anatomy bone physiology

Osteoporosis

diseases in which bone resorption exceeds deposit. Matrix remains normal, but bone mass declines (Vertebral and hip fractures common)

Paget's disease

Excessive and haphazard bone deposit and resorption cause bone to be made fast and poorly

osteomalacia

Bones are poorly mineralized, results in soft, weak bones (Pain upon bearing weight) Rickets on children

four stages of healing in a fracture

Hematoma formation, Fibrocartilaginous callus formation, bony callus formation, bone remodeling

Nondisplaced

Position of bone ends after fracture

__: ends retain the normal position

displaced

Position of bone ends after fracture

___: ends are out of normal alignment

Complete

Completeness of break

broken all the way through

incomplete

__: not broken all the way through

compound

Whether skin is penetrated

skin is penetrated

simple

___ skin is not penetrated

epiphyseal line

remnant of the epiphyseal plate, seen in adult bones

epiphyseal plate

Growth plate, made of cartilage, gradually ossifies

Long Bone

a bone that has a shaft and 2 ends and is longer than it is wide

Flat Bone

skull, the thoracic cage, and the pelvis

Irregular Bone

spinal column (sacrum, vertebrae)

Sesamoid Bone

patella

Short Bone

tarsals (ankle bones), patella (kneecap), and carpals (wrist bones)

Endochondrial ossification

Bone forms by replacing Hyaline Cartilage. Forms essentially all bones inferior to base of skull, except clavicles

endochondral ossification

Closed Reduction

physician manipulates to correct position

Open reduction

surgical pins or wires secure ends

Hyaline cartilage

Provides support, flexibility, and resilience

Most abundant type; contains collagen fibers only

EX: Articular (joints), costal (ribs), respiratory (larynx), nasal cartilage (nose tip)

Elastic cartilage

Similar to hyaline cartilage, but contains elastic fibers

EX: External ear and epiglottis

Fibrocartilage

Thick collagen fibers: has great tensile strength

EX: Menisci of knee; vertebral discs

Red Marrow

found within trabecular cavities of spongy bone and diploë of flat bones, such as the sternum

Yellow bone marrow

made mostly of fat and contains stem cells that can become cartilage, fat, or bone cells

Found in long bones

Yellow marrow can convert to red if...

person becomes anemic

Osteoblasts

Bone-forming cells that secrete unmineralized bone matrix called osteoid

Osteogenic cells

Mitotically active stem cells in periosteum and endosteum

Osteocytes

Maintain bone matrix

Bone lining cells

Flat cells on bone surfaces believed to also help maintain matrix (along with osteocytes)

Osteoclasts

bone resorption (breakdown of bone)

Endochondral

Bone forms by replacing Hyaline Cartilage

Bones are called cartilage () bones

Intramembranous

Bone develops from Fibrous membrane

Bones are called membrane bones

Endochondral forms

all bones except skull and clavicle

Intramembranous forms

frontal, parietal, occipital, temporal, and clavicle bone

interamembranous ossification

Growth hormone

most important hormone in stimulating epiphyseal plate activity in infancy and childhood

Thyroid hormone

modulates activity of growth hormone, ensuring proper proportions

testosterone

(males) at puberty promote adolescent growth spurts

estrogen

(females) at puberty promote adolescent growth spurts

diploe

the spongy layer between the inner and outer compact layers of the flat bones of the skull.

Functions of bones

support

protection

movement \n triglyceride(fat) storage \n mineral storage \n blood cell formation \n hormone production

osteon

(Haversian system) structural unit of compact bone;Acts as tiny weight-bearing pillars

Sharpey's fibres

(bone fibres, or perforating fibres)

\
are a matrix of connective tissue consisting of bundles of strong collagenous fibres connecting periosteum to bone

Fibrous layer

outer layer consisting of dense irregular connective tissue consisting of Sharpey's that secure to bone matrix

Periosteum

Fibrous layer, Osteogenic layer

Perforating (Volkmann's) canals

canals lined with endosteum that occur at right angles to the central canal

Central (Haversian) canal

runs through core of osteon, contains blood vessels and nerve fibers

appositional growth

growth in width

Interstitial

growth in length

collagen

What is responsible for the hardness and allows bone to resist compression?

lower calcium levels

What is the effect on calcitonin in humans?

trabeculae

What makes up spongy bone?

bone tissue formation

What is osteogenesis?

Comminuted fracture

bone breaks into 3 or more fragments

Spiral fracture

a fracture in which the bone has been twisted apart

greenstick fracture

bending and incomplete break of a bone; most often seen in children

Compound fracture

bone breaks through the skin

Displaced fracture

bone ends are out of normal alignment

Depressed fracture

broken bone portion is pressed inward

Simple fracture

bone is broken cleanly; the ends do not penetrate the skin

Compression fracture

bone is crushed

Wolf's law

states that bones grow or remodel in response to demands placed on them