leaving only the line

Yellow marrow

mainly a storage of fat in the medullary cavity

Medullary cavity

the hollow, central space found within the shaft (diaphysis) of long bones

Red marrow

In infants:  this area forms blood cells

In adults:  red marrow is confined to the cavities of spongy bone of flat bones and the epiphyses of some long bones.

Bone markings

surfaces of bones are not smooth

Shows where tendons, ligaments, muscles, blood vessels and nerves are attached/pass.

Osteocytes

 mature bone cell

Lacunae

 tiny cavities within the matrix

Lamellae

acunae arranged in concentric circles around a central (HAVERSION) canal.

Central (haversian) canals

microscopic, longitudinal channels located at the center of osteons in compact bone that contain blood vessels and nerve fibers to supply living bone cells

vertical canals

Osteon

the fundamental functional and structural unit of compact (cortical) bone

the haversian system

Haversian System

the primary microscopic structural and functional unit of mature compact bone

also known as an osteon

Canaliculi

 tiny canals that radiate outward from the central canals to all lacunae.  This nutrient system form a transportation system that connect all bone cells to the nutrient supply.

Perforating (Volkmann’s) canals

right angles of the communication path

horizontal canals

Ossification

the natural process of bone formation where specialized cells called osteoblasts lay down new bone material

Osteoblasts

bone builders

Osteoclasts

bone breakerdowner

Bone remodeling

osteoclast and osteoblasts work together to reshape, repair, and maintain the structural strength of the skeleton throughout life

Rickets

a childhood metabolic bone disease that causes soft, weak bones due to a failure of growing bone tissue to properly mineralize

Fractures

a broken bone

Reduction

a medical process that restores broken bone fragments or dislocated joints to their exact original position

Hematoma

a localized collection of mostly clotted blood that pools outside of the blood vessels inside an organ, tissue, or body space

Fibrocartilage callus

also called a soft callus

a temporary mix of collagen-producing fibroblasts, cartilage-forming chondroblasts, and blood capillaries that bridges a broken bone during the second phase of fracture healing

Bony callus

a hard, temporary bridge of woven bone that forms around and across a bone fracture site to stabilize the broken pieces during the healing process