bone composition and structures

osetology

the study of bone

osetitis

inflammation of bone tissue

osseous

connective tissue with a hardened matrix

osetogenesis/ossification

formation of bone

osetoid

organic matrix before calcium added

support, protection, movement, mineral storage/balance, and blood formation

what are all of the functions of the skeletal system?

provides hard framework

how does the skeletal system support the body?

encloses the internal organs (viscera)

how does the skeletal system protect the body?

skeletal muscles attach to bones

how does the skeletal system help the body move?

reservoir

the skeletal system acts as a ________ for minerals, allowing for storage and balance

hemopoietic

the skeletal system is __________, meaning that it has the ability to form blood

long bones

bones that are longer than they are wide; consist of a shaft with two enlarged ends

compact bone with a spongy bone middle

how are long bones composed?

appendicular skeleton

which skeleton consisits of only long bones (axial or appendicular)?

short bones

bones that are wider than they are long; vary in size and number in different individuals

\*mostly composed of spongy bone

flat bones

bones that are thin, curved plates and consist mostly on spongy bone

carpals and tarsals

what are some examples of short bones?

cranial bones, sternum, ribs, scapula

what are some examples of flat bones?

irregular bones

bones that fit no other bone description; composed mostly of spongy bone

EX: vertebrae and ear bones

compact bones

bones that are dense, smooth, and homogeneous

spongy bones

bones that are small with a large amount of open air spaces

osteogenic

stem cells that derive from embryonic mesenchymal (mesoderm) layer

\-located in the endosteum and inner layer of the periosteum and

\-multiply continuously

osteoblast

bone forming cells that are located in a single layer on the bone surface under the endosteum and periosteum

\-non-mitotic

\-synthesize organic material of bone matrix

osteocyte

mature bone cells (former osteoblasts confined to lucanae)

\-have a ruffled border (extension of plasma membrane that faces bone surface)

\-howship lacunae (resorption bay) pits within bone where osteoclast reside/works

bone organic matrix

bone matrix that is synthesized by osteoblast; includes collagen, GAGs, glycoproetins, and proteiglycans

bone flexability and tensile strength

what is the organic matrix of bone responsible for?

bone inorganic matrix

composed of hydroxapitite (mineral salts); accounts for the exceptional hardness of bone (resists compression)

persist long after death

what do bone salts in the inorganic matrix allow the bone to do?

red bone marrow

bone marrow that is hemopoietic and produces blood cells

\*aka Myeloid

yellow bone marrow

bone marrow that no longer produces blood and can revert back to red bone marrow in cases of exterme anemia

\*aka fatty marrow

diaphysis (shaft)

this is the long axis of a bone; a thick collar of compact bone that surrounds a central cavity

medullary cavity (marrow cavity)

this is the central cavity of the bone that contains yellow marrow in adults

epiphysis (bone ends)

compact bone forms the exterior and the interior is composed of spongy bone; contains articular (hyaline) cartilage at the joint surface to absorb stress

nutrient foramen

openings in bones for blood vessels

epiphyseal line

part of bone that is the remnant of the epiphyseal plate/growth plate, region of hyaline cartilage that grows during childhood

sharpey’s fibers

collagen fibers that connect the periosteum with the bone matrix

diploe

spongy bone sandwitched between 2 layers of compact bone

\*\*only found in flat bones

periosteum

outer surface of diaphysis that has a double layer membrane and contains sharpey’s fibers

outer periosteum layer

layer of periosteum that is tough, connective tissue

inner periosteum layer

layer of periosteum that is adjacent to bone surface, osteogenic layer, and richly supplied with vessels that enter via a nutrient foramen

endosteum

delicate connective tissue that lines the internal marrow cavity; covers the inside of spongy bones and lines the central canal

osteon/haversian system

the structural unit of compact bone that contains haversion/central canal and osteocytes in a lacunae

haversion canal

centrally located cavity that houses blood vessels and nerves

canaliculi, concentric lamellae, intersitial lamellae, circumferential lamellae, and volkman’s canal

what are the different osteocytes in the lacunae of the osteon/haversion system?

canaliculi

small crevices that connects osteocytes

concentric lamellae

layers of matrix arranged around the central canal

interstitial lamellae

remains of old osteons between osteons

circumferential lamellae

run parallel to bone surface

volkmann’s canal

run perpindicular/diagonal to central canal

trabeculae

lattice-like network of matrix in spongy bone where osteocytes are confined to lacunae and form along lines of stress

\-covered in endosteum

\-spongy bone contains copious amounts of open space filled with bone marrow