bone physiology

function of bone/skeleton

protection, support, allow movement/lever system, storage deposit for Ca and P salts, and hematopoiesis

classes of bones

long bones, short bones, flat bones, irregular bones, sesamoid bones,

gross structure of a long bone

diaphysis, metaphysis, epiphysis, marrow cavity

diaphysis

long skinny shaft in center

metaphysis

neck where bone gets wider

epiphysis

after metaphysis and end of long bone, has spongy bone filled with red bone marrow

marrow cavity

filled with yellow bone marrow with fat

central canal

center filled with blood vessels and nerves

lamellae

ring mineralized matrix around canal

lacunae

small space between lamellae housing osteocytes

canaliculi

tiny channel connecting lacunae to each other and central canal

compact bone

A dense form of bone tissue that provides strength and support, primarily found in the outer layer of bones, contains osteons

spongy bone

a lighter, less dense bone tissue that has a lattice-like structure with trabeculae

gross structure of a long bone

periosteum and endosteum

periosteum

tough connective tissue that wraps the outside of the bone

endosteum

thin membrane that lines the inside of a bone

fibrous

dense irregular connective tissue that is the most superficial part of the periosteum

gross structure of a long bone

epiphyseal plate, epiphyseal line, articular cartilage, hyaline cartilage

epiphyseal plate

the growth plate of a long bone

epiphyseal line

the leftover line of cartilage after the epiphyseal plate closes when bone growth in length is finished

articular cartilage

layer of hyaline cartilage that covers the ends of bones at a joint

hyaline cartilage

smooth glassy looking matrix that provides support, cushioning, and reduces friction

2 types of bone formation

intramembranous and endochondral

fontanelles

large areas of dense connective tissue that provide flexibility during birth and growth

appositional growth

bone getting wider by adding new bone matrix onto the outer surface of existing bone

wolff’s law

bones remodel in response to compressive force

what does an increase of PTH stimulate?

osteoclasts

what does a decrease of calcitonin inhibit/stimulate?

inhibit: osteoclasts stimulate: osteoblasts

osteoporosis

a condition characterized by weakened bones and increased fracture risk due to bone density loss

kyphosis

due to osteoporosis, can cause curvature in spine, decrease lung capacity, decrease circulation, and compressed nerves

steps for bone repair

hematoma, soft callus, bony callus, remodeling

hematoma

immediately after fracture, blood clot forms

soft callus

cells invade hematoma

bony callus

fibrocartilage replaced by spongy bone

remodeling

spongy bone replaced by compact bone

closed fracture

contained within the skin

open fracture

breaks through the skin

greenstick fracture

small crack that doesn’t break through all the way commonly seen in children