bone lecture exam - anatomy & phys

Osteoporosis

diseases in which bone resorption exceeds deposit. Matrix remains normal, but bone mass declines. Spongy bone of spine and neck of femur most susceptible(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

Position of bone ends after fracture

Nondisplaced: ends retain the normal position
Displaced: ends are out of normal alignment

Completeness of break

Complete: broken all the way through
Incomplete: not broken all the way through

Whether skin is penetrated

Open (compound): skin is penetrated
Closed (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 and the thoracic cage

Irregular Bone

spinal column (sacrum, vertebrae) and the pelvis

Sesamoid Bone

patella

Short Bone

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

Look at a long bone and identify the parts

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)

Endochondrial ossification

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

intramembranous ossification

Bone develops from Fibrous membrane
Bones are called membrane bones
Forms frontal, parietal, occipital, temporal, and clavicle bone

interamembranous ossification steps

-Ossification centers appear in the fibrous connective tissue membrane.
-Osteoid is secreted within the fibrous membrane and calcifies.
-Woven bone and periosteum form.
-Lamellar bone replaces woven bone, just deep to the periosteum. Red marrow appears.

endochondrial ossification steps

-Bone collar forms around hyaline cartilage model.
-Cartilage in the center of the diaphysis calcifies and then develops cavities.
-The periosteal bud invades the internal cavities and spongy bone forms.
-The diaphysis elongates and a medullary cavity forms. Secondary ossification centers appear in the epiphyses.
-The epiphyses ossify. When completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages.

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

What is diploe?

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

Functions of bones

support
protection
movement
triglyceride(fat) storage
mineral storage
blood cell formation
hormone production

What is an 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

growth in length

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

collagen fibres

What is the effect on calcitonin in humans?

lower calcium levels in your blood

What makes up spongy bone?

Spongy bone consists of plates (trabeculae) and bars of bone adjacent to small, irregular cavities that contain red bone marrow.

What is osteogenesis?

the process of bone tissue formation

Comminuted fracture

bone breaks into 3 or more fragments

Spiral fracture

a fracture in which the bone has been twisted apart

greenstick fracture

(incomplete 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

What is Wolf's law?

states that your bones will adapt based on the stress or demands placed on them. When you work your muscles, they put stress on your bones. In response, your bone tissue remodels and becomes stronger