anat001 - bone tissues

bone tissue

strong and lightweight tissue

osteology

study of bone tissue and bone disorders

osteoprogenetor cells

• unspecialized

• undergo mitosis and develop into osteoblasts

• found in periosteum, endosteum, and canals that contain blood vessels

• main job is to divide and differentiate into bone-forming cells.

osteoblasts

• cells that form bone but don’t divide

• secrete collagen and other organic bone components

• derived from osteoprogenetor cells

• built the bone matrix around themselves

osteocytes

• mature

• derived from osteoblasts

• don’t divide

• trapped in bone matrix

• don’t secrete matrix material

• maintain cellular activities of bone

• exchange of nutrients and waste with blood

• help maintain the bone

osteoclasts

• believed to develop from circulating monocytes

• settle on bone surface and function in bone reabsorption

• break down bone, take bone awayand are involved in the remodeling process of bone, balancing the activity of osteoblasts.

matrix

contains mineral salts of tricalcium phosphate (hydoxyapatite) and calcium carbonate, with small amounts of magnesium hydroxide, sulfate, and fluoride which make bone hard and strong

calcification

process in which salts are deposited in the framework formed by collagen fibers

compact (dense) bone tissue

• few spaces

• make up bulk of diaphysis

• gives long bones strength

• forms the surface of all bones

• makes up most of the mass of long bones

• forms concentric ring structure

osteon

• the basic structural unit of compact bone

• target-shaped structures made of rings of bone

central (Haversian) canal

• a hole at the center of the osteon

• contains blood vessels, lymphatic vessels and nerves

concentric lamellae

• rings of bone around the central canal

• make up the osteon

• between the lamellae are small spaces called lacunae which house osteocytesand provide structural support.

canaliculi

• small channels which radiate away from the lacunae

• filled with extracellular fluid and processes from osteocytes

interstitial lamellae

arches of bone that fill up the spaces between the osteons

circumferential lamellae

• arches of bone around the surface of the bones

• make the bone surface smooth

perforating canals

• tubes in the sides of the bones that allow blood vessels, lymphatic vessels and nerves to reach the central canals of the osteons

• connect all the central canals

spongy bone tissue

• doesn’t contain osteons

• made of irregular lattice of bone plates called trabeculae

• found in the center of long bones and in the mass of anything that’s not a long bone

long bones

• greater length than width

• curved for strength

• mostly made of compact bone with some spongy bone

• ex. thigh, leg, arm, forearm, finger, and toes

short bones

• cube-shaped

• made of spongy bone except at the surface where there is a thin layer of compact bone

• ex. wrist and ankle bones

flat bones

• thin

• composed of 2 parallel plates of compact bone enclosing a layer of spongy bone

• provide protection and places for muscle attachment

• ex. cranial bones, sternum, ribs

irregular bones

• complex shape

• vary in amount of spongy and compact bone tissue

• ex. vertebrae

sutural bones

• small bones found in the sutures of certain cranial bones

• vary in number between people, not all people have them

sesamoid bones

• small bones warped in tendons where pressure develops

• helps diminish stress on a joint

  • depends on what you do in life

diaphysis

main shaft of a long bone

epiphysis

• ends of a long bone

• form joints 

metaphysis

• in mature long bone where epiphysis meets diaphysis

• in growing bone

• it contains epiphyseal plate which hardens when you reach your full height and becomes epiphyseal line

articular cartilage

thin layer of hyaline cartilage where the bone articulates with another bone

periosteum

• membrane around the surface of bone not covered by articular cartilage

• has 2 layers: fibrous layer and inner osteogenic layer

fibrous layer

made of dense irregular connective tissue, contains blood vessels, lymph vessels and nerves

inner osteogenic layer

has elastic fibers, blood vessels and various types of bone cells

medullary

• marrow cavity

• space in diaphysis filled with yellow bone marrow

• present in all bone types

• hollow area inside the bone

endosteum

• membrane that lines the medullary

• contains osteoprogenetor cells and osteoclasts

• present in all bone types