bone Flashcards
bone
supporting connective tissue
tissue characteristics
-complex organs containing all four tissue types
-extracellular matrix is sturdy and rigid due to deposition of minerals
general functions
-structural support/body framework
-protection of more delicate organs
-movement (attachment site for muscles)
-hemopoiesis
-storage of mineral and energy reserves
hemopoiesis
blood cell production in red bone marrow
storage of mineral and energy reserves
-calcium and phosphate
-lipids stored in yellow marrow
bone classifications
long, short, flat, and irregular
long bones
-longer than wide
-most appendages
short bones
-equal in length and width
-tarsal bone
flat bones
-broad and thin
-cranium bones
irregular bones
-don’t fit in other categories
-unusually shaped
three regions of long bones
diaphysis, epiphysis, and metaphysis
diaphysis
shaft of the bone
epiphysis
-end of bone
-each has two
-proximal and distal
-typically spongy
metaphysis
in between diaphysis and epiphysis
articular cartilage
-at the end of long bones
-function: protection
medullary cavity
-area in center of diaphysis that contains no spongy bone
-contains yellow bone marrow in adult bones
spongy bone
-contains red bone marrow: hemopoiesis
-where new blood cells are produced
endosteum
membrane lining the internal surfaces of the bone
periosteum
covers the external surface of the bone where there is no articular cartilage
blood supply of bones
highly vascularized
innervation
-nerves accompany blood vessels through the nutrient foramen
-innervate (communicate) bone tissue, periosteum
-primarily sensory nerves
types of bone cells
osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts
osteoproenitor cells
cells that will become bone cells
osteoprogenitor cells turn into
osteoblasts
osteoblasts
secrete osteoid, form bone matrix, and build bone tissue
osteocytes
-cells that have become trapped in the bone
-detect stress or strain on the bone
-spider-like
osteoclasts
-dissolve or break down bone
-can deposit calcium into the blood
compact bone
-made up of osteons
-heavy
spongy bone
-made up of trabeculae
-coarse
osteon structure of the compact bone
-also known as a haversian system
-cylindrical structures
-run parallel to the diaphysis
-contain central canals and concentric lamellae
central canal
-open space in the core of the osteon
-contains arteries, veins, and nerves
concentric lamellae
layers of the osteon
canaliculi
spaces where canals within the bone can communicate
perforating canals
-openings perpendicular to the central canal
-allow blood vessels to travel
spongy bone characteristics
-lack osteons: makes bone less strong
-trabeculae contains parallel lamellae
-distributes stress from mechanical forces across framework
ossification
formation of bone connective tissue
two patterns of ossification
intramembranous and endochondral
intramembranous ossification
-has no cartilage
-produces flat bones
-bones develop from mesenchyme membrane
-calcification entraps osteoblasts within lacunae in bone matrix
-osteoblasts become osteocytes
some examples of bones produced by intramembranous ossification
-flat bones of skull
-some facial bones
-mandible
-central portion of clavicle
steps of intramembranous ossification
1) ossification centers form within thickened regions of mesenchyme
2) osteoid undergoes calcification
3) woven bone and surrounding periosteum form
4) lamellar bone replaces woven bone, as compact and spongy bone form
endochondral ossification
-contains cartilage
-formation of most bones of skeleton
-bones develop from hyaline cartilage model
some examples of bones produced by endochondral ossification
-upper/lower limbs
-pelvis
-vertebrae
-ends of clavicles
steps of endochondral ossification
1) fetal hyaline cartilage model develops
2) cartilage calcifies, and a periosteal bone collar forms
3) primary ossification center forms in the diaphysis
4) secondary ossification centers form in the epiphyses
5) bone replaces cartilage, except for articular cartilage and epiphyseal plates
6) epiphyseal plates ossify and form epiphyseal lines
long bone’s growth in length happens
within the bone; interstitial growth
bone’s growth in diameter happens
from the outside; appositional growth
epiphyseal plate
-site of interstitial growth
-consists of five distinct microscopic zones
five microscopic zones
-resting cartilage
-proliferating cartilage
-hypertrophic cartilage
-calcified cartilage
-ossification
