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hyaline cartilage

provide support with flexibility and resilience; the most abundant skeletal cartilages

elastic cartilages

contain more stretchy elastic fibers and so are better able to stand up to repeated bending

fibrocartilages

highly compressible with great tensile strength

axial skeleton

forms the long axis of the body and includes the bones of the skull, vertebral column, and rib cage

appendicular skeleton

consists of the bones of the upper and lower limbs and the girdles that attach the limbs to the axial skeleton

sesamoid bones

special type of short bone that form in a tendon

important functions of bones

support, protection, movement, mineral and growth factor storage, blood cell formation, triglyceride storage

medullary cavity

cavity within the shaft of the long bones filled with bone marrow

epiphyseal line

The cartilage present at the junction of the diaphysis and epiphyses; a remnant of the epiphyseal plate.

metaphysis

flared portion of the bone where the diaphysis and epiphysis meet

periosteum

covers the external surface of the entire bone except the joint surfaces

Sharpey's fibers

tufts of collagen fibers that extend from its fibrous layer into the bone matrix; secure the periosteum to the underlying bone

bone markings

sites of muscle, ligament, and tendon attachment, as joint surfaces, or as conduits for blood vessels and nerves

osteogenic cells

mitotically active stem cells found in the membranous periosteum and endosteum

osteoblasts

bone forming cells that secrete the bone matrix

osteoclasts

giant multinucleate cells located at sites of bone resorption

osteon

structural unit of compact bone

lamella

matrix tube; "little plate"

Haversian canal

containing small blood vessels and nerve fibers that serve the osteon's cells

Volkmann's canals

lie at right angles to the long axis of the bone; connect the blood and nerve supply of the periosteum to those in the central canals and the medullary cavity

canaliculi

connect lacunae to each other and to the central canal

trabeculae

align precisely along lines of stress and help the bone resist stress; contain irregularly arranged lamellae and osteocytes interconnected by canliculi

osteoid

organic part of matrix

hydroxyapatites

mineral salts; largely calcium phosphates present as tiny, tightly packed, needle like crystals in and around collagen fibers in the extracellular matix

Wolff's Law

states that a bone grows or remodels in response to the demands placed on it

repair of a bone fracture

a hematoma forms, fibrocartilaginous callus forms, bony callus forms, bone remodeling occurs

osteomalacia

"soft bones"; includes a number of disorders in which the bones are poorly mineralized

skull

most complex bony structure; formed by cranial and facial bones

functions of the facial bones

form the framework of face, contain cavities for the special sense organs of sight taste and smell, provide openings for air and food passage, secure the teeth, anchor the facial muscle of expression

function of cranial bones

enclose and protect the fragile brain and furnish attachment sites for head and neck muscles

vertebral column

rigid supporting rod

centrum

body of vertebrae

transverse process

extends laterally from each side of the vertebral arch

atlas

C1; no body and no spinous process; say yes

axis

C2; has a body and other typical vertebral processes

sacrum

articulates superiorly with L5 and inferiorly with the coccyx; laterally, the sacrum articulates with the two hip bones to form the pelvis

coccyx

tailbone; small triangular bone

thoracic cage

bony thorax; forms a protective cage around the vital organs of the thoracic cavity, supports the shoulder girdles and upper limbs, provides attachment points for many muscles

appendicular skeleton

bones of the limbs and their girdles

pectoral girdle

consists of the clavicle anteriorly and the scapula posteriorly; attaches the upper limbs to the axial skeleton and provide attachment points for many of the muscles that move upper limbs

humerus

the largest, longest bone of the upper limb; articulates with the scapula at the shoulder and with the radius and ulna at the elbow

forearm

two parallel long bones, radius and ulna; antebrachium

acetabulum

"vinegar cup"

fovea capitis

"pit of the head"

medial longitudinal arch

curves well above the ground; talus is the keystone of this arch

lateral longitudinal arch

elevates the lateral part of the foot just enough to redistribute some of the weight to the calcaneus and the head of the fifth metatarsal

transverse arch

runs obliquely from one side of the foot to the other, following the line of the joints between the tarsals and metatarsals

fontanelles

allow an infant's head to be compressed slightly during birth, and accommodate brain growth in the fetus and infant

articulations

sites where two or more bones meet

fundamental functions of joints

give skeleton mobility, hold it together, and sometimes play a protective role

synarthroses

immovable joints

amphiarthroses

slightly movable joints

diarthroses

freely movable joints

fibrous joints

bones are joined by fibrous tissue; no joint cavity is present

sutures

only between bones of the skull; allow skull to expand as the brain grows during youth

synostoses

fibrous tissue tat ossifies and the skull bones fuse into a single unit

syndesmoses

bones that connected exclusively by ligaments

gomphosis

pig in socket fibrous joint

cartilaginous joints

articulating bones that are united by cartilage; lack a joint cavity

chondrosis

"junction of cartilage"; where a bar or plate of hyaline cartilage unites the bone

symphysis

where fibrocartilage unites the bone; "growing together"

synovial joints

joints in which articulating bones are separated by a fluid containing joint cavity; freely movable diathroses

six distinguishing features of synovial joints

articular cartilage, joint cavity, articular capsule, synovial fluid, reinforcing ligaments, nerves and blood vessels

bursae

flattened fibrous sacs lined with synovial membrane and containing a thin flim of synovial fluid

tendon sheath

an elongated bursa that wraps completely around the tendon subjected to friction

origin

attachment to the immovable bone

insertion

attachment to the movable bone

gliding

one flat bone surface glides or slips over another without appreciable angulation or rotation

angular movements

increase or decrease the angle between two bones; may occur in any plane of the body and include flexion, extension, hyperextension, abduction, adduction, and circumduction

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